Electrode assembly, battery cell, battery and electric device

Abstract

The utility model provides an electrode assembly, a battery monomer, a battery and a power utilization device. The electrode assembly comprises a main body part and at least one tab, the tab comprises a plurality of sub-tabs which extend out from one end of the main body part and are arranged in a laminated manner, the plurality of sub-tabs are welded and connected to form a welding part, the welding part comprises a thinned area, and the thickness of the thinned area is smaller than the maximum thickness of the welding part. And the production efficiency and the yield of the battery can be improved.

Description

[0001] Related Documents

[0002] This application claims priority to Chinese Patent Application No. 202210612416.3, filed on May 31, 2022, entitled “Electrode Assembly, Battery Cell, Battery and Electric Device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of batteries, in particular to an electrode assembly, a battery cell, a battery and an electric device. BACKGROUND

[0004] Batteries have been widely used in consumer electronic devices, power devices and other devices due to their high energy density, good cycle performance and rechargeability.

[0005] The reliable connection between the components included in the battery during the production process directly affects the production efficiency and yield of the battery. Therefore, it is urgent to improve the reliable connection between the components in the battery. UTILITY MODEL CONTENT

[0006] The present application provides an electrode assembly, a battery cell, a battery and an electric device, which can improve the production efficiency and yield of the battery.

[0007] In a first aspect, the present application provides an electrode assembly, comprising a main body and at least one tab. The tab comprises a plurality of sub-tabs extending from one end of the main body and stacked, the plurality of sub-tabs being welded and forming a welded portion, the welded portion comprising a thinned region, the thickness of the thinned region being less than the maximum thickness of the welded portion.

[0008] In the above embodiment, the plurality of sub-tabs included in the tab are welded to form a welded portion, which can improve the connection reliability between the plurality of sub-tabs, further ensuring the overcurrent capacity of the electrical connection between the electrode terminal and the electrode tab. In addition, the welded portion comprises a thinned region, the thickness of which is less than the maximum thickness of the welded portion, which can help to improve the electrical connection reliability between the plurality of sub-tabs in the tab and the electrode terminal, thereby improving the production efficiency and yield of the battery.

[0009] In some embodiments of the present application, the thinned region is configured to be recessed relative to at least one surface of the welded portion and form at least one recess.

[0010] In the above embodiment, the recess can help to electrically connect the plurality of sub-tabs and the electrode terminal.

[0011] In some embodiments of the present application, the ratio of the depth of the recess to the maximum thickness of the welding portion in the thickness direction of the welding portion is in the range of 0.3-0.7.

[0012] In the above embodiments, the ratio of the depth of the recess to the maximum thickness of the welding portion is set to facilitate the electrical connection between the tab and the electrode terminal.

[0013] In some embodiments of the present application, the thickness of the bottom wall of the recess in the thickness direction of the welding portion is less than or equal to 2mm.

[0014] In the above embodiments, the thickness of the bottom wall of the recess is set to further improve the reliability of the electrical connection between the tab and the electrode terminal.

[0015] In some embodiments of the present application, the recess is a profiled recess, and the shape of the profiled recess is adapted to the path for electrically connecting the thinned area and the electrode terminal of the battery cell.

[0016] In the above embodiments, the provision of the profiled recess can reduce the area of the thinned area, so as to reduce the heat generated when the tab overflows.

[0017] In some embodiments of the present application, the shape of the profiled recess is strip-shaped.

[0018] In the above embodiments, on the one hand, the strip-shaped profiled recess can facilitate the electrical connection between the profiled recess and the electrode terminal. On the other hand, the strip-shaped profiled recess can make the thinned area have a smaller area, so as to improve the overcurrent capacity of the non-thinned area, and further reduce the heat generated when the tab overflows. In addition, the strip-shaped profiled recess has a smaller processing difficulty, and is convenient to manufacture.

[0019] In some embodiments of the present application, the shape of the profiled recess is ring-shaped.

[0020] In the above embodiments, on the one hand, the ring-shaped profiled recess can facilitate the electrical connection between the profiled recess and the electrode terminal. On the other hand, the ring-shaped profiled recess can enhance the electrical connection reliability of the thinned area and the electrode terminal of the battery cell.

[0021] In some embodiments of the present application, the number of profiled recesses is multiple.

[0022] In the above embodiments, the number of profiled recesses is set to multiple, which can further enhance the electrical connection reliability of the thinned area and the electrode terminal of the battery cell.

[0023] In some embodiments of the present application, the surface of the welding portion includes a first surface and a second surface oppositely arranged in the thickness direction of the welding portion, the recess is formed on the first surface, and the second surface is used to electrically connect the electrode terminal.

[0024] In the above embodiment, the recess is formed on the first surface of the welding portion, and the second surface is used for electrically connecting the electrode terminal, so that the tab can be closely attached to the electrode terminal, thereby reducing the possibility of false welding and making the electrical connection between the tab and the electrode terminal more reliable.

[0025] In some embodiments of the present application, the recess is formed by stamping or swaging.

[0026] In the above embodiment, the recess is formed by stamping or swaging, which can reduce the generation of metal particles during the formation of the recess, thereby reducing the occurrence of internal short circuit of the battery.

[0027] In some embodiments of the present application, in the extension direction of the tab, the ratio of the size of the welding portion to the total size of the tab is in the range of 0.2-0.8.

[0028] In the above embodiment, the ratio of the size of the welding portion to the total size of the tab is set, which can help to weld multiple sub-tabs to form the welding portion, and also help to form a thinning area on the welding portion to improve the reliability of the electrical connection between the tab and the electrode terminal.

[0029] In some embodiments of the present application, in the extension direction of the tab, the size of the welding portion is 5mm-10mm.

[0030] In the above embodiment, the size of the welding portion is set, which can improve the reliability of welding between multiple tabs to form a stable welding portion. And it is also convenient to form a thinning area on the welding portion.

[0031] In some embodiments of the present application, the multiple sub-tabs are ultrasonically welded to form the welding portion.

[0032] In the above embodiment, ultrasonic welding of multiple sub-tabs can quickly form a welding portion, and the connection between multiple sub-tabs in the welding portion is very firm.

[0033] In some embodiments of the present application, the tab includes a connecting portion connected between the main body portion and the welding portion, and in the connecting portion, the multiple sub-tabs are separately arranged.

[0034] In the above embodiment, the setting of the connecting portion can help to bend the tab and accommodate it in the shell of the battery.

[0035] In some embodiments of the present application, the electrode assembly further includes an insulating member, the welding portion further includes a non-thinning area, and the insulating member is arranged on at least one surface of the connecting portion and the non-thinning area.

[0036] In the above embodiment, the insulation member is arranged to reduce the electrical connection between the tab and other components, thereby reducing the occurrence of internal short circuit of the battery.

[0037] In some embodiments of the present application, the tab includes a first tab and a second tab. The thinned region of the first tab is configured to electrically connect a first electrode terminal of the battery cell. The second tab is opposite in polarity to the first tab, and the thinned region of the second tab is configured to electrically connect a second electrode terminal of the battery cell, the second electrode terminal being opposite in polarity to the first electrode terminal.

[0038] In the above embodiment, the tab can include a first tab and a second tab, and the thinned regions of the first and second tabs are configured to electrically connect a first electrode terminal and a second electrode terminal of the battery cell, respectively, so as to reduce the thickness of the tab and make the electrical connection between the tab and the electrode terminal more reliable.

[0039] In a second aspect, the present application provides a battery cell including a housing, an electrode terminal, and the electrode assembly of any one of the above embodiments. The electrode terminal is arranged in the housing. The electrode assembly is accommodated in the housing, and the thinned region is electrically connected to the electrode terminal.

[0040] In the above embodiment, the battery cell includes the electrode assembly of the above embodiment, and thus the battery cell has high production efficiency and yield during production. In addition, the main body portion of the electrode assembly is composed of multiple positive and negative electrode sheets, and the electrical connection between the tab and the electrode terminal is reliable, so that the battery cell has high power density.

[0041] In some embodiments of the present application, the thinned region and the electrode terminal are connected by laser welding and form a weld mark.

[0042] In the above embodiment, the thinned region can thin the tab, so as to reduce the risk of false welding of the thinned region and the electrode terminal by laser welding.

[0043] In a third aspect, the present application provides a battery including the battery cell of any one of the above embodiments.

[0044] In a fourth aspect, the present application further provides an electric device including the battery of the above embodiment, the battery being used to provide electric energy.

[0045] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application, the following detailed description of the embodiments of the present application can be implemented according to the content of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand. BRIEF DESCRIPTION OF DRAWINGS

[0046] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments with reference made to the accompanying drawings. The drawings are for purposes of illustration only and are not intended to limit the scope of the present application. The same reference numbers in different drawings identify the same components or elements. In the drawings:

[0047] Figure 1 A structural schematic diagram of a vehicle provided by some embodiments of the present application is shown;

[0048] Figure 2 An exploded view of a battery provided by some embodiments of the present application is shown;

[0049] Figure 3 An exploded view of a battery cell provided by some embodiments of the present application is shown;

[0050] Figure 4 An exploded view of a battery cell provided by some embodiments of the present application is shown;

[0051] Figure 5 A partial enlarged view of a battery cell provided by some embodiments of the present application is shown;

[0052] Figure 6 A structural schematic diagram of an electrode assembly provided by some embodiments of the present application is shown;

[0053] Figure 7 A structural schematic diagram of an electrode assembly provided by some embodiments of the present application is shown;

[0054] Figure 8 A structural schematic diagram of an electrode assembly provided by some embodiments of the present application is shown;

[0055] Figure 9 A structural schematic diagram of an electrode assembly provided by some embodiments of the present application is shown.

[0056] Reference signs in the detailed description of the embodiments are as follows:

[0057] A vehicle 1000;

[0058] A battery 100, a controller 200, a motor 300;

[0059] A case 10, a first portion 11, a second portion 12;

[0060] A battery cell 20;

[0061] A housing 21, an end cap 211, a shell 212, an insulating shell 213;

[0062] An electrode terminal 22, a first electrode terminal 1, a second electrode terminal 2;

[0063] Electrode assembly 23;

[0064] Body portion 231;

[0065] Tab 232, welding portion 2321, thinning region 2321A, recess 2321a, non-thinning region 2321B, connecting portion 2322. DETAILED DESCRIPTION

[0066] The embodiments of the present application will be described in detail with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical scheme of the present application, and therefore only serve as examples, but cannot be used to limit the protection scope of the present application.

[0067] 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 herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the present specification and claims and the aforementioned description of the drawings are not intended to be all inclusive in terms of encompassing the full scope of the present application; the terms "comprising," "having," "including," and "containing" as used herein are meant to be interpreted in a non- limiting manner.

[0068] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly and specifically limited.

[0069] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0070] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents a "or" relationship between the front and rear associated objects.

[0071] In the description of the embodiments of the present application, the term "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0072] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0073] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0074] The battery has been widely used in consumer electronic devices, power devices and other devices due to its high energy density, good cycle performance, and rechargeable performance.

[0075] In the present application, the battery refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application can include a battery module or a battery pack, etc. The battery usually also includes a box for packaging one or more battery cells, which can avoid the influence of liquid or other foreign matters on the charging or discharging of the battery cells.

[0076] In the present application, the battery cell can include a lithium ion secondary battery cell, a lithium ion primary battery cell, a lithium-sulfur battery cell, a sodium lithium ion battery cell, a sodium ion battery cell or a magnesium ion battery cell, etc., and the embodiments of the present application are not limited thereto. The battery cell can be in the shape of a cylinder, a flat body, a cuboid or other shapes, and the embodiments of the present application are not limited thereto.

[0077] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer coated on the surface of the positive electrode current collector; the positive electrode current collector includes a positive electrode current collecting portion and a positive electrode tab connected to the positive electrode current collecting portion, the positive electrode current collecting portion is coated with the positive electrode active material layer, and the positive electrode tab is not coated with the positive electrode active material layer. Taking a lithium ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material layer includes a positive electrode active material, which can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer coated on the surface of the negative electrode current collector; the negative electrode current collector includes a negative electrode current collecting portion and a negative electrode tab connected to the negative electrode current collecting portion, the negative electrode current collecting portion is coated with the negative electrode active material layer, and the negative electrode tab is not coated with the negative electrode active material layer. The material of the negative electrode current collector can be copper, and the negative electrode active material layer includes a negative electrode active material, which can be carbon or silicon, etc. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc.

[0078] The battery cell further includes a shell for accommodating the electrode assembly and an electrode terminal arranged on the shell, wherein the portions of the positive electrode sheet and the negative electrode sheet having the active material constitute a main body portion of the electrode assembly, and the portions of the positive electrode sheet and the negative electrode sheet not having the active material each constitute a tab. In order to improve the overcurrent capacity, the tab includes a plurality of layers of sub-tabs arranged in a stack, and in the charging and discharging process of the battery cell, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab connects the electrode terminal to form a current loop.

[0079] With the development of battery technology, higher and higher requirements are put forward for the energy density of the battery. The increase of the energy density of the battery can be realized by increasing the number of layers or the thickness of the positive and negative electrode sheets in the electrode assembly. At this time, the number of layers and the thickness of the tabs in the electrode assembly will also increase with the number of layers or the thickness of the positive and negative electrode sheets.

[0080] In the production process of the battery, the tab is generally electrically connected to the electrode terminal by welding.

[0081] However, the inventors have found that when the thickness of the tab reaches a certain thickness, the requirements for the power of the welding and the welding process are higher, the possibility of welding defects such as false welding increases, the connection reliability between the multi-layer tabs decreases, and the connection reliability between the tab and the electrode terminal decreases, thereby affecting the electrical connection between the electrode assembly and the electrode terminal, and leading to the decrease of the production efficiency and the yield of the battery.

[0082] In view of this, the electrode assembly, the battery monomer, the battery and the electric device provided by the embodiments of the present application can improve the connection reliability between the plurality of sub-tab included in the tab and the electrode terminal, and further ensure the overcurrent capacity of the electrical connection between the electrode terminal and the tab. In addition, the welding portion includes a thinning area, and the thickness of the thinning area is less than the maximum thickness of the welding portion, which can help to improve the electrical connection reliability between the plurality of sub-tab in the tab and the electrode terminal, thereby improving the production efficiency and yield of the battery.

[0083] The electrode assembly described in the embodiments of the present application is suitable for battery monomers, batteries and electric devices using batteries.

[0084] The electric device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, etc. Among them, the electric toy can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric plane toys, etc., and the spacecraft can include airplanes, rockets, space shuttles and spaceships, etc.

[0085] The following embodiments are described for the convenience of illustration, taking a vehicle 1000 as an example for the electric device of an embodiment of the present application.

[0086] Figure 1 The structural schematic diagram of the vehicle provided by some embodiments of the present application is shown.

[0087] Please refer to Figure 1 The vehicle 1000 can be a fuel car, a gas car or a new energy car, and the new energy car can be a pure electric car, a hybrid car or an extended range car, etc. The vehicle 1000 is internally provided with a battery 100, which can be arranged at the bottom, head or tail of the vehicle 1000. The battery 100 can be used for power supply of the vehicle 1000, for example, the battery 100 can be used as the operating power supply of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the working power demand of the vehicle 1000 during starting, navigation and driving.

[0088] In some embodiments of the present application, the battery 100 can not only be used as the operating power supply of the vehicle 1000, but also be used as the driving power supply of the vehicle 1000, instead of or partially instead of fuel or natural gas to provide driving power for the vehicle 1000.

[0089] Figure 2 The exploded view of the battery provided by some embodiments of the present application is shown.

[0090] Please refer to Figure 2The battery 100 includes a case 10 and a battery cell 20 housed in the case 10.

[0091] The case 10 is configured to provide a housing space for the battery cell 20. The case 10 can have various configurations. In some embodiments, the case 10 can include a first portion 11 and a second portion 12. The first portion 11 and the second portion 12 are coupled to each other to define a housing space for the battery cell 20. The second portion 12 can be a hollow structure with one open end, and the first portion 11 can be a plate-shaped structure. The first portion 11 is coupled to the open end of the second portion 12 to define the housing space together with the second portion 12. Alternatively, the first portion 11 and the second portion 12 can each be a hollow structure with one open end. The open end of the first portion 11 is coupled to the open end of the second portion 12. The case 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylindrical shape, a cuboid shape, etc.

[0092] In the battery 100, the battery cell 20 can be a plurality of battery cells 20. The plurality of battery cells 20 can be connected in series, in parallel, or in a mixed connection. The mixed connection means that the plurality of battery cells 20 are connected in series and in parallel. The plurality of battery cells 20 can be directly connected in series, in parallel, or in a mixed connection. The plurality of battery cells 20 are housed in the case 10. Alternatively, the plurality of battery cells 20 can be connected in series, in parallel, or in a mixed connection to form a battery module. A plurality of battery modules are connected in series, in parallel, or in a mixed connection to form a whole, which is housed in the case 10.

[0093] Each of the battery cells 20 can be a secondary battery cell or a primary battery cell. The battery cell 20 can be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited thereto. The battery cell 20 can have a cylindrical shape, a flat shape, a cuboid shape, or other shapes.

[0094] Figure 3 An exploded view of a battery cell according to some embodiments of the present application is shown. Figure 4 An exploded view of a battery cell according to some other embodiments of the present application is shown, in which a housing is omitted. Figure 5 A partial enlarged view of a battery cell according to some embodiments of the present application is shown.

[0095] Referring to Figure 3 and Figure 4 The battery cell 20 refers to the smallest unit constituting a battery, and includes a housing 21, an electrode assembly 23 housed in the housing 21, and other functional components.

[0096] Referring to Figure 3-5The shell 21 includes an end cover 211 and a casing 212. The end cover 211 can be coupled to the casing 212 to seal the internal environment of the battery cell 20 from the external environment. The end cover 211 can be shaped to fit the casing 212. The end cover 211 can be made of a material with certain hardness and strength, such as aluminum alloy, so that the end cover 211 is less likely to deform when subjected to a pressing impact, and the battery cell 20 can have higher structural strength and safety performance. In addition, the end cover 211 can be provided with functional components such as the electrode terminal 22. The electrode terminal 22 can be electrically connected to the electrode assembly 23 for outputting or inputting the power of the battery cell 20.

[0097] The material of the end cover 211 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not specifically limited in the embodiments of the present application.

[0098] In some embodiments of the present application, an insulating member can be further provided on the inner side of the end cover 211. The insulating member can be used to isolate the electrical connection part 2322 in the casing 212 from the end cover 211 to reduce the risk of short circuit. The insulating member can be plastic, rubber, etc.

[0099] The casing 212 is a component for fitting the end cover 211 to form the internal environment of the battery cell 20, which can be used to accommodate the electrode assembly 23, electrolyte and other components. The casing 212 and the end cover 211 can be independent components, and the casing 212 can be provided with an opening. The end cover 211 can be coupled to the casing 212 to form the internal environment of the battery cell 20. The end cover 211 and the casing 212 can be integrated, specifically, the end cover 211 and the casing 212 can form a common connecting surface before other components enter the casing. When it is necessary to seal the internal environment of the casing 212, the end cover 211 can be coupled to the casing 212. The casing 212 can have various shapes and sizes, such as a cuboid, a cylinder, a hexagonal prism, etc. Specifically, the shape of the casing 212 can be determined according to the specific shape and size of the electrode assembly 23. The material of the casing 212 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not specifically limited in the embodiments of the present application.

[0100] Please refer to Figure 4 and Figure 5 In some embodiments of the present application, the casing 212 is provided with an insulating shell 213. The insulating shell 213 can be used to isolate adjacent casings 212 to reduce the risk of short circuit. The insulating shell 213 can be plastic, rubber, etc.

[0101] The electrode assembly 23 is a component in which electrochemical reactions occur in the battery cell 20. One or more electrode assemblies 23 can be contained within the case 212. The electrode assembly 23 is mainly formed by winding or layering a positive electrode sheet and a negative electrode sheet, and a separator is generally provided between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet and the negative electrode sheet have portions with active materials that constitute a main body portion 231 of the electrode assembly 23, and portions without active materials that constitute a tab 232. During charging and discharging of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab 232 connects the electrode terminal 22 to form a current loop.

[0102] Figure 6 A structural diagram of an electrode assembly according to some embodiments of the present application is shown. Figure 7 A structural diagram of an electrode assembly according to some embodiments of the present application is shown. Figure 8 A structural diagram of an electrode assembly according to some embodiments of the present application is shown. Figure 9 A structural diagram of an electrode assembly according to some embodiments of the present application is shown.

[0103] Please refer to Figure 6 The electrode assembly 23 according to the embodiments of the present application includes a main body portion 231 and at least one tab 232. The tab 232 includes a plurality of sub-tabs that extend from one end of the main body portion 231 and are layered, the plurality of sub-tabs are welded together and form a welded portion 2321, and the welded portion 2321 includes a thinned region 2321A that is smaller than the maximum thickness of the welded portion 2321.

[0104] As described above, the main body portion 231 can be formed by winding or layering portions of the positive electrode sheet and the negative electrode sheet that have active materials, and a separator is provided between the positive electrode sheet and the negative electrode sheet, which can isolate the positive and negative electrode sheets and allow ions in the electrolyte to pass freely between the positive and negative electrode sheets.

[0105] In the embodiments of the present application, portions of the positive and negative electrode sheets that do not have active materials extend from one end of the main body portion 231 and form a plurality of layered sub-tabs, and the plurality of layered sub-tabs are welded to form a welded portion 2321, which can form an integral structure of the plurality of layered sub-tabs, thereby not only improving the connection reliability between the plurality of sub-tabs and ensuring the current-carrying capacity of the electrode terminal and the electrode sheet, but also facilitating improvement of the connection reliability between the tab 232 and the electrode terminal 22.

[0106] The welding portion 2321 includes a thinned region 2321A, i.e., the tab 232 thickness of the thinned region 2321A is less than the tab 232 thickness of other regions, i.e., the thinned region 2321A is less than the maximum thickness of the welding portion 2321. Therefore, in embodiments of the present application, the thinned region 2321A is configured to electrically connect the electrode terminal 22 of the battery cell 20, and the reliability of the electrical connection between the thinned region 2321A and the electrode terminal 22 is improved due to the reduced thickness of the thinned region 2321A.

[0107] In the above embodiments, the plurality of sub-tabs included in the tab 232 are welded to form the welding portion 2321, which can improve the connection reliability between the plurality of sub-tabs. Moreover, the thinned region 2321A included in the welding portion 2321 can reduce the thickness of part of the welding portion 2321, which can help to improve the electrical connection reliability between the plurality of sub-tabs in the tab 232 and the electrode terminal 22, thereby improving the production efficiency and yield of the battery.

[0108] Please refer to Figure 7 and Figure 8 In some embodiments of the present application, the thinned region 2321A is configured to be recessed relative to at least one surface of the welding portion 2321 and form at least one recess 2321a.

[0109] In the above embodiments, the provision of the recess 2321a reduces the thickness between the tab 232 and the electrode terminal 22, which reduces the difficulty of electrical connection between the tab 232 and the electrode terminal 22, thereby facilitating the electrical connection between the tab 232 and the electrode terminal 22. Moreover, the recess 2321a can reduce the height of the electrical connection portion 2322 of the tab 232 and the electrode terminal 22, thereby facilitating the subsequent bending of the tab 232 and the accommodation of the tab 232 in the housing 212 of the battery cell 20.

[0110] In some specific embodiments of the present application, the thinned region 2321A can be configured to be recessed relative to one surface of the welding portion 2321 and form one or more recesses 2321a.

[0111] In some specific embodiments of the present application, the thinned region 2321A can be configured to be recessed relative to one surface of the welding portion 2321 and form one or more recesses 2321a.

[0112] In some embodiments of the present application, the ratio of the depth of the recess 2321a to the maximum thickness of the welding portion 2321 in the thickness direction of the welding portion 2321 is in the range of 0.3-0.7.

[0113] In the above embodiments, the depth of the recess 2321a can be understood as the total thickness difference between the non-thinned region 2321B and the thinned region 2321A of the welding portion 2321, and the ratio of the depth of the recess 2321a to the maximum thickness of the welding portion 2321 is set not only to facilitate the electrical connection between the tab 232 and the electrode terminal 22, but also to enable the recess 2321a to have a relatively high strength after being electrically connected to the electrode terminal 22.

[0114] For example, the ratio of the depth of the recess 2321a to the maximum thickness of the welding portion 2321 can be, but is not limited to, 0.3, 0.4, 0.5, 0.6, or 0.7.

[0115] Further, if the maximum thickness of the welding portion 2321 is 6 mm, the depth of the recess 2321a can be any value in the range of 4 mm to 4.2 mm, such as 4 mm, 4.01 mm, etc. If the maximum thickness of the welding portion 2321 is 5 mm, the depth of the recess 2321a can be any value in the range of 3 mm to 3.5 mm, such as 3 mm, 3.01 mm, 3.02 mm, etc.

[0116] In some embodiments of the present application, the thickness of the bottom wall of the recess 2321a in the thickness direction of the welding portion 2321 is less than or equal to 2 mm.

[0117] In the above embodiments, the thickness of the bottom wall of the recess 2321a can be understood as the thickness of the thinned region 2321A, and the thickness of the thinned region 2321A is set in the above range to further improve the reliability of the electrical connection between the tab 232 and the electrode terminal 22.

[0118] For example, the thickness of the bottom wall of the recess 2321a can be, but is not limited to, 2 mm, 1.8 mm, or 1.5 mm.

[0119] In some embodiments of the present application, the recess 2321a is a profiled recess, and the shape of the profiled recess is adapted to the path for electrically connecting the thinned region 2321A and the electrode terminal 22.

[0120] For example, the thinned region 2321A and the electrode terminal 22 can be electrically connected by welding, and thus the path of the welding can be understood as the electrical connection path of the thinned region 2321A and the electrode terminal 22.

[0121] In the above embodiments, the profiled recess is formed according to the shape of the electrical connection portion 2322 of the electrode terminal 22, and the profiled recess is adapted to the shape of the electrical connection portion 2322, which can reduce the area of the thinned region 2321A and enable the non-thinned region 2321B to have a better overcurrent capacity, thereby effectively reducing the heat generated by the tab 232 when passing current.

[0122] Please refer toFigure 7 and Figure 8 In some embodiments of the present application, the shape of the profiling recess is strip-shaped.

[0123] In the above embodiments, on the one hand, the strip shape facilitates the electrical connection between the profiling recess and the electrode terminal 22. On the other hand, the strip shape can make the thinned region 2321A have a smaller area, so that the overcurrent capacity of the non-thinned region 2321B is improved, and the heat generated by the tab 232 during overcurrent is further reduced. In addition, the strip shape is less difficult to process, facilitating manufacturing.

[0124] In some embodiments of the present application, the shape of the profiling recess is ring-shaped.

[0125] In the above embodiments, on the one hand, the ring shape facilitates the electrical connection between the profiling recess and the electrode terminal 22. On the other hand, the ring shape can enhance the electrical connection reliability of the thinned region 2321A and the electrode terminal 22.

[0126] In some embodiments of the present application, the number of profiling recesses is multiple.

[0127] In the above embodiments, the number of profiling recesses is set to multiple, which can further enhance the electrical connection reliability of the thinned region 2321A and the electrode terminal 22.

[0128] In some other embodiments of the present application, the shape of the profiling recess can also be other shapes, such as square, circular, etc.

[0129] In some embodiments of the present application, the surface of the welding portion 2321 includes a first surface and a second surface oppositely arranged along the thickness direction of the welding portion 2321, the recess 2321a is formed on the first surface, and the second surface is used for electrically connecting the electrode terminal 22.

[0130] In the above embodiments, the recess 2321a is formed on the first surface of the welding portion 2321, and the second surface of the welding portion 2321 is used for electrically connecting the electrode terminal 22, so that the tab 232 and the electrode terminal 22 are tightly fitted to reduce the possibility of false welding and make the electrical connection between the tab 232 and the electrode terminal 22 more reliable.

[0131] In some other embodiments of the present application, the recess 2321a can be formed on the second surface of the welding portion 2321, which can be used for electrically connecting the electrode terminal 22. Specifically, the recess 2321a can be filled with conductive glue, and the electrode terminal 22 is connected through the conductive glue.

[0132] In some embodiments of the present application, the recess 2321a is formed by stamping or upsetting.

[0133] In the above embodiments, the recess 2321a is formed by punching or swaging, which can reduce metal particles generated during the formation of the recess 2321a, thereby reducing the occurrence of internal short circuit of the battery.

[0134] In some embodiments of the present application, the recess 2321a can also be formed by other processes, such as cutting, grinding, etc.

[0135] In some embodiments of the present application, in the extension direction of the tab 232, the ratio of the size of the welding portion 2321 to the total size of the tab 232 is in the range of 0.2-0.8.

[0136] In the above embodiments, in the extension direction of the tab 232, the total size of the tab 232 is the total size of the tab 232 extending from the main body portion 231, and the ratio of the size of the welding portion 2321 to the total size of the tab 232 is set, which can help the plurality of sub-tabs to be welded to form the welding portion 2321, and also can help the formation of the thinning area 2321A on the welding portion 2321 to improve the reliability of the electrical connection between the tab 232 and the electrode terminal 22.

[0137] For example, the ratio of the size of the welding portion 2321 to the total size of the tab 232 can be but is not limited to 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8.

[0138] In some embodiments of the present application, the total size of the tab 232 is 20-25 mm, and the total size set in the above range can facilitate the accommodation of the tab 232 in the housing 212 of the battery cell 20.

[0139] Based on the above embodiments, the size of the welding portion 2321 can be any value in the range of 5-16 mm, such as 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm.

[0140] In some embodiments of the present application, in the extension direction of the tab 232, the size of the welding portion 2321 is 5-10 mm.

[0141] In the above embodiments, the size of the welding portion 2321 is set, which can improve the reliability of the welding between the plurality of tabs 232 to form a stable welding portion 2321. Also, it can facilitate the formation of the thinning area 2321A on the welding portion 2321.

[0142] For example, the size of the welding portion 2321 can be but is not limited to 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm.

[0143] In some embodiments of the application, the plurality of sub-tab is ultrasonically welded to form the welded portion 2321.

[0144] In the above embodiments, the plurality of sub-tab is ultrasonically welded to form the welded portion 2321 quickly, and the plurality of sub-tab in the welded portion 2321 is ultrasonically welded to make the connection between the sub-tab more firm.

[0145] In some other embodiments of the application, the plurality of sub-tab can also be welded to form the welded portion 2321 by other ways, such as laser welding, resistance welding, etc.

[0146] Please refer to Figure 9 In some embodiments of the application, the tab 232 comprises a connecting portion 2322, which is connected between the main portion 231 and the welded portion 2321, and in the connecting portion 2322, the plurality of sub-tab is detachably arranged.

[0147] In the above embodiments, the connecting portion 2322 can help the tab 232 to be bent and accommodated in the battery.

[0148] In some embodiments of the application, the thinned region 2321A extends from the welded portion 2321, so that part of the thinned region 2321A is arranged overlapping the welded portion 2321. For example, the thinned region 2321A can extend from the welded portion 2321 to the connecting portion 2322, which can help the tab 232 to be bent and accommodated in the housing 212 of the battery monomer 20.

[0149] Please refer to Figure 9 In some embodiments of the application, the electrode assembly 23 further comprises an insulating member (not shown in the figure), and the welded portion 2321 further comprises a non-thinned region 2321B, and the insulating member is arranged on at least one surface of the connecting portion 2322 and the non-thinned region 2321B.

[0150] In the above embodiments, the arrangement of the insulating member can be used to isolate the tab 232 from other electrical connection members 2322 to reduce the risk of short circuit.

[0151] For example, the insulating member can be plastic, rubber, etc., such as insulating blue glue.

[0152] In some embodiments of the application, the insulating member can be arranged on two opposite surfaces of the connecting portion 2322 and the non-thinned region 2321B, or can be arranged on one surface of the connecting portion 2322 and the non-thinned region 2321B.

[0153] In some embodiments of the present application, the insulating member is arranged on one surface of the connecting portion 2322 and the non-thinned region 2321B, wherein the surface of the connecting portion 2322 on which the insulating member is arranged is the surface of the tab 232 facing the main body portion 231 after the tab 232 is accommodated in the housing 212 of the battery cell 20, and the surface of the non-thinned region 2321B on which the insulating member is arranged is the surface away from the surface on which the thinned region 2321A is arranged.

[0154] In some embodiments of the present application, the tab 232 includes a first tab and a second tab. The thinned region 2321A of the first tab is configured to electrically connect a first electrode terminal of the battery cell 20. The second tab is opposite in polarity to the first tab, and the thinned region 2321A of the second tab is configured to electrically connect a second electrode terminal of the battery cell 20, the second electrode terminal being opposite in polarity to the first electrode terminal.

[0155] In the above embodiments, the tab 232 can include a first tab and a second tab, and the thinned regions 2321A of the first tab and the second tab are respectively configured to electrically connect a first electrode terminal and a second electrode terminal of the battery cell 20, so as to reduce the thickness of the tab 232 and make the electrical connection between the tab 232 and the electrode terminal 22 more reliable.

[0156] For example, the first tab can be a negative tab, the first electrode terminal can be a positive electrode terminal, the second tab can be a positive tab, and the second electrode terminal can be a negative electrode terminal.

[0157] In some embodiments of the present application, the first tab and the second tab can extend from the same side of the main body portion 231, or can extend from opposite sides respectively.

[0158] In some embodiments of the present application, the first tab and the second tab extend from opposite sides of the main body portion 231 respectively, so as to help the working temperature of the battery to be uniformly distributed.

[0159] Further, the first tab and the second tab extend from opposite diagonal positions of the main body portion 231 respectively, so as to not only help the working temperature of the battery to be uniformly distributed, but also help to reduce the working temperature of the battery.

[0160] For more details, please refer to Figure 4-5 According to some embodiments of the present application, the present application further provides a battery cell 20 including a housing 21, an electrode terminal 22, and an electrode assembly 23 according to any one of the above embodiments. The electrode terminal 22 is arranged on the housing 21. The electrode assembly 23 is accommodated in the housing 21, and the thinned region 2321A is electrically connected to the electrode terminal 22.

[0161] In the above embodiments, the battery cell 20 includes the electrode assembly 23 in the above embodiments, and thus the battery cell 20 has high production efficiency and yield in the production process. In addition, the main body part 231 in the electrode assembly 23 is composed of the plurality of positive and negative electrode sheets, and the electrical connection reliability between the tab 232 and the electrode terminal 22 is improved, and thus the battery cell 20 has high capacity density.

[0162] In some embodiments of the present application, the thinning area 2321A and the electrode terminal 22 are connected by laser welding and form a welding spot.

[0163] In the above embodiments, since the thinning area 2321A can thin the tab 232, it can reduce the risk of virtual welding of laser welding between the thinning area 2321A and the electrode terminal 22. In addition, the position of the welding spot can reduce the generation of metal particles between the tab 232 and the electrode terminal 22, thereby reducing the occurrence of internal short circuit of the battery.

[0164] According to some embodiments of the present application, the present application also provides a battery including the battery cell in any of the above embodiments.

[0165] In the above embodiments, since the battery includes the battery cell in any of the above embodiments, the battery has high capacity density.

[0166] According to some embodiments of the present application, the present application also provides a power utilization device including the battery in the above embodiments, and the battery is used to provide electric energy.

[0167] According to some embodiments of the present application, the electrode assembly 23 includes the main body part 231 and at least one tab 232. The tab 232 includes a plurality of sub-tabs extending from one end of the main body part 231 and stacked, and the plurality of sub-tabs are welded to form a welded part 2321, and the welded part 2321 includes a thinning area 2321A configured to be recessed relative to the surface of the welded part 2321 and form at least one recess 2321a for electrically connecting the electrode terminal 22. The recess 2321a can effectively reduce the thickness of part of the tab 232, and the electrical connection between the tab 232 and the electrode terminal 22 is more reliable.

[0168] The laser welding between the thinning area of the tab and the electrode terminal is described in detail below through specific embodiments.

[0169] Embodiment 1

[0170] The negative tab and the first electrode terminal are connected by laser welding and form a welding spot, wherein the power of the laser welding is 4000W, the material of the negative tab is copper, and the thickness of the thinning area of the negative tab is 0.4mm.

[0171] Example 2

[0172] The difference from Example 1 is that the thickness of the thinning area is 0.6 mm.

[0173] Example 3

[0174] The difference from Example 1 is that the thickness of the thinning area is 0.8 mm.

[0175] Example 4

[0176] The difference from Example 1 is that the thickness of the thinning area is 1.0 mm.

[0177] Example 5

[0178] The difference from Example 1 is that the thickness of the thinning area is 1.2 mm.

[0179] Example 6

[0180] The positive electrode tab and the second electrode terminal are connected by laser welding and a weld is formed, wherein the power of the laser welding is 2500 W, the material of the positive electrode tab is aluminum, and the thickness of the thinning area of the positive electrode tab is 0.6 mm.

[0181] Example 7

[0182] The difference from Example 6 is that the thickness of the thinning area is 0.8 mm.

[0183] Example 8

[0184] The difference from Example 6 is that the thickness of the thinning area is 1.0 mm.

[0185] Example 9

[0186] The difference from Example 6 is that the thickness of the thinning area is 1.2 mm.

[0187] Example 10

[0188] The difference from Example 6 is that the thickness of the thinning area is 1.4 mm.

[0189] The appearance of the welds formed in Examples 1-10 is observed, and the results are shown in Table 1.

[0190] Table 1

[0191]

[0192]

[0193] According to Table 1, the thinning area can thin the tab, which can reduce the risk of virtual welding of the thinning area and the electrode terminal laser welding.

[0194] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced equivalently. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application. In particular, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An electrode assembly, characterized by, The electrode assembly comprises: a body portion; at least one tab comprising a plurality of sub-tabs extending from one end of the body portion and arranged in a stack, the plurality of sub-tabs being welded together and forming a welded portion, the welded portion comprising a thinned region, the thinned region having a thickness less than a maximum thickness of the welded portion, the tab comprising a connecting portion connected between the body portion and the welded portion, and in the connecting portion, the plurality of sub-tabs are arranged to be separable.

2. The electrode assembly of claim 1, wherein, The thinned region is configured to be recessed relative to at least one surface of the welded portion and form at least one recess.

3. The electrode assembly of claim 2, wherein, In a thickness direction of the welded portion, a ratio of a depth of the recess to the maximum thickness of the welded portion is in a range of 0.3-0.

7.

4. The electrode assembly of claim 2, wherein, In the thickness direction of the welded portion, a thickness of a bottom wall of the recess is less than or equal to 2mm.

5. The electrode assembly of claim 2, wherein, The recess is a contoured recess, a shape of the contoured recess is adapted to a path for electrically connecting the thinned region and an electrode terminal of a battery cell.

6. The electrode assembly of claim 5, wherein, The shape of the contoured recess is annular.

7. The electrode assembly of claim 5, wherein, The shape of the contoured recess is strip-shaped.

8. The electrode assembly of claim 5, wherein, The number of the contoured recesses is a plurality.

9. The electrode assembly of any one of claims 2-8, wherein, A surface of the welded portion comprises a first surface and a second surface oppositely arranged along the thickness direction of the welded portion, the recess is formed in the first surface, and the second surface is used for electrically connecting the electrode terminal.

10. The electrode assembly of any one of claims 2-8, wherein, The recess is formed by stamping or swaging.

11. The electrode assembly of any one of claims 1-8, wherein, In an extension direction of the tab, a ratio of a size of the welded portion to a total size of the tab is in a range of 0.2-0.

8.

12. The electrode assembly of any one of claims 1-8, wherein, In the extension direction of the tab, the size of the welded portion is 5mm-10mm.

13. The electrode assembly of any one of claims 1-8, wherein, The plurality of sub-tabs are ultrasonically welded to form the welded portion.

14. The electrode assembly of any one of claims 1-8, wherein, The electrode assembly further comprises an insulating member, and the welded portion further comprises a non-thinned region, and the insulating member is arranged on at least one surface of the connecting portion and the non-thinned region.

15. The electrode assembly of any one of claims 1-8, wherein, The at least one tab comprises: a first tab, a thinned region of the first tab being configured to electrically connect a first electrode terminal of a battery cell; a second tab, opposite in polarity to the first tab, a thinned region of the second tab being configured to electrically connect a second electrode terminal of the battery cell, the second electrode terminal and the first electrode terminal being opposite in polarity.

16. A battery cell, characterized by The battery cell comprises: a housing; an electrode terminal arranged in the housing; the electrode assembly of any one of claims 1-15 is accommodated in the housing, and the thinned region is electrically connected to the electrode terminal.

17. The battery cell of claim 16, wherein, The thinned region and the electrode terminal are connected by laser welding and form a weld.

18. A battery, characterized by The battery cell of claim 16 or 17 is included.

19. An electrical device, comprising: The battery of claim 18 is used to provide electrical energy.

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