Battery monomer, battery device, energy storage device and power utilization device

Abstract

The utility model is applicable to the technical field of batteries, and provides a single battery, a battery device, an energy storage device and a power utilization device.The single battery comprises a shell and an electrode assembly contained in the shell, the electrode assembly comprises a first pole piece, a second pole piece and an isolating membrane, and the first pole piece and the second pole piece are opposite in polarity and are wound in the winding direction; the isolating membrane is arranged between the first pole piece and the second pole piece; the first pole piece comprises a first winding part and a second winding part, each of the first winding part and the second winding part comprises two first straight parts which are oppositely arranged and two first corner parts which are oppositely arranged, the first straight parts are connected with the first corner parts, first tabs are arranged on the two first straight parts of the first winding part, and second tabs are arranged on the second straight parts of the second winding part. And a first tab is arranged on a first straight part of the second winding part. The battery cell provided by the embodiment of the utility model can reduce the risk of lithium precipitation.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a battery cell, a battery device, an energy storage device, and an electrical device. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] The lithium batteries used in electric vehicles are generally referred to as power batteries. A single cell in a power battery typically includes a casing, electrode components, and electrolyte, with the electrolyte and electrode components sealed within the casing. However, in some cases, there is a risk of lithium plating in certain areas of the electrode components. Utility Model Content

[0004] In view of this, embodiments of this application provide a battery cell, a battery device, an energy storage device, and an electrical device, which can reduce the risk of lithium plating in electrode components.

[0005] An embodiment of the first aspect of this application provides a battery cell, comprising: a housing; an electrode assembly housed within the housing, the electrode assembly including a first electrode, a second electrode, and a separator, the first electrode and the second electrode having opposite polarities and being wound along a winding direction, the separator being disposed between the first electrode and the second electrode; the first electrode including a first winding portion and a second winding portion, each of the first winding portion and the second winding portion including two oppositely arranged first straight portions and two oppositely arranged first corner portions, the first straight portions being connected to the first corner portions, each of the two first straight portions of the first winding portion being provided with a first tab, and one of the first straight portions of the second winding portion being provided with a first tab.

[0006] The battery cell provided in this application includes a casing and an electrode assembly housed within the casing. The electrode assembly includes a first electrode and a second electrode wound together, and a separator disposed between the first electrode and the second electrode. The first electrode includes a first winding portion and a second winding portion. Each of the two first straight portions of the first winding portion is provided with a first tab, i.e., the first winding portion is provided with multiple first tabs. Multiple first tabs can be used to achieve parallel current splitting, so that the current can be more evenly distributed on the first winding portion during high current charging and discharging, thereby improving the overcurrent capacity and conductivity of the first winding portion, and thus reducing the risk of lithium plating of the electrode assembly. Furthermore, since the first winding portion is provided with multiple first tabs, when one first tab is torn, the first winding portion can still use another first tab for overcurrent, thereby not affecting the charging and discharging function of the electrode assembly, enhancing the structural stability of the electrode assembly, and reducing the risk of lithium plating caused by tab tearing.

[0007] In some embodiments, the first winding portion is disposed on the inner ring of the second winding portion.

[0008] By adopting the above technical solution, the battery cell provided in this application embodiment improves the conductivity of the first winding portion and alleviates the problem of lithium plating in the inner ring.

[0009] In some embodiments, the first winding portion begins to wind from the starting end of the first electrode sheet, and the number of turns of the first winding portion is 1 to 3.

[0010] By adopting the above technical solution, even if the first tab of the inner ring tears during welding, the first tab of the first winding portion in the same ring can still carry current, without affecting the charging and discharging performance of the electrode assembly, thus improving the problem of lithium plating in the inner ring. In addition, the second winding portion maintains one first tab, which prevents the thickness of multiple first tabs from becoming too large, thereby increasing the welding difficulty and the space occupied.

[0011] In some embodiments, a plurality of first tabs are stacked.

[0012] By adopting the above technical solution, multiple first tabs can be connected to the same electrode terminal, which improves the manufacturing efficiency of battery cells, reduces the cost of battery cells, and makes the structure of battery cells more compact, which is conducive to improving the energy density of battery devices.

[0013] In some embodiments, on a first side of the first electrode starting end of the first electrode, a plurality of first straight portions are provided with first tabs; on a second side of the first electrode starting end of the first electrode, at least one first straight portion is provided with a first tab, and the first side and the second side are arranged opposite to each other along the thickness direction of the electrode assembly.

[0014] By adopting the above technical solution, the manufacturing difficulty of the first electrode sheet is relatively small, and the multiple first electrode tabs on the first side can be closer to the components to be welded, reducing the risk of incomplete soldering during the welding of the first electrode tabs and improving the welding reliability.

[0015] In some embodiments, the second electrode includes a multi-turn third winding portion, and a single-turn third winding portion includes two oppositely arranged second straight portions and two oppositely arranged second corner portions, with the second straight portions and the second corner portions connected together; each turn of the second winding portion is provided with a second electrode tab on one of the second straight portions; the first electrode is an anode plate, and the second electrode is a cathode plate.

[0016] By adopting the above technical solution, the number of tabs in the first winding part of the anode sheet is increased, which improves the conductivity of the anode sheet and reduces the risk that lithium ions cannot be embedded in the anode sheet, thus reducing the risk of lithium plating.

[0017] In some embodiments, the second electrode includes a third winding portion and a fourth winding portion, each of which includes two oppositely arranged second straight portions and two oppositely arranged second corner portions, the second straight portions being connected to the second corner portions; each of the two second straight portions of the third winding portion is provided with a second electrode tab, and one of the second straight portions of the fourth winding portion is provided with a second electrode tab.

[0018] By adopting the above technical solution, the overcurrent capacity and conductivity of the third winding section can be improved to reduce the risk of lithium plating; and, when one of the second tabs is torn, the third winding section can also use the overcurrent of the other second tab, which also reduces the risk of lithium plating of the electrode assembly.

[0019] In some embodiments, the third winding portion is disposed on the inner ring of the fourth winding portion.

[0020] By adopting the above technical solution, the electrode assembly can improve the problem of lithium plating in the inner ring.

[0021] In some embodiments, the third winding portion begins to wind from the starting end of the second electrode sheet, and the number of turns of the third winding portion is 1 to 3.

[0022] By adopting the above technical solution, even if the second tab of the inner ring tears during welding, the second tab of the same ring can still carry current without affecting the charging and discharging performance of the electrode assembly, thus improving the problem of lithium plating in the inner ring. In addition, the fourth winding section maintains only one second tab, which prevents the thickness of multiple second tabs from becoming too large, thereby increasing the welding difficulty and the space occupied.

[0023] In some embodiments, the two first straight portions of the first winding portion are provided with first pole tabs at their opposite ends along the first direction, and the first straight portion of the second winding portion is provided with first pole tabs at their opposite ends along the first direction, the first direction being parallel to the width direction of the first pole piece; the two second straight portions of the third winding portion are provided with second pole tabs at their opposite ends along the first direction, and the second straight portion of the fourth winding portion is provided with second pole tabs at their opposite ends along the first direction.

[0024] By adopting the above technical solution and increasing the number of tabs, the conductivity of the electrode assembly is further improved.

[0025] In some embodiments, the housing has two end caps disposed opposite to each other, one end cap having a first electrode terminal and a second electrode terminal, and the other end cap having a third electrode terminal and a fourth electrode terminal; the first tabs at opposite ends of the first straight portion are electrically connected to the first electrode terminal and the third electrode terminal, respectively, and the second tabs at opposite ends of the second straight portion are electrically connected to the second electrode terminal and the fourth electrode terminal, respectively.

[0026] By adopting the above technical solution, the two end caps of the battery cell respectively have electrode terminals, and the battery cell can output current from the electrode terminals at both ends.

[0027] An embodiment of the second aspect of this application provides a battery device including a battery cell as described in the first aspect.

[0028] An embodiment of the third aspect of this application provides an energy storage device, including a plurality of battery cells as in the first aspect or a plurality of battery devices as in the second aspect, wherein the battery cells or battery devices are used to store or provide electrical energy.

[0029] An embodiment of the third aspect of this application provides an electrical device, including a battery cell as in the first aspect, a battery device as in the second aspect, or an energy storage device as in the third aspect, wherein the battery cell or battery device is used to store or provide electrical energy.

[0030] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application;

[0033] Figure 2 This is an exploded view of a battery device provided in an embodiment of this application;

[0034] Figure 3 This is an exploded view of a single battery cell provided in an embodiment of this application;

[0035] Figure 4 This is one of the structural schematic diagrams of an electrode assembly provided in an embodiment of this application;

[0036] Figure 5 This is a partial structural schematic diagram of the first electrode provided in an embodiment of this application;

[0037] Figure 6 This is a partial structural schematic diagram of the second electrode provided in an embodiment of this application;

[0038] Figure 7This is a second schematic diagram of the structure of the electrode assembly provided in one embodiment of this application;

[0039] Figure 8 This is the third schematic diagram of the structure of the electrode assembly provided in one embodiment of this application;

[0040] Figure 9 This is a schematic diagram of the structure of an electrode assembly provided in another embodiment of this application;

[0041] Figure 10 This is a schematic diagram of the structure of a battery cell provided in another embodiment of this application.

[0042] The markings in the diagram mean:

[0043] 1000, vehicles;

[0044] 100. Battery; 10. Box; 11. Upper box; 12. Lower box;

[0045] 20. Battery cell;

[0046] 21. Electrode assembly;

[0047] 211, First pole piece; 2111, First winding section; 2112, Second winding section; 211a, First straight section; 211b, First corner section; 2113, First pole lug; 2114, First main body section;

[0048] 212. Second pole piece; 2121. Third winding section; 2122. Fourth winding section; 212a. Second straight section; 212b. Second corner section; 2123. Second pole lug; 2124. Second main body section;

[0049] 213. Separating membrane;

[0050] 22. Outer shell; 221. Housing; 222. End cap; 2221. First electrode terminal; 2222. Second electrode terminal; 2223. Third electrode terminal; 2224. Fourth electrode terminal;

[0051] 23. Adapter plate. Detailed Implementation

[0052] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0053] 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 pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0054] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0055] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0056] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0057] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0058] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0059] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0060] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0061] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0062] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0063] A single battery cell in a power battery typically includes a casing, electrode assembly, and electrolyte. The electrolyte and electrode assembly are sealed inside the casing. In the design of electrode assembly, the winding method is a commonly used method.

[0064] During charging, lithium ions are extracted from the cathode and inserted into the anode. However, when abnormal conditions occur that prevent the extracted lithium ions from embedding into the anode, they precipitate onto the anode surface, forming a gray layer – this is known as lithium plating. Lithium plating directly affects the battery's cycle life, and a vicious cycle can pose significant safety hazards.

[0065] For wound electrode assemblies, there is a greater risk of lithium plating in certain areas, for example, due to lithium plating caused by tab tearing.

[0066] In view of this, embodiments of this application provide a battery cell that can reduce the risk of lithium plating in the electrode assembly. The battery cell includes a housing and an electrode assembly housed within the housing. The electrode assembly includes a first electrode, a second electrode, and a separator. The first and second electrodes have opposite polarities and are wound along the winding direction. The separator is disposed between the first and second electrodes. The first electrode includes a first winding portion and a second winding portion. Each first winding portion includes two oppositely arranged first straight portions and two oppositely arranged first corner portions. The first corner portions are connected to the first straight portions. Each of the two first straight portions of the first winding portion is provided with a first tab. One of the first straight portions of the second winding portion is provided with a first tab.

[0067] In the aforementioned battery cell, each of the two first straight sections of the first winding portion is provided with a first tab, meaning that the first winding portion has two or more first tabs. By increasing the number of first tabs on the first winding portion, at least two first tabs can be used to achieve parallel current splitting, allowing the current to be more evenly distributed on the first winding portion during high-current charging and discharging. This improves the overcurrent capacity and conductivity of the first winding portion, thereby reducing the risk of lithium plating in the electrode assembly. Furthermore, since the first winding portion has multiple first tabs, if one first tab is torn, the first winding portion can still use another first tab for overcurrent, thus not affecting the charging and discharging function of the electrode assembly, enhancing the structural stability of the electrode assembly, and reducing the risk of lithium plating in the electrode assembly.

[0068] The battery device disclosed in this application can be used in electrical devices that use the battery device as a power source or in various energy storage systems that use the battery device as an energy storage element. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0069] The energy storage device provided in this application includes one or more battery clusters to improve the voltage and capacity of the energy storage device. A battery cluster may include multiple battery devices, which are connected in series via a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, the multiple battery clusters are connected in parallel to increase the capacity of the energy storage device.

[0070] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, an energy storage device can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours. The energy storage system provided in this application embodiment can be any power system that requires energy storage devices.

[0071] In some embodiments, the energy storage device is an energy storage container or an energy storage cabinet.

[0072] In some embodiments, the energy storage device may include a cabinet and one or more battery clusters housed within the cabinet.

[0073] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0074] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0075] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0076] refer to Figure 2 , Figure 2 This is an exploded structural diagram of a battery device 100 provided in some embodiments of this application. The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells 20, which are connected in series, parallel, or mixed connections via busbars.

[0077] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells 20; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells 20 together to form an independent module. As an example, a battery module can be formed by bundling multiple battery cells 20 together with cable ties.

[0078] In some embodiments, the battery device 100 may be a battery pack, which includes a housing 10 and one or more individual battery cells housed within the housing 10.

[0079] As an example, the battery cell assembly can be a battery module, which can be housed in the housing by fixing the battery module in the housing 10.

[0080] As an example, the battery cell assembly can also be housed in the housing 10 by directly fixing multiple battery cells 20 to the housing 10.

[0081] As an example, the housing 10 may include an upper housing 11 and a lower housing 12. The upper housing 11 and the lower housing 12 are fastened together, forming a closed receiving cavity inside the housing 10 to house the battery cell assembly. Here, "closed" refers to covering or closing, and can be either sealed or unsealed.

[0082] As an example, the housing 10 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that the interior of the housing 10 forms a closed receiving cavity to house the battery cell assembly 20.

[0083] As an example, the housing 10 can be part of the chassis structure of the vehicle 1000. For example, the top cover of the housing 10 can be at least part of the floor of the vehicle 1000, or the frame of the housing 10 can be at least part of the crossbeams and longitudinal beams of the vehicle 1000.

[0084] In some embodiments, battery device 100 refers to an energy storage device, which includes a housing 10, and at least one side of the housing 10 has a door. The energy storage device includes energy storage containers, energy storage cabinets, etc.

[0085] Figure 3 This is an exploded view of a battery cell 20 provided in one embodiment of this application. Please refer to... Figure 3 Battery cell 20 refers to the smallest unit that makes up the battery device. Battery cell 20 includes electrode assembly 21, casing 22 and electrolyte. Electrode assembly 21 and electrolyte are both contained in casing 22.

[0086] The outer casing 22 includes a housing 221 and an end cap 222. The end cap 222 is a component that covers the opening of the housing 221 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 222 can be adapted to the shape of the housing 221 to fit the housing 221. Optionally, the end cap 222 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 222 is not easily deformed when subjected to compression and impact, so that the battery cell 20 can have higher structural strength and improved safety performance. Functional components such as electrode terminals and explosion-proof valves can be provided on the end cap 222. The electrode terminals can be used to electrically connect with the electrode assembly 21 for outputting or inputting electrical energy of the battery cell 20. In some embodiments, the end cap 222 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The end cap 222 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating element may also be provided on the inner side of the end cap 222 to reduce the risk of short circuit. For example, the insulating element may be plastic, rubber, etc.

[0087] The housing 221 is a component used to cooperate with the end cap 222 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 21, electrolyte, and other components. The housing 221 and the end cap 222 can be independent components. An opening can be provided on the housing 221, and the end cap 222 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 222 and the housing 221 can be integrated. Specifically, the end cap 222 and the housing 221 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 221, the end cap 222 closes the housing 221. The housing 221 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 221 can be determined according to the specific shape and size of the electrode assembly 21. The material of the housing 221 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special limitations on this.

[0088] Electrode assembly 21 is the component in the battery cell 20 where the electrochemical reaction occurs. The casing 221 may contain one or more electrode assemblies 21. The electrode assembly 21 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly 21, while the portions of the positive and negative electrode sheets without active material each constitute a tab. The positive and negative tabs may be located together at one end of the electrode body or separately at both ends of the electrode body. During the charging and discharging process of the battery device 100, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals to form a current loop.

[0089] An embodiment of the first aspect of this application provides a battery cell 20. Figure 4 This is one of the structural schematic diagrams of the electrode assembly 21 provided in an embodiment of this application. Please refer to... Figure 3 and Figure 4 The battery cell 20 includes a housing 22 and an electrode assembly 21 housed within the housing 22. The electrode assembly 21 includes a first electrode 211, a second electrode 212, and a separator 213. The first electrode 211 and the second electrode 212 have opposite polarities and are wound along the winding direction. The separator 213 is disposed between the first electrode 211 and the second electrode 212. The first electrode 211 includes a first winding portion 2111 and a second winding portion 2112. Both the first winding portion 2111 and the second winding portion 2112 include two oppositely arranged first straight portions 211a and two oppositely arranged first corner portions 211b. The first straight portions 211a and the first corner portions 211b are connected. The two first straight portions 211a of the first winding portion 2111 are each provided with a first tab 2113. The first straight portion 211a of the second winding portion 2112 is provided with a first tab 2113.

[0090] The electrode assembly 21 includes a first electrode 211, a second electrode 212, and a separator 213 wound together, that is, the electrode assembly 21 is a wound electrode assembly. The first electrode 211 and the second electrode 212 have opposite polarities, and one of the first electrode 211 and the second electrode 212 is a cathode and the other is an anode.

[0091] The battery cell 20 mainly relies on the movement of metal ions between the cathode and anode plates to work. The separator 213 is an insulating film used to separate the cathode and anode plates and prevent short circuits between them. The material of the separator 213 can be PP (polypropylene) or PE (polyethylene), etc.

[0092] The cathode (also called the positive electrode) includes a cathode current collector and a cathode active material disposed on at least one surface of the cathode current collector. Taking a lithium-ion battery cell as an example, the cathode current collector can be made of aluminum, and the cathode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The anode (also called the negative electrode) includes an anode current collector and an anode active material disposed on at least one surface of the anode current collector. The anode current collector can be made of copper, and the anode active material can be carbon or silicon, etc.

[0093] The cross-sectional shape of the electrode assembly 21 is approximately a rectangle with rounded edges. Compared to a rectangle, the shorter side of this rectangle is a semi-circular arc or approximately a semi-circular arc. The first electrode 211 includes a first winding portion 2111 and a second winding portion 2112. Both the first winding portion 2111 and the second winding portion 2112 are formed by winding the first electrode 211 one turn. The number of the first winding portion 2111 and the second winding portion 2112 can be one or more. Each single-turn first winding portion 2111 and single-turn second winding portion 2112 includes two oppositely arranged first straight portions 211a and two oppositely arranged first corner portions 211b. The two first straight portions 211a are substantially parallel, and the two first corner portions 211b are respectively located at opposite ends of the first straight portions 211a. The first corner portion 211b is the corner part of the first electrode 211 in the winding structure. The first corner portion 211b is bent. The first corner portion 211b may have a curved surface or a bend. A bend refers to a bend with a certain angle, which can be an acute angle, a right angle, an obtuse angle, or other angles and combinations thereof.

[0094] Each of the two first straight portions 211a of the first winding portion 2111 is provided with a first electrode tab 2113, that is, in the first winding portion 2111, each of the two first straight portions 211a is provided with at least one first electrode tab 2113. For example, each first straight portion 211a is in the height direction of the electrode assembly 21 ( Figure 3 A first electrode tab 2113 is provided at one end of the first straight portion 211a in the Z-direction, or a first electrode tab 2113 is provided at both ends of the first straight portion 211a in the height direction of the electrode assembly 21. Thus, a plurality of first electrode tabs 2113 are provided on the first winding portion 2111. A first electrode tab 2113 is provided on one first straight portion 211a of the second winding portion 2112, while no first electrode tab 2113 is provided on the other first straight portion 211a.

[0095] like Figure 4As shown, in some embodiments, the first electrode 211 is an anode and the second electrode 212 is a cathode, or the first electrode 211 is a cathode and the second electrode 212 is an anode. The first electrode 211 includes three turns of first winding portion 2111 and multiple turns of second winding portion 2112. Each of the two first straight portions 211a of the first winding portion 2111 is provided with a first electrode tab 2113, and one straight portion 211a of the second winding portion 2112 is provided with a first electrode tab 2113. Optionally, the second electrode 212 includes multiple turns of third winding portion 2121, and the three turns of third winding portion 2121 located in the inner circle of the electrode assembly 21 are each provided with two second electrode tabs 2123.

[0096] It is understood that the first winding portion 2111, which has multiple first tabs 2113, can have one, two, three, or more turns. The first winding portion 2111 can be located on the inner or outer ring of the electrode assembly 21. In order to reduce the risk of lithium plating, it is preferable to place the first winding portion 2111 in a position with a higher risk of lithium plating.

[0097] In related technologies, the main function of the tab is to connect the electrode sheet to the electrode terminal to transmit electrical energy. In some existing cases, only one tab is provided per turn of the electrode sheet, and multiple turns of tabs are electrically connected to one electrode terminal. Compared with the related technologies, in the electrode assembly 21 of this application embodiment, multiple first tabs 2113 are provided on the first winding portion 2111. By increasing the number of first tabs 2113, the current carrying capacity and conductivity of the first winding portion 2111 can be improved, and the risk of lithium plating can be reduced.

[0098] The battery cell 20 provided in this embodiment includes a housing 22 and an electrode assembly 21 housed within the housing 22. The electrode assembly 21 includes a first electrode 211 and a second electrode 212 wound together, and a separator 213 disposed between the first electrode 211 and the second electrode 212. The first electrode 211 includes a first winding portion 2111 and a second winding portion 2112. Each of the two first straight portions 211a of the first winding portion 2111 is provided with a first tab 2113, that is, the first winding portion 2111 is provided with a plurality of first tabs 2113, which can be used to achieve parallel connection. The current shunting allows the current to be distributed more evenly on the first winding portion 2111 during high-current charging and discharging, thereby improving the overcurrent capacity and conductivity of the first winding portion 2111 and reducing the risk of lithium plating in the electrode assembly 21. Furthermore, since the first winding portion 2111 is provided with multiple first tabs 2113, if one first tab 2113 is torn, the first winding portion 2111 can still use another first tab 2113 to carry the current, thus not affecting the charging and discharging function of the electrode assembly 21, enhancing the structural stability of the electrode assembly 21, and reducing the risk of lithium plating caused by tab tearing.

[0099] In some embodiments, the first winding portion 2111 is disposed on the inner ring of the second winding portion 2112.

[0100] The first winding portion 2111 is disposed within the inner circle of the second winding portion 2112, that is, the second winding portion 2112 is wound around the outside of the first winding portion 2111. The first winding portion 2111 may have one or more turns, wherein the multiple turns of the first winding portion 2111 may be arranged continuously or at intervals. Please refer to... Figure 4 In some embodiments, the three first winding portions 2111 are connected sequentially, and all three first winding portions 2111 are located within the inner ring of the second winding portion 2112; please refer to Figure 7 In other embodiments, two turns of the first winding portion 2111 are spaced apart, and the two turns of the first winding portion 2111 are located within the multiple turns of the second winding portion 2112. The number of the first winding portions 2111 can be flexibly set. In some embodiments, the number of the first winding portions 2111 can be 1, 2, 3, 4, 5, 8, 10, etc., which can be specifically set according to the risk of lithium plating.

[0101] The inner electrode may suffer from lithium plating due to tab tearing, or the electrode at the corner may have a large curvature, resulting in excessive stress and potentially causing active material shedding and brittle fracture, thus leading to lithium plating. By providing multiple first tabs 2113 on the first winding portion 2111 and placing the first winding portion 2111 in the inner ring of the second winding portion 2112, the electrode assembly 21 can improve the problem of lithium plating in the inner ring of the electrode assembly 21.

[0102] On the one hand, by providing multiple first tabs 2113 on the first winding portion 2111, the conductivity of the first winding portion 2111 can be improved, the lithium insertion capability of the electrode assembly 21 can be enhanced, and the risk of lithium plating caused by the active material falling off and brittle fracture of the electrode at the inner corner can be reduced.

[0103] On the other hand, after fabricating the electrode assembly 21, multiple first tabs 2113 can be welded to the adapter piece 23, and the adapter piece 23 is welded to the first electrode terminal 2221. During the ultrasonic welding process of the multiple first tabs 2113 and the adapter piece 23, the welding head is located on the side of the first tab 2113 away from the adapter piece 23. In some cases, each turn of the electrode sheet has one tab, and multiple tabs are located on the same side of the virtual axis. Since the tabs of a single sheet are relatively thin, during the welding process, power fluctuations may cause one or more layers of tabs near the welding head to tear, that is, the inner ring tabs to tear, which in turn increases the internal resistance of the electrode sheet at the tear or causes an open circuit, resulting in lithium plating problems in the electrode assembly 21 due to tab tearing. According to the embodiments provided in this application, in the first winding portion 2111, even if one first tab 2113 tears due to welding or other problems, the other first tab 2113 can still allow current to pass through. The electrode assembly 21 described above reduces the risk of lithium plating caused by the tearing of the inner ring first tab 2113.

[0104] It is understood that the adapter piece 23 can be omitted, and multiple first tabs 2113 can be welded to the electrode terminals. The first tabs 2113 still have the risk of welding tearing. The battery cell 20 provided in this application embodiment can also alleviate the risk of lithium plating caused by welding tearing of the first tabs 2113.

[0105] Therefore, in this embodiment, the first winding portion 2111 is disposed in the inner ring of the second winding portion 2112, which improves the problem that the inner ring of the electrode assembly 21 is prone to lithium plating.

[0106] In other embodiments, the first winding portion 2111 may also be located in an area on the outer ring where there is a higher risk of lithium plating.

[0107] In some embodiments, the first winding portion 2111 starts winding from the winding start end of the first electrode 211, and the number of turns of the first winding portion 2111 is 1 to 3 turns.

[0108] The winding start end of the first electrode 211 refers to the end where the first electrode 211 begins to be wound. The electrode assembly 21 is wound around a virtual axis, and the winding start end is the end close to the virtual axis of the electrode assembly 21. The first electrode 211 also has a winding end set along the winding direction.

[0109] by Figure 4 For example, Figure 4 Point P1 is the starting point of the winding of the first electrode 211. Along the winding direction, the first electrode 211 between point P1 and point P2 is the first winding portion 2111 of the first turn.

[0110] The first winding portion 2111, which starts from the winding start end of the first electrode 211, can start from the first straight portion 211a or from the first corner portion 211b. In some embodiments, the length of the first straight portion 211a closest to the winding start end is short or, for other reasons, it is not possible to set the first tab 2113 on the first straight portion 211a. In this case, the first winding portion 2111 of the first turn includes not only the two first straight portions 211a and the two first winding portions 211b, but also the winding end located in the innermost circle of the electrode assembly 21. The first winding portion 2111 of the first turn can still set the first tab 2113 on the two first straight portions 211a respectively.

[0111] In some embodiments, the number of first winding portions 2111 is 1 to 3 turns. For example, if the number of first winding portions 2111 is 3 turns, then in the first winding portions 2111 of the 1st to 3rd turns, the first tabs 2113 are provided on the first straight portions 211a on both sides of the virtual winding axis, and the first tabs 2113 are provided only on the first straight portion 211a on one side of the virtual winding axis in the second winding portion 2112.

[0112] In this embodiment, multiple first tabs 2113 are provided on the first winding portion 2111, which is wound from the starting end of the winding. This increases the number of first tabs 2113 on the inner ring of the electrode assembly 21. Even if the first tabs 2113 on the inner ring tear during welding, the first tabs 2113 on the same ring can still carry current, without affecting the charge and discharge performance of the electrode assembly 21, thus improving the problem of lithium plating on the inner ring. In addition, the second winding portion 2112 maintains only one first tab 2113, which prevents the thickness of multiple first tabs 2113 from becoming too large, thus avoiding increasing welding difficulty and space occupation.

[0113] In some embodiments, a plurality of first tabs 2113 are stacked.

[0114] Specifically, each of the two first straight sections 211a on the first winding section 2111 is provided with a first electrode tab 2113, and one of the first straight sections 211a on the second winding section 2112 is provided with a first electrode tab 2113. Multiple first electrode tabs 2113 are stacked and connected to each other to form a first electrode tab section. The first electrode tab section is electrically connected to the first electrode terminal 2221 on the housing 22. Optionally, the first electrode tab section is welded to the first electrode terminal 2221, or the first electrode tab 2113 is welded to the adapter piece 23 and electrically connected to the first electrode terminal 2221 through the adapter piece 23.

[0115] Please refer to Figure 4 and Figure 5The first tabs 2113 on the first electrode sheet 211 are arranged opposite to each other and stacked. The first tabs 2113 can be die-cut onto the first electrode sheet 211, or the first tabs 2113 can be welded to the first electrode sheet 211. The first electrode sheet 211 includes a first main body portion 2114 and a plurality of first tabs 2113 disposed on one side of the first main body portion 2114. The first main body portion 2114 includes a current collector and an active material disposed on the surface of the current collector. The first main body portion 2114 is used to wind into a plurality of first straight portions 211a and a plurality of first corner portions 211b. After the first electrode sheet 211 is manufactured and before winding, the first electrode sheet 211 is provided with a plurality of first tabs 2113, wherein the distance between at least two first tabs 2113 is smaller than the distance between other two adjacent first tabs 2113, and two first tabs 2113 that are closer together can be located on two first straight portions 211a of the same turn of the first winding portion 2111.

[0116] By stacking multiple first tabs 2113, multiple first tabs 2113 can be connected to the same electrode terminal without increasing the number of electrode terminals, which improves the manufacturing efficiency of the battery cell 20 and reduces the cost of the battery cell 20. At the same time, the stacking of the first tabs 2113 can also make the structure of the battery cell 20 more compact, which is beneficial to improving the energy density of the battery device 100.

[0117] Please refer to Figure 4 In some embodiments, on the first side of the first electrode 211 at the starting end of the winding, a plurality of first straight portions 211a are provided with first tabs 2113 respectively; on the second side of the first electrode 211 at the starting end of the winding, at least one first straight portion 211a is provided with a first tab 2113, and the first side and the second side are arranged opposite to each other along the thickness direction of the electrode assembly 21.

[0118] "First side" and "second side" are relative to the winding start end of the first electrode 211, along the thickness direction of the electrode assembly 21. Figure 4 The two sides are relatively distributed in the Y direction.

[0119] by Figure 4 For example, on the first side of the winding start end of the first electrode 211, a plurality of first straight portions 211a are provided with first electrode tabs 2113; on the second side of the winding start end of the first electrode tabs 2113, only the first straight portions 211a of the first and second turns are provided with first electrode tabs 2113; the plurality of first electrode tabs 2113 are stacked. Please refer to Figure 4 and Figure 5When manufacturing the first electrode 211, only a portion of the first electrode 211 needs to have its number of first tabs 2113 increased; the remaining portions can still have equally spaced first tabs 2113, making the manufacturing of the first electrode 211 relatively easy. Furthermore, during the soldering of the first tabs 2113 to the adapter 23 or the first electrode terminal 2221, the first tabs 2113 on the first side are closer to the adapter 23 or the first electrode terminal 2221 than the second tabs 2123 on the second side, reducing the risk of poor soldering.

[0120] By adopting the above technical solution, the manufacturing difficulty of the first electrode 211 is relatively small, and the multiple first electrode tabs 2113 on the first side can be closer to the components to be soldered, reducing the risk of cold solder joints when soldering the first electrode tabs 2113 and improving the soldering reliability.

[0121] Please refer to Figure 8 In some embodiments, the second electrode 212 includes a multi-turn third winding portion 2121, and a single-turn third winding portion 2121 includes two oppositely arranged second straight portions 212a and two oppositely arranged second corner portions 212b, with the second straight portions 212a and the second corner portions 212b connected; each turn of the third winding portion 2121 is provided with a second electrode tab 2123 on a second straight portion 212a; the first electrode 211 is an anode plate, and the second electrode 212 is a cathode plate.

[0122] The second straight portion 212a is arranged substantially parallel to the first straight portion 211a and is located in the straight region of the electrode assembly 21. The second corner portion 212b and the first corner portion 211b are both located in the corner region of the electrode assembly 21. The second corner portion 212b is bent, and may have a curved surface or a bend. In some embodiments, the second tab 2123 is provided in only one second straight portion 212a of each turn of the third winding portion 2121 of the second electrode 212. During the charging process of a lithium-ion battery, lithium ions are extracted from the cathode and inserted into the anode. However, when some abnormal conditions occur and the lithium ions extracted from the cathode cannot be inserted into the anode, the lithium ions can only be deposited on the surface of the anode, forming a layer of gray substance, which is the problem of lithium plating. Therefore, in the embodiments of this application, the number of tabs is increased in several first winding portions 2111 of the anode, which improves the conductivity of the anode and reduces the risk that lithium ions cannot be inserted into the anode, thus reducing the risk of lithium plating.

[0123] Please refer to Figure 4 and Figure 7In some embodiments, the second electrode 212 includes a third winding portion 2121 and a fourth winding portion 2122. Both the third winding portion 2121 and the fourth winding portion 2122 include two oppositely arranged second straight portions 212a and two oppositely arranged second corner portions 212b. The second straight portions 21 and the second corner portions 212b are connected. The two second straight portions 212a of the third winding portion 2121 are provided with second electrode tabs 2123, and one of the second straight portions 212a of the fourth winding portion 2122 is provided with a second electrode tab 2123.

[0124] The number of third winding portions 2121 and fourth winding portions 2122 can be one or more. Each of the two second straight portions 212a of the third winding portion 2121 is provided with a second pole tab 2123, that is, each of the two second straight portions 212a is provided with at least one second pole tab 2123. The second pole tab 2123 is provided on one side of the second straight portion 212a along the width direction of the second pole piece 212, or on both sides of the second straight portion 212a along the width direction of the second pole piece 212. Thus, the third winding portion 2121 is provided with multiple second pole tabs 2123.

[0125] It is understood that the third winding portion 2121, which has multiple second tabs 2123, can have one, two, three, or more turns. It is also understood that the third winding portion 2121, which has multiple second tabs 2123, can be located on the inner or outer ring of the electrode assembly 21. To reduce the risk of lithium plating, it is preferable to place multiple second tabs 2123 at locations with a higher risk of lithium plating.

[0126] Optionally, the second electrode tabs 2123 on the second electrode plate 212 are arranged opposite to and stacked. For example... Figure 6 As shown, the second tab 2123 can be die-cut onto the second electrode 212, or the second tab 2123 can be welded to the second electrode 212. The second electrode 212 includes a second main body 2124 and a plurality of second tabs 2123 disposed on one side of the second main body 2124. The second main body 2124 includes a current collector and an active material disposed on the surface of the current collector. The second main body 2124 is used to wind into a plurality of second straight portions 212a and a plurality of second corner portions 212b. After the second electrode 212 is manufactured and before winding, the second electrode 212 is provided with a plurality of second tabs 2123, wherein the distance between at least two second tabs 2123 is smaller than the distance between other two adjacent second tabs 2123, and the two second tabs 2123 that are closer together can be located in the two second straight portions 212a of a turn of the third winding portion 2121.

[0127] In the electrode assembly 21 of this application embodiment, a plurality of second tabs 2123 are provided on the third winding portion 2121. By increasing the number of second tabs 2123, the overcurrent capacity and conductivity of the third winding portion 2121 can be improved, thereby reducing the risk of lithium plating. Furthermore, when one second tab 2123 is torn, the third winding portion 2121 can also use another second tab 2123 for overcurrent, thereby not affecting the charging and discharging function of the electrode assembly 21, enhancing the structural stability of the electrode assembly 21, and reducing the risk of lithium plating of the electrode assembly 21.

[0128] In some embodiments, the third winding portion 2121 is disposed on the inner ring of the fourth winding portion 2122.

[0129] The third winding portion 2121 is disposed within the inner loop of the fourth winding portion 2122, meaning the fourth winding portion 2122 is wound around the outside of the third winding portion 2121. The third winding portion 2121 may have one or more turns, wherein multiple turns of the third winding portion 2121 may be arranged continuously or intermittently. Please refer to... Figure 4 In some embodiments, the three third winding portions 2121 are connected sequentially, and all three third winding portions 2121 are located within the inner ring of the fourth winding portion 2122; please refer to Figure 7 In other embodiments, two turns of the third winding 2121 are spaced apart, and the two turns of the third winding 2121 are located within the multiple turns of the fourth winding 2122. The number of the third windings 2121 can be flexibly set. In some embodiments, the number of the third windings 2121 can be 1, 2, 3, 4, 5, 8, 10, etc., which can be set according to the risk of lithium plating.

[0130] The inner electrode may suffer from lithium plating due to tab tearing, or the electrode at the corner may have a large curvature, resulting in excessive stress and potentially causing active material shedding and brittle fracture, thus leading to lithium plating. By providing multiple second tabs 2123 on the third winding portion 2121 and placing the third winding portion 2121 within the inner ring of the fourth winding portion 2122, the electrode assembly 21 can improve the problem of lithium plating in the inner ring of the electrode assembly 21.

[0131] In some embodiments, the third winding portion 2121 starts winding from the winding start end of the second electrode 212, and the number of turns of the third winding portion 2121 is 1 to 3 turns.

[0132] It should be noted that the first turn of the third winding portion 2121, which starts from the winding start end of the second electrode 212, can start from the second straight portion 212a or from the second corner portion 212b. In some embodiments, the first turn of the third winding portion 2121 starts from the second straight portion 212a. However, if the length of the second straight portion 212a is too short or other reasons prevent the second electrode tab 2123 from being provided on the second straight portion 212a closest to the winding start end, then it is considered that the first turn of the third winding portion 2121 starts from the second corner portion 212b, and the first turn of the third winding portion 2121 is provided with the second electrode tab 2123 on both of the two opposite second straight portions 212a.

[0133] In some embodiments, in the first to third winding portions 2121 that begin to wind from the starting end of the second pole piece 212, the second straight portion 212a is provided with a second pole tab 2123. For example, if the third winding portion 2121 is set to three turns, then in the third winding portion 2121 from the first to the third turn, the second straight portion 212a located on both sides of the virtual winding axis is provided with a second pole tab 2123. The fourth winding portion 2122 is provided with a second pole tab 2123 only on the second straight portion 212a on one side of the virtual winding axis.

[0134] By increasing the number of second tabs 2123 in the inner ring of the electrode assembly 21, even if the second tabs 2123 in the inner ring tear during welding, the second tabs 2123 in the same ring can still carry current without affecting the charge and discharge performance of the electrode assembly 21, thus improving the problem of lithium plating in the inner ring. In addition, the second tabs 2123 are arranged on a second straight surface in the fourth winding portion 2122, which prevents the thickness of multiple second tabs 2123 from becoming too large, thus avoiding increasing welding difficulty and space occupation.

[0135] Please refer to Figures 3 to 7 In some embodiments, the first tab 2113 and the second tab 2123 may be located on the same side of the electrode assembly 21 along its height direction, that is, the first straight portion 211a and the second straight portion 212a are provided with tabs on only one side. Please also refer to Figure 4 , Figure 7 , Figure 9 and Figure 10In other embodiments, the two first straight portions 211a of the first winding portion 2111 are provided with first tabs 2113 at their opposite ends along the first direction, and the first straight portion of the second winding portion 2112 is provided with first tabs 2113 at its opposite ends along the first direction, the first direction being parallel to the width direction of the first electrode 211; the two second straight portions 212a of the third winding portion 2121 are provided with second tabs 2123 at their opposite ends along the first direction, and the second straight portion 212a of the fourth winding portion 2122 is provided with second tabs 2123 at its opposite ends along the first direction.

[0136] The first direction is Figure 9 In the Z direction, the first direction is parallel to the width direction of the first electrode 211 and parallel to the height direction of the electrode assembly 21. In the first winding section 2111, the two first straight sections 211a are provided with first tabs 2113 at their opposite ends along the first direction Z. For example, from the winding start end of the first electrode 211, the two first straight sections 211a in the first winding section 2111 from the 1st turn to the 3rd turn are each provided with two first tabs 2113. In the second winding section 2112, only one first straight section 211a is provided with a first tab 2113 at its opposite ends along the first direction Z, and the other first straight section 211a is not provided with a first tab 2113.

[0137] In the third winding section 2121, each of the two second straight sections 212a is provided with a second pole tab 2123 at both ends along the first direction Z. For example, from the starting end of the winding of the second pole piece 212, each of the two second straight sections 212a in the third winding section 2121 from the first turn to the third turn is provided with two second pole tabs 2123. In the fourth winding section 2122, only one second straight section 212a is provided with a second pole tab 2123 at each end along the first direction Z, and the other second straight section 212a is not provided with a second pole tab 2123.

[0138] In the battery cell 20 provided in this application embodiment, two first tabs 2113 are provided on each of the two first straight portions 211a of the first winding portion 2111, and the two first tabs 2113 are arranged opposite each other along the first direction Z; two second tabs 2123 are provided on each of the two second straight portions 212a of the third winding portion 2121, and the two second tabs 2123 are arranged opposite each other along the first direction Z. In this way, by increasing the number of tabs, the conductivity of the electrode assembly 21 is further improved and the risk of lithium plating is reduced.

[0139] Please refer to Figure 9 and Figure 10The outer casing 22 has two end caps 222 arranged opposite to each other. One end cap 222 is provided with a first electrode terminal 2221 and a second electrode terminal 2222 with opposite polarities, and the other end cap 222 is provided with a third electrode terminal 2223 and a fourth electrode terminal 2224 with opposite polarities. The first tabs 2113 at opposite ends of the first straight portion 211a are electrically connected to the first electrode terminal 2221 and the third electrode terminal 2223, respectively. The second tabs 2123 at opposite ends of the second straight portion 212a are electrically connected to the second electrode terminal 2222 and the fourth electrode terminal 2224, respectively.

[0140] The outer casing 22 includes two end caps 222 and a housing 221 disposed between the two end caps 222. The battery cell 20 can have electrode terminals respectively exiting from the end caps 222 at opposite ends. One end cap 222 is provided with a first electrode terminal 2221 and a second electrode terminal 2222, and the other end cap 222 is provided with a third electrode terminal 2223 and a fourth electrode terminal 2224. The first tabs 2113 at opposite ends of the first straight portion 211a are electrically connected to the first electrode terminal 2221 and the third electrode terminal 2223, respectively. The second tabs 2123 at opposite ends of the second straight portion 212a are electrically connected to the second electrode terminal 2222 and the fourth electrode terminal 2224, respectively.

[0141] The two end caps 222 of the battery cell 20 respectively provide electrode terminals, and the battery cell 20 can output current from the electrode terminals at both ends; by increasing the number of tabs, the conductivity of the electrode assembly 21 is further improved, and the risk of lithium plating is reduced.

[0142] In other embodiments, the first electrode terminal 2221, the second electrode terminal 2222, the third electrode terminal 2223, and the fourth electrode terminal 2224 may also be disposed on the end cap 222 or side wall on the same side of the housing 22.

[0143] Please refer to Figure 3 and Figure 4Some embodiments of this application provide a battery cell 20, including a housing 22 and an electrode assembly 21. The electrode assembly 21 includes a first electrode 211, a second electrode 212, and a separator 213. The first electrode 211 and the second electrode 212 have opposite polarities and are wound together along the winding direction. The separator 213 is disposed between the first electrode 211 and the second electrode 212. The first electrode 211 includes a first winding portion 2111 and a second winding portion 2112. Both the first winding portion 2111 and the second winding portion 2112 include two oppositely arranged first straight portions 211a and two oppositely arranged first corner portions 211b. Each of the two first straight portions 211a of the first winding portion 2111 has a first tab 2113, while only one of the first straight portions 211a of the second winding portion 2112 has a first tab 2113. The second electrode 212 includes a third winding portion 2121 and a fourth winding portion 2122. Both the third winding portion 2121 and the fourth winding portion 2122 include two opposing second straight portions 212a and two opposing second corner portions 212b. Each of the two second straight portions 212a of the third winding portion 2121 has a second tab 2123, while only one of the second straight portions 212a of the fourth winding portion 2122 has a second tab 2123. In this way, the battery cell 20 can improve the conductivity of the first winding portion 2111 and the third winding portion 2121, and reduce the risk of lithium plating.

[0144] Optionally, the first winding portion 2111 is disposed in the inner ring of the second winding portion 2112, and the third winding portion 2121 is disposed in the inner ring of the fourth winding portion 2122. Optionally, in the first winding portion 2111, which is wound from the winding start end of the first electrode 211, a first tab 2113 is provided on the first straight portion 211a. In the third winding portion 2121, which is wound from the winding start end of the second electrode 212, a second tab 2123 is provided on the second straight portion 212a. This is to improve the problem of lithium plating in the inner ring.

[0145] The second aspect of this application provides a battery device 100, including a battery cell 20 as provided in the first aspect.

[0146] A third aspect of this application provides an energy storage device including a plurality of battery cells 20 as provided in the first aspect or a plurality of battery devices 100 as provided in the second aspect, wherein the battery cells 20 or battery devices 100 are used to store or provide electrical energy.

[0147] The fourth aspect of this application provides an electrical device, including a battery cell 20 of the first aspect, a battery device 100 of the second aspect, or an energy storage device of the third aspect, wherein the battery cell 20 or the battery device 100 is used to provide electrical energy to the electrical device.

[0148] The power supply device can be any of the aforementioned devices or systems that utilize battery device 100.

[0149] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: shell; An electrode assembly is housed within the housing. The electrode assembly includes a first electrode, a second electrode, and a separator. The first electrode and the second electrode have opposite polarities and are wound together along the winding direction. The separator is disposed between the first electrode and the second electrode. The first electrode includes a first winding portion and a second winding portion. Both the first winding portion and the second winding portion include two first straight portions and two first corner portions arranged opposite to each other. The first straight portions are connected to the first corner portions. The two first straight portions of the first winding portion are provided with first electrode tabs. The first straight portion of the second winding portion is provided with a first electrode tab on one of the first straight portions.

2. The battery cell as described in claim 1, characterized in that, The first winding portion is disposed on the inner ring of the second winding portion.

3. The battery cell as described in claim 2, characterized in that, The first winding portion starts winding from the starting end of the first electrode sheet, and the number of turns of the first winding portion is 1 to 3.

4. The battery cell according to any one of claims 1-3, characterized in that, Multiple first electrode tabs are stacked.

5. The battery cell as described in claim 4, characterized in that, On the first side of the first electrode sheet at the starting end of the winding, the first electrode tabs are respectively provided on a plurality of the first straight portions; On the second side of the winding start end of the first electrode sheet, at least one of the first straight portions is provided with the first electrode tab, and the first side and the second side are arranged opposite to each other along the thickness direction of the electrode assembly.

6. The battery cell according to any one of claims 1-5, characterized in that, The second electrode includes a multi-turn third winding portion, and each turn of the third winding portion includes two oppositely arranged second straight portions and two oppositely arranged second corner portions, with the second straight portions connected to the second corner portions; Each turn of the third winding portion is provided with a second electrode tab on a second straight portion; the first electrode is an anode plate, and the second electrode is a cathode plate.

7. The battery cell according to any one of claims 1-5, characterized in that, The second electrode includes a third winding portion and a fourth winding portion. Both the third winding portion and the fourth winding portion include two oppositely arranged second straight portions and two oppositely arranged second corner portions. The second straight portions are connected to the second corner portions. The two second straight portions of the third winding portion are provided with second electrode tabs, and one of the second straight portions of the fourth winding portion is provided with a second electrode tab.

8. The battery cell as described in claim 7, characterized in that, The third winding portion is disposed on the inner ring of the fourth winding portion.

9. The battery cell as described in claim 8, characterized in that, The third winding section starts winding from the starting end of the second electrode sheet, and the number of turns of the third winding section is 1 to 3.

10. The battery cell according to any one of claims 7-9, characterized in that, The first electrode tabs are provided at both ends of the two first straight portions of the first winding portion along the first direction, and the first electrode tabs are provided at both ends of one first straight portion of the second winding portion along the first direction, wherein the first direction is parallel to the width direction of the first electrode sheet. The two second straight sections in the third winding section are provided with second pole tabs at their opposite ends along the first direction, and one of the second straight sections in the fourth winding section is provided with second pole tabs at its opposite ends along the first direction.

11. The battery cell as described in claim 10, characterized in that, The housing has two end caps arranged opposite each other. One end cap is provided with a first electrode terminal and a second electrode terminal, and the other end cap is provided with a third electrode terminal and a fourth electrode terminal. The first tabs at opposite ends of the first straight portion are electrically connected to the first electrode terminal and the third electrode terminal, respectively, and the second tabs at opposite ends of the second straight portion are electrically connected to the second electrode terminal and the fourth electrode terminal, respectively.

12. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-11.

13. An energy storage device, characterized in that, It includes a plurality of battery cells as described in any one of claims 1-11 or a plurality of battery devices as described in claim 12, wherein the battery cells or the battery devices are used to store or provide electrical energy.

14. An electrical appliance, characterized in that, Includes a battery cell as described in any one of claims 1-11, a battery device as described in claim 12, or an energy storage device as described in claim 13, wherein the battery cell or the battery device is used to store or provide electrical energy.

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