Battery cell, battery, and electrical device

Abstract

A battery cell (10), a battery (100), and an electrical device. Connecting portions (42) are connected between tabs (32) and electrode terminals (11), so that during charging and discharging, current flows through the connecting portions (42) from the electrode terminals (11), and then is gradually transmitted to current collector bodies (31) from the tabs (32); or flows through the tabs (32) from the current collector bodies (31), and then is transmitted outwards from the connecting portions (42). Since the area of the minimum overcurrent cross section of the connecting portion (42) is less than the sum of the areas of the minimum overcurrent cross sections of the tabs (32) connected to the same connecting portion (42), that is, the minimum overcurrent area of the connecting portion (42) is less than the sum of the minimum overcurrent areas of the tabs (32), the overcurrent capability of the connecting portion (42) is lower than the sum of the overcurrent capabilities of the tabs (32). In this way, if an abnormal current occurs, such as an excessively high current, the part of the connecting portion (42) located between the tabs (32) and the electrode terminal (11) will fracture prior to the tabs (32), so that the current conduction between an adapter (4) and the tabs (32) is disconnected to halt the continuation of the abnormal current, and damage to an electrode assembly (3) due to the temperature rise at the tabs (32) is reduced, thereby improving the reliability of the battery cell (10).

Description

Battery cells, batteries and electrical devices Technical Field

[0001] The present application relates to the field of battery technology, and in particular to battery cells, batteries, and electrical devices. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] Battery cells are widely used in electric vehicles and consumer electronics due to their long cycle life, lack of memory effect, and minimal environmental pollution. As their applications expand, the demand for their reliability increases. Therefore, improving their reliability is a pressing technical challenge.

[0004] Summary of the Invention

[0005] Based on this, it is necessary to provide a battery cell, a battery and an electrical device to effectively improve the reliability of the battery cell.

[0006] In the first aspect, the present application provides a battery cell, which includes: a shell; at least one electrode assembly, which is accommodated in the shell, the electrode assembly includes a pole piece, the pole piece includes a current collector and an active material, the current collector includes a current collector body and a plurality of pole tabs, the current collector body is coated with active material, and the pole tabs are not coated with active material; an electrode terminal, which is arranged in the shell; a adapter, which includes at least one connecting portion, which is used to connect the pole tab and the electrode terminal; wherein the area of ​​the minimum flow cross-section of the connecting portion is S1, and the sum of the areas of the minimum flow cross-sections of the pole tabs connected to the same connecting portion is S2, and S1<S2.

[0007] The above-mentioned battery cell connects the connection part between the tab and the electrode terminal, so that during charging and discharging, the current flows from the electrode terminal through the connection part, and then gradually transmits from the tab to the current collector body; or, flows from the current collector body through the tab, and then transmits outward from the connection part. Because the area of ​​the minimum flow cross section of the connection part is smaller than the sum of the areas of the minimum flow cross sections of each tab connected to the same connection part, that is, the minimum flow area of ​​the connection part is smaller than the sum of the minimum flow areas of the tabs, the flow capacity of the connection part is lower than the sum of the flow capacities of the tabs. With this design, if the current is abnormal, such as the current is too large, the part of the connection part between the tab and the electrode terminal will break first, disconnecting the current conduction between the adapter and the tab, blocking the continuation of the current abnormality, reducing the damage to the electrode assembly due to the temperature rise at the tab position, and thus improving the reliability of the battery cell.

[0008] In some embodiments, the material of the current collector includes only metal elements, the minimum flow area of ​​a single tab is S3, the number of tabs connected to the same connection portion is N, and S2 is equal to the product of S3 and N. This design ensures that the sum of the flow capacity of the tabs connected to the same connection portion is greater than the flow capacity of the connection portion, protecting the positive electrode tab when the battery current is high and reducing damage to it, ensuring that the battery has good charge and discharge functions, thereby further improving the battery life and power performance.

[0009] In some embodiments, the current collector includes a stacked insulating support layer and conductive layers disposed on both sides of the insulating support layer. The sum of the minimum flow areas of the conductive layers disposed on both sides of the tab is S4, the number of tabs connected to the same connection portion is N, and S2 is equal to the product of S4 and N. This design ensures that the sum of the flow capacity of the tabs connected to the same connection portion is greater than the flow capacity of the connection portion, protecting the positive electrode tab and reducing damage when the battery current is high. This allows the battery with the composite current collector to have good charge and discharge capabilities, thereby further improving the battery life and power performance.

[0010] In some embodiments, the current collector further includes a transition metal foil, which is used to connect the tab and the connection portion. In this design, the introduction of the transition metal foil facilitates the connection between the tab and the connection portion, thereby improving the stability of the structure.

[0011] In some embodiments, the transition metal foil is welded to the tab to form a first weld mark, and the transition metal foil and the connection portion form a second weld mark. The minimum cross-sectional area of ​​the transition metal foil between the first and second weld marks is S5, where S5>S1. With this design, if a current anomaly occurs, such as excessive current, the connection portion between the transition metal foil and the electrode terminal will break before the tab, severing the current flow between the adapter and the tab, preventing the abnormal current flow and reducing damage to the electrode assembly due to temperature rise at the tab, thereby improving the reliability of the battery cell.

[0012] In some embodiments, the thickness of the conductive layer of the current collector is H1, 300 nm ≤ H1 ≤ 4000 nm. By controlling the thickness of the conductive layer of the current collector to between 300 nm and 4000 nm, the current collector can have good conductivity, reduce the internal resistance of the battery, and thus improve the mass energy density of the battery at the same weight.

[0013] In some embodiments, the conductive layer comprises at least one of aluminum and copper. With this design, the conductive layer material is appropriately selected to produce a battery cell with stable performance.

[0014] In some embodiments, the insulating support layer comprises a polymer material. This design makes the resulting composite current collector structure more stable and reliable.

[0015] In some embodiments, the tab is disposed at at least one end of the current collector body along a preset direction, the length of the current collector body along the preset direction is A, the thickness of the conductive layer of the current collector body is H1, wherein 10 5 ≤A / H1≤3×10 5 In this way, when designing, increasing the length of the current collector body can correspondingly increase the thickness of the conductive layer, which can effectively improve the current distribution density of the battery cell during charging and discharging, and is beneficial to improving the overall performance of the battery.

[0016] In some embodiments, the length A satisfies the condition: 150 mm ≤ A ≤ 1500 mm. With this design, the length of the coating area can be properly controlled to shorten the current flow path and transmission time on the current collector, thereby facilitating uniform distribution of current density.

[0017] In some embodiments, the electrode assemblies include at least two, each of which is stacked sequentially. The adapter includes multiple connecting portions, and the multiple tabs on each electrode assembly are connected to the connecting portions. This design, by introducing multiple electrode assemblies and stacking them sequentially, increases the number of electrode assemblies within a reasonable space and improves the capacity of the battery cells.

[0018] In some embodiments, the adapter includes a current collecting portion connected to a connecting portion, the connecting portion being connected to a tab on the electrode assembly, and the current collecting portion being connected to an electrode terminal. This design allows the adapter to break at each connecting portion when the current increases abnormally, effectively protecting the electrode assembly from damage.

[0019] In some embodiments, the housing is square in shape and includes a shell and at least one end cover. The shell has an opening at only one end, and the end cover covers the opening; or both ends of the shell have openings, and the two end covers cover the two openings respectively.

[0020] Such a design can effectively reduce the damage caused by the temperature rise at the tab position of the battery cell having one end cover or two end covers, thereby improving the reliability of the battery cell.

[0021] In some embodiments, the outer shell is a soft-pack structure, and the outer shell material includes an aluminum-plastic film. This design can effectively reduce damage to the soft-pack battery caused by temperature rise at the tab position, thereby improving the reliability of the battery cell.

[0022] In some embodiments, the outer shell is cylindrical and includes a shell and at least one end cap, which covers the opening of the shell. The outer diameter of the cylinder is greater than or equal to 30 mm. This design can effectively reduce damage to batteries with an outer diameter greater than or equal to 30 mm caused by temperature rise at the tab location, thereby improving the reliability of the battery cells.

[0023] In a second aspect, the present application provides a battery comprising any one of the battery cells described above.

[0024] In a third aspect, the present application provides an electrical device, which includes the above battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0026] FIG2 is an exploded view of a battery provided in some embodiments of the present application.

[0027] FIG3 is a schematic diagram of the exploded structure of a battery cell provided in some embodiments of the present application.

[0028] FIG4 is a schematic structural diagram of an adapter provided in some embodiments of the present application.

[0029] FIG5 is a first structural schematic diagram of an electrode assembly with a metal current collector provided in some embodiments of the present application.

[0030] FIG6 is a structural cross-sectional view of the electrode assembly in FIG5 .

[0031] FIG7 is a second structural schematic diagram of an electrode assembly with a metal current collector provided in some embodiments of the present application.

[0032] FIG8 is a first cross-sectional view of the structure of an electrode assembly with a composite current collector provided in some embodiments of the present application.

[0033] FIG9 is a second structural cross-sectional view of an electrode assembly with a composite current collector provided in some embodiments of the present application.

[0034] 1000, vehicle; 100, battery; 200, controller; 300, motor; 10, battery cell; 20, casing; 201, first part; 202, second part; 1a, outer shell; 1, end cap; 11, electrode terminal; 2, shell; 21, opening; 3, electrode assembly; 31, current collector body; 32, tab; 321, positive tab; 322, negative tab; T, protrusion extension direction; 33, current collector; 331, insulating support layer; 332, conductive layer; 34, active material; 35, transition metal foil; 36, first weld mark; 37, second weld mark; 4, adapter; 41, confluence part; 42, connection part; P, preset direction; Z, spacing direction. DETAILED DESCRIPTION

[0035] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0036] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0037] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0038] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0039] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0040] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0041] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0042] During the charge and discharge process of a battery cell, current can flow from the electrode terminals through the adapter, the tabs, and gradually into the main body of the electrode assembly. Alternatively, current can flow from the main body of the electrode assembly through the tabs and the adapter, gradually toward the electrode terminals. If current abnormalities occur during charge and discharge, such as excessive current, the tabs in traditional battery cells have poor current-carrying capacity, which can easily cause temperature rise or fracture at the tabs, damaging the battery cell and affecting its reliability.

[0043] Based on this, in order to effectively improve the reliability of battery cells, the present application provides a battery cell, in which a connecting portion is connected between the tab and the electrode terminal, so that during charging and discharging, the current flows from the electrode terminal through the connecting portion, and then gradually transmits from the tab to the current collector body; or, flows from the current collector body through the tab; and then transmits outward from the connecting portion. Since the area of ​​the minimum flow cross section of the connecting portion is smaller than the sum of the areas of the minimum flow cross sections of each tab connected to the same connecting portion, that is, the minimum flow area of ​​the connecting portion is smaller than the sum of the minimum flow areas of the tabs, the flow capacity of the connecting portion is lower than the sum of the flow capacities of the tabs. With such a design, if the current is abnormal, such as the current is too large, the portion of the connecting portion between the tab and the electrode terminal will break first, disconnecting the current conduction between the adapter and the tab, blocking the continuation of the current abnormality, and reducing the damage to the electrode assembly due to the temperature rise at the tab position, thereby improving the reliability of the battery cell.

[0044] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and batteries disclosed in this application can be used to alleviate and automatically regulate deterioration in cell expansion, replenish electrolyte consumption, and improve battery performance stability and battery life.

[0045] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0046] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0047] Please refer to Figure 1, which is a schematic structural diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an 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 power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0048] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0049] Please refer to Figure 2, which is an exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 20 and a battery cell 10, with the battery cell 10 housed within the housing 20. The housing 20 is used to provide a storage space for the battery cell 10, and the housing 20 can have various structures. In some embodiments, the housing 20 can include a first portion 201 and a second portion 202, which overlap with each other and together define a storage space for the battery cell 10. The second portion 202 can be a hollow structure with an opening 21 at one end, and the first portion 201 can be a plate-like structure, with the first portion 201 overlapping the open side of the second portion 202, so that the first portion 201 and the second portion 202 jointly define a storage space. The first portion 201 and the second portion 202 can also be hollow structures with an opening 21 on one side, with the open side of the first portion 201 overlapping the open side of the second portion 202. Of course, the box body 20 formed by the first part 201 and the second part 202 can be in various shapes, such as a cylinder, a cuboid, etc.

[0050] In the battery 100, there may be multiple battery cells 10, and the multiple battery cells 10 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 10. The multiple battery cells 10 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery 100 may be housed within the housing 20. Of course, the battery 100 may also be a battery module 100 formed by first connecting multiple battery cells 10 in series, in parallel, or in a hybrid connection, and then the multiple battery modules 100 may be connected in series, in parallel, or in a hybrid connection to form an entire battery 100, and then housed within the housing 20. The battery 100 may also include other structures. For example, the battery 100 may also include a busbar 41 for electrically connecting the multiple battery cells 10.

[0051] Each battery cell 10 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 10 can be cylindrical, flat, rectangular, or in other shapes.

[0052] Please refer to Figure 3, which is a schematic diagram of the exploded structure of a battery cell 10 provided in some embodiments of the present application. A battery cell 10 is the smallest unit that makes up a battery 100. As shown in Figure 3, a battery cell 10 includes an end cap 1, a housing 2, an electrode assembly 3, and other functional components.

[0053] The end cap 1 refers to a component that covers the opening 21 of the shell 2 to isolate the internal environment of the battery cell 10 from the external environment. Without limitation, the shape of the end cap 1 can be adapted to the shape of the shell 2 to match the shell 2. The end cap 1 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 1 is not easily deformed when squeezed or collided, so that the battery cell 10 can have a higher structural strength and improved safety performance. Functional components such as electrode terminals 11 can be provided on the end cap 1. The electrode terminal 11 can be used to electrically connect to the electrode assembly 3 for outputting or inputting electrical energy of the battery cell 10. In some embodiments, the end cap 1 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 10 reaches a threshold. The material of the end cap 1 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this. In some embodiments, an insulating member may be provided inside the end cap 1 to isolate the electrical connection portion 42 in the housing 2 from the end cap 1 to reduce the risk of short circuit. For example, the insulating member may be made of plastic, rubber, or the like.

[0054] The shell 2 is a component used to cooperate with the end cap 1 to form the internal environment of the battery cell 10, wherein the formed internal environment can be used to accommodate the electrode assembly 3, electrolyte and other components. The shell 2 and the end cap 1 can be independent components. An opening 21 can be set on the shell 2, and the internal environment of the battery cell 10 is formed by covering the opening 21 with the end cap 1 at the opening 21. Without limitation, the end cap 1 and the shell 2 can also be integrated. Specifically, the end cap 1 and the shell 2 can form a common connection surface before other components are inserted into the shell. When the interior of the shell 2 needs to be encapsulated, the end cap 1 is covered with the shell 2. The shell 2 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 2 can be determined according to the specific shape and size of the electrode assembly 3. The material of the shell 2 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this.

[0055] The electrode assembly 3 is a component in the battery cell 10 where electrochemical reactions occur. One or more electrode assemblies 3 may be contained in the shell 2. The electrode assembly 3 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly 3, and the parts of the positive and negative electrode sheets without active materials each constitute a tab 32. The positive tab 321 and the negative tab 322 may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery 100, the positive active material and the negative active material react with the electrolyte, and the tab 32 connects to the electrode terminal 11 to form a current loop.

[0056] According to some embodiments of the present application, the present application provides a battery cell 10, please refer to Figures 3 and 4, the battery cell 10 includes: a shell 1a; at least one electrode assembly 3, accommodated in the shell 1a, the electrode assembly 3 includes a pole piece, the pole piece includes a current collector 33 and an active material 34, the current collector 33 includes a current collector body 31 and multiple pole tabs 32, the current collector body 31 is coated with active material 34, and the pole tabs 32 are not coated with active material 34; an electrode terminal 11, arranged in the shell 1a; an adapter 4, including at least one connecting portion 42, the connecting portion 42 is used to connect the pole tab 32 and the electrode terminal 11; wherein the area of ​​the minimum flow cross-section of the connecting portion 42 is S1, and the sum of the areas of the minimum flow cross-sections of the pole tabs 32 connected to the same connecting portion 42 is S2, S1<S2.

[0057] The outer shell 1 a refers to the external structure of the battery cell 10 , which is used to accommodate the electrode assembly 3 and the adapter 4 , and may include a shell 2 and an end cap 1 covering an opening 21 of the shell 2 .

[0058] The current collector 33 not only provides support for the active material layer but also collects the current generated by the active material layer for external transmission. It can be a metal current collector 33, such as copper foil or aluminum foil, or a composite current collector 33. The current collector body 31 refers to the structure of the current collector 33 coated with active material 34, while the tab 32 refers to the structure of the current collector 33 not coated with active material 34. When the current collector 33 is a metal current collector 33, the tab 32 is also made solely of metal. In this case, the minimum cross-section of the tab 32 refers to the entire cross-section of the tab 32. When the current collector 33 is a composite current collector 33, the tab 32 includes an insulating support layer 331 and a conductive layer 332 disposed on the insulating support layer 331. Since the insulating support layer 331 cannot pass current, the minimum cross-section of the tab 32 is the sum of the cross-sections of the conductive layer 332 on the insulating support layer 331. This can also be understood as the entire cross-section of the tab 32 minus the cross-section of the insulating support layer 331. In some examples, a cutter is used to cut the edge of the metal current collector 33 or the composite current collector 33 , so that a plurality of tabs 32 are raised on the edge of the current collector body 31 .

[0059] The active material may include a positive electrode active material 34 and a negative electrode active material 34 , and the positive electrode active material 34 and the negative electrode active material 34 are respectively disposed on corresponding conductive layers 332 .

[0060] As an example, the positive electrode active material 34 may include at least one of the following lithium ion active materials 34: lithium phosphates containing olivine structure, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials 34 of the battery 100 may also be used. These positive electrode active materials 34 may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds. Examples of olivine-structured lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0061] The negative electrode active material 34 may be a negative electrode active material 34 for the battery 100 that is well known in the art. As a non-limiting example, the negative electrode active material 34 may include one or more of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. Silicon-based materials may include one or more of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxides, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as the negative electrode active material 34 of the battery 100 may also be used. These negative electrode active materials 34 may be used alone or in combination of two or more.

[0062] The connection portion 42 is the component that connects the tab 32 and the electrode terminal 11, enabling current conduction between the tab 32 and the electrode terminal 11. When the current is too high during cyclic charge and discharge, because the minimum cross-sectional area of ​​the connection portion 42 is smaller than the sum of the minimum cross-sectional areas of the tabs 32, the connection portion 42 is more likely to overheat and disconnect between the connection point of the electrode terminal 11 and the connection point of the tab 32, thus blocking the flow of abnormal current and effectively reducing damage to the electrode assembly 3 due to temperature rise at the tab 32.

[0063] The connection portion 42 and the tab 32 may be directly connected or indirectly connected, for example, the connection portion 42 is connected to the tab 32 through an intermediate structure. At the same time, the connection method between the tab 32 and the electrode terminal 11 on the adapter 4 may be, but is not limited to, welding.

[0064] Furthermore, the minimum cross-section of the connection portion 42 refers to the cross-section of the connection portion 42 perpendicular to the current flow direction, with the smallest cross-section area. To facilitate understanding of the minimum cross-section of the connection portion 42, refer to Figure 4 , where the minimum cross-section of the connection portion 42 is the cross-section indicated by S1 in Figure 4 . Similarly, the minimum cross-section of the tab 32 refers to the cross-section of the tab 32 perpendicular to the current flow direction, with the smallest cross-section area.

[0065] The sum of the areas of the minimum cross-sections of the tabs 32, S2, can be understood as follows: during lamination or winding, there are multiple tabs 32, and tabs 32 of the same polarity are stacked together, such as the positive tabs 321 stacked together and the negative tabs 322 stacked together. During the charge and discharge process, current flows through each tab 32 connected to the same connection portion 42. Therefore, S2 is the sum of the areas of the minimum cross-sections of each tab 32 connected to the same connection portion 42.

[0066] With such a design, if an abnormal current occurs, such as an excessively large current, the connection portion 42 located between the tab 32 and the electrode terminal 11 will break before the tab 32, disconnecting the current conduction between the adapter 4 and the tab 32, thereby blocking the continuation of the abnormal current flow and reducing damage to the electrode assembly 3 due to the temperature rise at the tab 32, thereby improving the reliability of the battery cell 10.

[0067] According to some embodiments of the present application, optionally, referring to Figures 5 and 6, the material of the current collector 33 includes only metal elements, the minimum flow area of ​​a single tab 32 is S3, the number of tabs 32 connected to the same connecting portion 42 is N, and S2 is equal to the product of S3 and N.

[0068] The material of the current collector 33 includes only metal elements, indicating that the current collector 33 is a metal current collector 33, and its material can be aluminum, copper, etc. In this case, both the current collector body 31 and the tab 32 include only metal elements. Therefore, when calculating the minimum flow cross section of the tab 32, it is only necessary to cut the tab 32 with a plane perpendicular to the direction of current flow in the tab 32. The obtained cross section with the smallest area is the minimum flow cross section of the tab 32. For reference, Figure 5 shows that the minimum flow cross section of a single tab 32 is the cross section indicated by S3 in Figure 5.

[0069] In some examples, the area S1 of the tab 32 further satisfies the condition: S1 < (L × H2 × N) / b, where L is the minimum width of the tab 32, H2 is the thickness of the tab 32, and b is a constant, 1 ≤ b ≤ 2. The location of the minimum width L of the tab 32 represents the location of the minimum current flow capacity of the tab 32. The width of the tab 32 can remain consistent along the protrusion extension direction T, i.e., the tab 32 has a uniform width, as shown in FIG5 . Alternatively, the width of the tab 32 can vary, for example, the tab 32 can become wider the closer it is to the main body 31 along the protrusion extension direction T, as shown in FIG6 .

[0070] Among them, b is a constant, which is obtained through experience. Its main function is to ensure that the overcurrent requirements of the tab 32 can be met throughout its entire life cycle, because the tab 32 will be degraded during use, and the overcurrent and conductivity will be attenuated to a certain extent. Among them, b≥1 is mainly to protect the overcurrent capacity of the tab 32, which can reduce the probability of damage to the tab 32. However, b≤2 limits the value of b to be too large, resulting in the overcurrent capacity of the adapter 4 being too small, affecting the overall conductivity of the battery cell 10. In the design of the battery 100, the area S1 of the minimum overcurrent cross-section of the connecting portion 42 is set to the minimum overcurrent area of ​​the battery cell 10, so that when the current of the battery 100 is large, the adapter 4 is first blown, thereby protecting the tab 32.

[0071] For ease of understanding, assume that the total number of positive electrode tabs 321 in a battery cell 10 (or electrode assembly 3) is 40, the thickness H2 of the positive electrode tab 321 connected to the same adapter 4 is 1 micron (μm), and the minimum width of the positive electrode tab 321 is 100 mm. In this case, the minimum cross-sectional area S1 is less than 4 mm. 2 / b. When b is 1, the minimum cross-sectional area S1 is less than 4 mm 2 .

[0072] Among them, H1 includes but is not limited to: 500nm, 1000nm, 1500nm, 2000nm, 2500nm, 3000nm, 3500nm, 4000nm; b includes but is not limited to: 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.

[0073] Such a design ensures that the sum of the overcurrent capacity of the tabs 32 connected to the same connection part 42 is greater than the overcurrent capacity of the connection part 42, thereby protecting the positive electrode tab 321 when the current of the battery 100 is large, reducing its damage, and enabling the battery 100 to have good charge and discharge functions, thereby further improving the life and power performance of the battery 100.

[0074] According to some embodiments of the present application, optionally, referring to Figures 8 and 9, the current collector 33 includes a stacked insulating support layer 331 and a conductive layer 332 arranged on both sides of the insulating support layer 331, the sum of the minimum flow areas of the conductive layers 332 arranged on both sides of the tabs 32 is S4, the number of tabs 32 connected to the same connecting portion 42 is N, and S2 is equal to the product of S4 and N.

[0075] The insulating support layer 331 is a structure that supports the current collector 33. Its material can be selected from at least one of an organic polymer insulating material, an inorganic insulating material, and a composite material. The organic polymer insulating material is preferably at least one of polyamide, polyterephthalate, polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer, polybutylene terephthalate, poly(p-phenylene terephthalamide), polypropylene, polyoxymethylene, epoxy resin, phenolic resin, polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, and polycarbonate. The inorganic insulating material is preferably at least one of aluminum oxide, silicon carbide, and silicon dioxide. The composite material is preferably at least one of epoxy resin glass fiber reinforced composite material and polyester resin glass fiber reinforced composite material.

[0076] The conductive layer 332 is a structure with a conductive function that can collect the current generated by the active material layer for external output. At the same time, in the electrode, the side of the conductive layer 332 of the current collector body 31 facing away from the insulating support layer 331 is used to coat the active material 34, such as lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium iron phosphate, ternary materials, etc., and can also be coated with graphite, silicon oxide, etc. When one side of the conductive layer 332 is coated with materials such as lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium iron phosphate, ternary materials, etc., the resulting electrode is a positive electrode; when one side of the conductive layer 332 is coated with materials such as graphite, silicon oxide, etc., the resulting electrode is a negative electrode.

[0077] The conductive layer 332 may be copper foil, aluminum foil, etc. The thickness of the conductive layer 332 of the current collector body 31 may be the same as or different from the thickness of the tab 32 .

[0078] When the current collector 33 is a composite current collector 33, since the insulating support layer 331 is an insulating material and cannot pass current, the minimum flow cross-section on the tab 32 should be the sum of the minimum flow cross-sections on the conductive layers 332 on both sides of the insulating support layer 331, wherein the current collector body 31 and the tab 32 both include an insulating support layer 331 and a conductive layer 332 arranged on both sides of the insulating support layer 331.

[0079] Similarly, in some examples, the area S1 of the tab 32 further satisfies the condition: S1 < (L × H2 × N) / b; where L is the minimum width of the tab 32, and H2 is the sum of the thicknesses of the conductive layer 332 on both sides of the tab 32, which is equal to H0 minus H3 in FIG9 . b is a constant, 1 ≤ b ≤ 2. The location of the minimum width L of the tab 32 represents the location of the minimum current carrying capacity of the tab 32. The width of the tab 32 can remain consistent along the protrusion extension direction T, that is, the tab 32 has a uniform width. For details, see FIG8 . Furthermore, in some other embodiments, b further satisfies the condition: 1.333 ≤ b ≤ 1.67. For example, it can be, but is not limited to, 1.333, 1.4, 1.42, 1.44, 1.46, 1.48, 1.5, 1.55, 1.6, 1.62, 1.64, 1.67, etc.

[0080] Such a design ensures that the sum of the current-carrying capacity of the tabs 32 connected to the same connecting portion 42 is greater than the current-carrying capacity of the connecting portion 42, thereby protecting the positive electrode tab 321 when the current of the battery 100 is large and reducing damage thereto, so that the battery 100 with the composite current collector 33 has good charge and discharge functions, thereby further improving the life and power performance of the battery 100.

[0081] According to some embodiments of the present application, optionally, referring to FIG. 8 and FIG. 9 , the current collector 33 further includes a transition metal foil 35 , and the transition metal foil 35 is used to connect the electrode tab 32 and the connecting portion 42 .

[0082] The transition metal foil 35 is a structure connected between the tab 32 and the connecting portion 42 to achieve indirect connection between the tab 32 and the connecting portion 42. For example, the connecting portion 42 is welded to the tab 32 through the transition metal foil 35. The transition metal foil 35 can be made of, but is not limited to, aluminum, copper, or the like.

[0083] With such a design, the transition metal foil 35 is introduced to facilitate the connection between the tab 32 and the connecting portion 42 , thereby improving the stability of the structure.

[0084] According to some embodiments of the present application, optionally, referring to Figures 4, 8 and 9, the transition metal foil 35 is welded to the tab 32 to form a first weld mark 36, the transition metal foil 35 and the connecting portion 42 form a second weld mark 37, and the area of ​​the minimum flow cross-section of the portion of the transition metal foil 35 between the first weld mark 36 and the second weld mark 37 is S5, and S5>S1.

[0085] The first weld mark 36 is formed by welding the transition metal foil 35 to the tab 32, forming a welded structure between them. The second weld mark 37 is formed by welding the transition metal foil 35 to the connection portion 42, forming a welded structure between them. During the charge and discharge process, current flows between the first weld mark 36 and the second weld mark 37. To this end, the minimum cross-sectional area of ​​the transition metal foil 35 is larger than the minimum cross-sectional area of ​​the connection portion 42. This places the current bottleneck of the battery cell 10 at the connection portion 42, making it more likely to cause a fuse at the connection portion 42 in the event of a current anomaly.

[0086] The minimum flow cross section of the transition metal foil 35 refers to the cross section with the smallest area in the cross section of the transition metal foil 35 perpendicular to the current flow direction in the current flow direction of the transition metal foil 35 .

[0087] In some examples, the minimum flow area S5 of the transition metal foil 35, the minimum flow area S1 of the connection portion 42, and the sum of the minimum flow areas of the tab 32 connected to the same connection portion 42 satisfy the condition: S5>S2>S1. This means that the connection portion 42 has the weakest flow capacity among the three and is most likely to fuse.

[0088] With such a design, if an abnormal current occurs, such as an excessively large current, the connection portion 42 located between the adapter metal foil 35 and the electrode terminal 11 will break before the tab 32, disconnecting the current conduction between the adapter 4 and the tab 32, thereby blocking the continuation of the abnormal current flow and reducing damage to the electrode assembly 3 due to the temperature rise at the tab 32, thereby improving the reliability of the battery cell 10.

[0089] According to some embodiments of the present application, optionally, referring to FIG. 9 , the thickness of the conductive layer 332 of the current collector body 31 is H1, 300 nm ≤ H1 ≤ 4000 nm.

[0090] The thickness of the conductive layer 332 in the current collector 33 is 300 nm to 4000 nm. For example, it can be, but is not limited to, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1500 nm, 1800 nm, 2000 nm, 2200 nm, 2500 nm, 3000 nm, 3500 nm, or 4000 nm. Of course, in other embodiments, the thickness of the conductive layer 332 can also be 800 nm to 2000 nm. For example, it can be, but is not limited to, 800 nm, 850 nm, 900 nm, 950 nm, 1000 nm, 1200 nm, 1400 nm, 1600 nm, 1800 nm, or 2000 nm.

[0091] The thickness of a conventional pure metal layer current collector 33 is generally around 10 microns. For example, a conventional positive electrode current collector 33 generally uses a 13-micron thick pure aluminum foil. However, in the present application, the thickness of the conductive layer 332 in the composite current collector 33 is controlled within the above range, which can ensure that the current collector 33 has good conductivity, reduce the internal resistance of the battery 100, and thus improve the mass energy density of the battery 100 while maintaining the same weight.

[0092] In addition, the thickness of the conductive layer 332 of the tab 32 is also controlled to be between 300 nm and 4000 nm.

[0093] With this design, the thickness of the conductive layer 332 of the current collector body 31 is controlled between 300 nm and 4000 nm, which can make the current collector 33 have good conductivity, reduce the internal resistance of the battery 100, and thus improve the mass energy density of the battery 100 on the basis of the same weight.

[0094] According to some embodiments of the present application, optionally, the material of the conductive layer 332 includes at least one of an aluminum metal material and a copper metal material.

[0095] The conductive layer 332 may be made of different materials according to different polarities. For example, in the positive electrode current collector 33 , the conductive layer 332 may be made of aluminum metal; in the negative electrode current collector 33 , the conductive layer 332 may be made of copper metal.

[0096] The aluminum metal material may be, but is not limited to, single-element aluminum, aluminum alloy, or a laminate of single-element aluminum and aluminum alloy. The copper metal material may be, but is not limited to, single-element copper, copper alloy, or a laminate of single-element copper and copper alloy.

[0097] With this design, the material of the conductive layer 332 is reasonably selected, and a battery cell 10 with stable performance is designed.

[0098] According to some embodiments of the present application, optionally, the material of the insulating support layer 331 includes a polymer material.

[0099] The polymer materials include, but are not limited to, polyamide, polyimide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polypropylene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyformaldehyde, polyphenylene ether, polyphenylene sulfide, polyethylene glycol, polysulfur nitride polymer materials, polyphenylene, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, phenolic resin, their derivatives, their cross-linked products and their copolymers, one or more thereof.

[0100] In addition, the material of the insulating support layer 331 includes not only polymer materials but also additives, thereby forming a polymer-based composite material. Accordingly, the insulating support layer 331 is a polymer-based composite material layer. The additives may include one or more of metal materials and inorganic non-metallic materials. Optionally, the metal material includes one or more of aluminum, nickel, iron, silver, titanium, and alloys thereof. Optionally, the inorganic non-metallic material includes one or more of graphite, conductive carbon, aluminum oxide, silicon oxide, silicon carbide, and silicon dioxide.

[0101] Such a design makes the structure of the composite current collector 33 more stable and reliable.

[0102] According to some embodiments of the present application, optionally, referring to FIG8 and FIG9, the tab 32 is provided at at least one end of the current collector body 31 along the preset direction P, the length of the current collector body 31 along the preset direction P is A, and the thickness of the conductive layer 332 of the current collector body 31 is H1, wherein 10 5 ≤A / H1≤3×10 5 .

[0103] The length of the current collector body 31 along the preset direction P can affect the current distribution density on the current collector 33. For example, the longer the current collector body 31 along the preset direction P, the longer the current transmission path on the current collector 33, the longer the transmission time, and the uneven distribution density. To this end, a positive correlation is established between the length A of the current collector body 31 and the thickness H1 of the conductive layer 332. For example, during structural design, the thickness of the conductive layer 332 is increased for current collectors 33 with longer current collector bodies 31 along the preset direction P; the thickness of the conductive layer 332 is decreased for current collectors 33 with shorter current collector bodies 31 along the preset direction P.

[0104] Among them, A / H1 can be 5 ~3×10 5 For example, A / H1 can be but not limited to 10 5 , 1.2×10 5 , 1.5×10 5 , 1.8×10 5 , 2×10 5 , 2.2×10 5 , 2.5×10 5 , 2.8×10 5 , 3×10 5 wait.

[0105] In this way, during design, increasing the length of the current collector body 31 can correspondingly increase the thickness of the conductive layer 332 , which can effectively improve the current distribution density of the battery cell 10 during charging and discharging, and is beneficial to improving the overall performance of the battery 100 .

[0106] According to some embodiments of the present application, optionally, the length A satisfies the condition: 150 mm ≤ A ≤ 1500 mm.

[0107] The length A of the current collector body 31 in the preset direction P can be between 150 mm and 1500 mm. For example, the length A can be 150 mm, 200 mm, 300 mm, 400 mm, 600 mm, 800 mm, 1000 mm, 1200 mm, 1500 mm, etc.

[0108] Furthermore, the thickness of the conductive layer 332 can affect the performance of the battery 100. For example, if the thickness of the conductive layer 332 is too large, the energy density will be reduced. If the thickness of the conductive layer 332 is too small, the production process window will be narrow, which may easily damage the substrate during production. Furthermore, if the thickness of the conductive layer 332 is too small, the tensile strength and compressive deformation resistance of the conductive layer 332 will be reduced. Therefore, the thickness H1 can be between 300nm and 4000nm. For example, the thickness H1 can be, but is not limited to, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, 2000nm, 3000nm, 4000nm, etc.

[0109] With such a design, the length of the coating area can be reasonably controlled, which can shorten the current flow path and transmission time on the current collector 33 and facilitate the control of uniform distribution of current density.

[0110] According to some embodiments of the present application, optionally, referring to FIG. 3 , the electrode assembly 3 includes at least two, each electrode assembly 3 is stacked in sequence, the adapter 4 includes multiple connecting parts 42 , and the multiple tabs 32 on each electrode assembly 3 are respectively connected to the connecting parts 42 .

[0111] The electrode assemblies 3 are stacked sequentially, increasing the capacitance without excessively increasing the overall volume of the battery cell 10. It is readily understood that the tabs 32 may include a positive tab 321 and a negative tab 322. Therefore, when the battery cell 10 is assembled, the positive tab 321 on each electrode assembly 3 is connected to one adapter 4, and the negative tab 322 on each electrode assembly 3 is connected to the other adapter 4.

[0112] Among them, when the electrode assembly 3 is a flat structure, each electrode assembly 3 can be overlapped in sequence in the thickness direction; when the electrode assembly 3 is a cylindrical structure, each electrode assembly 3 can be distributed with its cylindrical side surfaces overlapped with each other.

[0113] With this design, multiple electrode assemblies 3 are introduced and stacked in sequence, so that the number of electrode assemblies 3 is increased within a reasonable space, thereby improving the capacity of the battery cell 10.

[0114] According to some embodiments of the present application, optionally, referring to FIG. 4 , the adapter 4 includes a busbar 41 connected to a connecting portion 42 , the connecting portion 42 is connected to the tab 32 on the electrode assembly 3 , and the busbar 41 is connected to the electrode terminal 11 .

[0115] The conduit 41 is the component on the adapter 4 that connects to the electrode terminal 11. During the charge and discharge process, the current on each tab 32 converges on the conduit 41 through the corresponding connection 42, and then flows uniformly from the conduit 41 to the electrode terminal 11. Alternatively, the current on the electrode terminal 11 is diverted from the conduit 41 to the connection 42, and then flows from the connection 42 to the tab 32.

[0116] Because the connecting portions 42 are spaced apart on the confluence portion 41, the flow bottlenecks of the adapter 4 are distributed on the connecting portions 42. In some examples, in the spacing direction Z between the connecting portions 42, the connecting portions 42 at both ends do not extend beyond the ends of the confluence portion 41 along the spacing direction Z. That is, the spacing between the two opposite sides of the connecting portions 42 at both ends is less than or equal to the spacing between the two ends of the confluence portion 41 along the spacing direction Z.

[0117] Meanwhile, the number of connecting portions 42 is not limited to the two shown in FIG4 , and may be other numbers, such as three, four, five, or more. In the same adapter 4 , the relationship between the number of connecting portions 42 and the number of electrode assemblies 3 may be one-to-one or one-to-many, i.e., one connecting portion 42 may be connected to the tabs 32 of multiple electrode assemblies 3 at the same time.

[0118] In addition, the connection parts 42 and the confluence part 41 may be an integrated structure or a combined structure, for example, each connection part 42 is welded to the confluence part 41 .

[0119] With such a design, when the current increases abnormally, the adapter 4 can break at each connection portion 42 , effectively protecting the electrode assembly 3 from damage.

[0120] According to some embodiments of the present application, optionally, the shape of the shell 1a is square, and the shell 1a includes a shell body 2 and at least one end cover 1, the shell body 2 has an opening 21 at only one end, and the end cover 1 covers the opening 21; or both ends of the shell body 2 have openings 21, and the two end covers 1 cover the two openings 21 respectively.

[0121] It can be seen that the square battery cell 10 can have one end cover 1, that is, the shell 2 has an opening 21; it can also have two end covers 1, which are respectively covered on the openings 21 at opposite ends of the shell 2.

[0122] The end cap 1 is a component that fits over the opening 21 of the housing 2 to isolate the internal environment of the battery cell 10 from the external environment. The shape of the end cap 1 can be adapted to the shape of the housing 2 to fit the housing 2. The housing 2 is a component that cooperates with the end cap 1 to form an internal environment for the battery cell 10. This internal environment can be used to accommodate the electrode assembly 3, electrolyte, and other components.

[0123] Such a design can effectively reduce the damage caused by the temperature rise at the position of the tab 32 of the battery cell 10 having one end cover 1 or two end covers 1 , thereby improving the reliability of the battery cell 10 .

[0124] According to some embodiments of the present application, optionally, the shell 1a is a soft package structure, and the material of the shell 1a includes aluminum-plastic film.

[0125] It can be seen that the battery 100 in this embodiment is a soft-pack battery, and the thermal management component 31 is located in the shell 1a of the soft-pack structure and is opposite to the shell 1a, for example, in contact with the shell 1a.

[0126] Such a design can effectively reduce the damage to the soft-pack battery caused by the temperature rise at the tab 32 , thereby improving the reliability of the battery cell 10 .

[0127] According to some embodiments of the present application, optionally, the outer shell 1a is shaped like a cylinder, and the outer shell 1a includes a shell 2 and at least one end cover 1, the end cover 1 covers the opening 21 of the shell 2, and the outer diameter of the cylinder is greater than or equal to 30 mm.

[0128] The outer diameter of the cylinder can be designed to be greater than or equal to 30 mm, for example, the outer diameter can be but not limited to 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, etc.

[0129] Such a design can effectively reduce the damage caused by the temperature rise at the tab 32 of the battery with an outer diameter greater than or equal to 30 mm, thereby improving the reliability of the battery cell 10.

[0130] According to some embodiments of the present application, the present application provides a battery 100 , which includes any one of the above battery cells 10 .

[0131] According to some embodiments of the present application, optionally, the present application provides an electrical device, which includes the above battery 100.

[0132] According to some embodiments of the present application, referring to Figures 1 to 4, and Figures 8 and 9, the present application provides a battery cell 10, which includes an electrode assembly 3, an electrode terminal 11, and an adapter 4. The electrode assembly 3 includes a pole piece, and the current collector 33 of the pole piece includes a current collector body 31 and multiple positive electrode tabs 321. The adapter 4 includes a connecting portion 42 connected between the positive electrode tab 321 and the electrode terminal 11. The minimum cross-sectional area of ​​the connecting portion 42 is S1, the minimum width of the positive electrode tab 321 is L, the sum of the thicknesses of the conductive layer 332 on the positive electrode tab 321 is H2, and N is the total number of positive electrode tabs 321 connected to the same adapter 4. Wherein, S1 < (L×H2×N) / b; wherein b is a constant, 1≤b≤2.

[0133] The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0134] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A battery cell, comprising: Housing (1a); At least one electrode assembly (3) is accommodated in the housing (1a), the electrode assembly (3) comprising a pole piece, the pole piece comprising a current collector (33) and an active material (34), the current collector (33) comprising a current collector body (31) and a plurality of pole tabs (32), the current collector body (31) being coated with the active material (34), and the pole tabs (32) not being coated with the active material (34); an electrode terminal (11), disposed on the housing (1a); The adapter (4) includes at least one connecting portion (42), wherein the connecting portion (42) is used to connect the tab (32) and the electrode terminal (11); The minimum cross-sectional area of ​​the connecting portion (42) is S1, and the sum of the minimum cross-sectional areas of the tabs (32) connected to the same connecting portion (42) is S2, where S1<S2.

2. The battery cell according to claim 1, wherein: The material of the current collector (33) only includes metal elements, the minimum flow area of ​​a single pole lug (32) is S3, the number of pole lugs (32) connected to the same connecting portion (42) is N, and S2 is equal to the product of S3 and N.

3. The battery cell according to claim 1, wherein: The current collector (33) includes a stacked insulating support layer (331) and a conductive layer (332) arranged on both sides of the insulating support layer (331), the sum of the minimum flow areas of the conductive layers (332) arranged on both sides of the pole lug (32) is S4, the number of the pole lugs (32) connected to the same connecting portion (42) is N, and S2 is equal to the product of S4 and N.

4. The battery cell according to claim 3, wherein: The current collector (33) further includes a transition metal foil (35), and the transition metal foil (35) is used to connect the electrode tab (32) and the connecting portion (42).

5. The battery cell according to claim 4, wherein: The transition metal foil (35) is welded to the tab (32) to form a first weld mark (36), the transition metal foil (35) and the connecting portion (42) form a second weld mark (37), and the minimum flow cross-section area of ​​the portion of the transition metal foil (35) between the first weld mark (36) and the second weld mark (37) is S5, and S5>S1.

6. The battery cell according to any one of claims 3 to 5, wherein: The conductive layer (332) of the current collector body (31) has a thickness H1, 300nm≤H1≤4000nm.

7. The battery cell according to any one of claims 3 to 6, wherein: The material of the conductive layer (332) includes at least one of aluminum metal material and copper metal material.

8. The battery cell according to any one of claims 3 to 7, wherein: The material of the insulating support layer (331) includes a polymer material.

9. The battery cell according to any one of claims 3 to 8, wherein: The tab (32) is provided at at least one end of the current collector body (31) along a preset direction (P), the length of the current collector body (31) along the preset direction (P) is A, the thickness of the conductive layer (332) of the current collector body (31) is H1, wherein 10 5 ≤A / H1≤3×10 5 .

10. The battery cell according to claim 9, wherein: The length A satisfies the following conditions: 150mm≤A≤1500mm.

11. The battery cell according to any one of claims 1 to 10, wherein: The electrode assemblies (3) include at least two, each of the electrode assemblies (3) is stacked in sequence, the adapter (4) includes a plurality of connecting portions (42), and the plurality of tabs (32) on each of the electrode assemblies (3) are respectively connected to the connecting portions (42).

12. The battery cell according to claim 11, wherein: The adapter (4) includes a confluence portion (41) connected to the connection portion (42), the connection portion (42) is connected to the tab (32) on the electrode assembly (3), and the confluence portion (41) is connected to the electrode terminal (11).

13. The battery cell according to any one of claims 1 to 12, wherein: The housing (1a) is square in shape, comprising a shell (2) and at least one end cover (1), the shell (2) having an opening (21) at only one end, and the end cover (1) covering the opening (21); or Both ends of the shell (2) have openings (21), and the two end covers (1) cover the two openings (21) respectively.

14. The battery cell according to any one of claims 1 to 12, wherein: The shell (1a) is a soft-pack structure, and the material of the shell (1a) includes an aluminum-plastic film.

15. The battery cell according to any one of claims 1 to 12, wherein: The outer shell (1a) is in the shape of a cylinder and comprises a shell (2) and at least one end cover (1). The end cover (1) covers an opening (21) of the shell (2). The outer diameter of the cylinder is greater than or equal to 30 mm. 16 . A battery comprising the battery cell according to claim 1 .

17. An electrical device comprising the battery according to claim 16.

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