Battery monomer, battery and electric device

Abstract

According to the battery monomer, the battery and the power utilization device, the connecting part is connected between the tab and the electrode terminal, so that during charging and discharging, current flows through the connecting part from the electrode terminal and then is gradually transmitted to the current collector main body from the tab; or the current flows through the tab from the current collector main body; and then the signals are transmitted outwards through the connecting part. As the area of the minimum overflowing section of each connecting part is smaller than the sum of the areas of the minimum overflowing sections of the tabs connected with the same connecting part, namely, the minimum overflowing area of each connecting part is smaller than the sum of the minimum overflowing areas of the tabs, the overflowing capacity of each connecting part is lower than the sum of the overflowing capacity of the tabs. According to the design, when the current is abnormal, for example, the current is too large, the part of the connecting part between the tab and the electrode terminal preferentially breaks the tab, disconnects the current conduction between the adapter and the tab, blocks the continuation of the abnormal current, reduces the damage to the electrode assembly caused by the temperature rise at the position of the tab, and improves the reliability of the single battery.

Description

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 current products due to their advantages such as long cycle life, no memory effect and low environmental pollution. As the application range of battery cells becomes wider and wider, the requirements for the reliability of battery cells are getting higher and higher. Therefore, how to improve the reliability of battery cells is a technical problem that needs to be solved urgently. Utility Model Content

[0004] 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.

[0005] In the first aspect, the present application provides a battery cell, which includes: a shell; at least one electrode assembly accommodated in the shell, the electrode assembly including a pole piece, the pole piece including a current collector and an active material, the current collector including a current collector body and a plurality of pole ears, the current collector body is coated with the active material, and the pole ears are not coated with the active material; an electrode terminal, arranged in the shell; a adapter, including at least one connecting portion, the connecting portion is used to connect the pole ear 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 ears connected to the same connecting portion is S2, and S1<S2.

[0006] The above-mentioned battery cell connects the connection part between the pole lug 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 pole lug to the current collector body; or, flows from the current collector body through the pole lug; and then transmits outward from the connection part. Since 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 pole lug 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 pole lugs, the flow capacity of the connection part is lower than the sum of the flow capacities of the pole lugs. With such a design, if the current is abnormal, such as the current is too large, the part of the connection part between the pole lug and the electrode terminal will break first before the pole lug, disconnecting the current conduction between the adapter and the pole lug, blocking the continuation of the abnormal current, and reducing the damage to the electrode assembly due to the temperature rise at the pole lug position, thereby improving the reliability of the battery cell.

[0007] 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. With such a design, 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, and the positive tab is protected when the current of the battery is large, reducing its damage, so that the battery has good charge and discharge functions, thereby further improving the battery life and power performance.

[0008] In some embodiments, the current collector includes an insulating support layer and a conductive layer 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 tabs 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. In this design, 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, and the positive tab is protected when the current of the battery is large, reducing its damage, so that the battery with the composite current collector has good charge and discharge functions, thereby further improving the battery life and power performance.

[0009] In some embodiments, the current collector further includes a transition metal foil, which is used to connect the pole ear and the connecting portion. In this design, the transition metal foil is introduced to facilitate the connection between the pole ear and the connecting portion, thereby improving the stability of the structure.

[0010] In some embodiments, the transition metal foil is welded to the pole tab to form a first weld mark, the transition metal foil and the connection portion form a second weld mark, and the area of ​​the minimum current cross section of the portion of the transition metal foil between the first weld mark and the second weld mark is S5, S5>S1. With such a design, if the current is abnormal, such as the current is too large, the portion of the connection portion between the transition metal foil and the electrode terminal will break first before the pole tab, disconnecting the current conduction between the adapter and the pole tab, blocking the continuation of the abnormal current, reducing the damage to the electrode assembly due to the temperature rise at the pole tab position, and thus improving the reliability of the battery cell.

[0011] In some embodiments, the thickness of the conductive layer of the current collector is H1, 300nm≤H1≤4000nm. In this design, the thickness of the conductive layer of the current collector is controlled between 300nm and 4000nm, which can make the current collector have good conductivity, reduce the internal resistance of the battery, and thus improve the mass energy density of the battery on the basis of the same weight.

[0012] In some embodiments, the material of the conductive layer includes at least one of aluminum metal material and copper metal material. With such a design, the material of the conductive layer is reasonably selected to design a battery cell with stable performance.

[0013] In some embodiments, the material of the insulating support layer includes a polymer material. Such a design makes the formed composite current collector structure more stable and reliable.

[0014] 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 correspond to increasing 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.

[0015] In some embodiments, the length A satisfies the condition: 150 mm ≤ A ≤ 1500 mm. 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 and facilitate the control of uniform distribution of current density.

[0016] In some embodiments, the electrode assembly includes at least two, each electrode assembly is stacked in sequence, the adapter includes multiple connecting parts, and multiple tabs on each electrode assembly are respectively connected to the connecting parts. In this design, multiple electrode assemblies are introduced and stacked in sequence, so that the number of electrode assemblies is increased within a reasonable space, thereby improving the capacity of the battery cell.

[0017] In some embodiments, the adapter includes a current collecting portion connected to the connecting portion, the connecting portion is connected to the pole ear on the electrode assembly, and the current collecting portion is connected to the electrode terminal. With such a design, when the current increases abnormally, the adapter can break at each connecting portion, effectively protecting the electrode assembly from damage.

[0018] In some embodiments, the outer shell 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.

[0019] 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.

[0020] In some embodiments, the outer shell is a soft-pack structure, and the material of the outer shell includes an aluminum-plastic film. Such a design can effectively reduce the damage of the soft-pack battery caused by the temperature rise at the tab position, thereby improving the reliability of the battery cell.

[0021] In some embodiments, the outer shell is in the shape of a cylinder, and includes a shell and at least one end cover, the end cover covers the opening of the shell, and the outer diameter of the cylinder is greater than or equal to 30 mm. Such a design can effectively reduce the damage caused by the temperature rise at the tab position of the battery with an outer diameter greater than or equal to 30 mm, thereby improving the reliability of the battery cell.

[0022] In a second aspect, the present application provides a battery, the battery comprising any of the above battery cells.

[0023] In a third aspect, the present application provides an electrical device, which includes the above battery.

[0024] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0026] Figure 1 A schematic diagram of the structure of a vehicle provided for some embodiments of the present application.

[0027] Figure 2 An exploded view of a battery provided for some embodiments of the present application.

[0028] Figure 3 A schematic diagram of the exploded structure of a battery cell provided in some embodiments of the present application.

[0029] Figure 4 A schematic diagram of the structure of an adapter provided in some embodiments of the present application.

[0030] Figure 5 Schematic diagram of the structure of an electrode assembly with a metal current collector provided in some embodiments of the present application Figure 1 .

[0031] Figure 6 for Figure 5 Structural cross-sectional view of the electrode assembly.

[0032] Figure 7 Schematic diagram of the structure of an electrode assembly with a metal current collector provided in some embodiments of the present application Figure 2 .

[0033] Figure 8 Structural cross-section of an electrode assembly with a composite current collector provided in some embodiments of the present application Figure 1 .

[0034] Fig. 9 Structural cross-section of an electrode assembly with a composite current collector provided in some embodiments of the present application Figure 2 .

[0035] 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, pole ear; 321, positive pole ear; 322, negative pole ear; 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, conduit; 42, connecting part; P, preset direction; Z, spacing direction. DETAILED DESCRIPTION

[0036] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0038] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0039] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0040] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0041] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0042] In the description of the embodiments of the present application, the technical 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. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0043] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0044] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0045] During the charge and discharge process of a battery cell, the current can be transmitted from the electrode terminal through the adapter and the tab in sequence, and gradually to the main body of the electrode assembly; or it can be transmitted from the main body of the electrode assembly through the tab and the adapter in sequence, and gradually to the electrode terminal. If the current is abnormal during the charge and discharge process, such as the current is too large, the tab in the traditional battery cell has a poor current carrying capacity, and it is easy to cause temperature rise or breakage at the tab position, causing damage to the battery cell and affecting the reliability of the battery cell.

[0046] Based on this, in order to effectively improve the reliability of battery cells, the present application provides a battery cell, in which a connection part is connected between the pole ear 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 pole ear to the current collector body; or, flows from the current collector body through the pole ear; and then transmits outward from the connection part. Since 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 pole ear 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 pole ears, the flow capacity of the connection part is lower than the sum of the flow capacities of the pole ears. With such a design, if the current is abnormal, such as the current is too large, the part of the connection part between the pole ear and the electrode terminal will break first before the pole ear, disconnecting the current conduction between the adapter and the pole ear, blocking the continuation of the abnormal current, and reducing the damage to the electrode assembly due to the temperature rise at the pole ear position, thereby improving the reliability of the battery cell.

[0047] The battery cells disclosed in the embodiments of the present application can be used, but not limited to, in electrical devices such as vehicles, ships or aircraft. A power supply system comprising the battery cells and batteries disclosed in the present application can be used to form the electrical device, which is conducive to alleviating and automatically adjusting the deterioration of the expansion force of the battery cell, replenishing the consumption of the electrolyte, and improving the stability of the battery performance and the battery life.

[0048] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, 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., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0049] 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.

[0050] Please refer to Figure 1 , Figure 1A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may 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 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and 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.

[0051] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve 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.

[0052] Please refer to Figure 2 , Figure 2 An exploded view of a battery 100 provided for some embodiments of the present application. The battery 100 includes a housing 20 and a battery cell 10, and the battery cell 10 is contained in the housing 20. The housing 20 is used to provide a storage space for the battery cell 10, and the housing 20 can adopt a variety of structures. In some embodiments, the housing 20 may include a first part 201 and a second part 202, and the first part 201 and the second part 202 cover each other, and the first part 201 and the second part 202 jointly define a storage space for accommodating the battery cell 10. The second part 202 may be a hollow structure with an opening 21 at one end, and the first part 201 may be a plate-like structure, and the first part 201 covers the open side of the second part 202, so that the first part 201 and the second part 202 jointly define a storage space; the first part 201 and the second part 202 may also be hollow structures with an opening 21 on one side, and the open side of the first part 201 covers the open side of the second part 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.

[0053] In the battery 100, there can be multiple battery cells 10, and the multiple battery cells 10 can be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 10 are both connected in series and in parallel. Multiple battery cells 10 can be directly connected in series, in parallel, or in mixed connection, and then the whole formed by the multiple battery cells 10 is accommodated in the box 20; of course, the battery 100 can also be a battery 100 module in the form of multiple battery cells 10 connected in series, in parallel, or in mixed connection, and multiple battery 100 modules are then connected in series, in parallel, or in mixed connection to form a whole, and accommodated in the box 20. The battery 100 may also include other structures, for example, the battery 100 may also include a confluence 41 for realizing electrical connection between multiple battery cells 10.

[0054] Each battery cell 10 may be a secondary battery or a primary battery, or a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 10 may be cylindrical, flat, rectangular, or in other shapes.

[0055] Please refer to Figure 3 , Figure 3 The schematic diagram of the exploded structure of the battery cell 10 provided in some embodiments of the present application. The battery cell 10 refers to the smallest unit constituting the battery 100. Figure 3 The battery cell 10 includes an end cover 1, a shell 2, an electrode assembly 3 and other functional components.

[0056] 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 and collided, so that the battery cell 10 can have a higher structural strength and the safety performance can also be improved. 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 the 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 a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose special restrictions on this. In some embodiments, an insulating member may be provided inside the end cap 1, and the insulating member may be used to isolate the electrical connection part 42 in the housing 2 from the end cap 1 to reduce the risk of short circuit. For example, the insulating member may be plastic, rubber, or the like.

[0057] 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, the electrolyte and other components. The shell 2 and the end cap 1 can be independent components, and an opening 21 can be set on the shell 2, and the internal environment of the battery cell 10 is formed by covering 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 put into the shell, and 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 embodiment of the present application does not impose any special restrictions on this.

[0058] The electrode assembly 3 is a component in the battery cell 10 where electrochemical reactions occur. One or more electrode assemblies 3 may be included in the housing 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 at both ends of the main body respectively. 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 the electrode terminal 11 to form a current loop.

[0059] According to some embodiments of the present application, a battery cell 10 is provided. Figure 3 and Figure 4 The battery cell 10 includes: a shell 1a; at least one electrode assembly 3, which is accommodated in the shell 1a, and the electrode assembly 3 includes a pole piece, which includes a current collector 33 and an active material 34, and the current collector 33 includes a current collector body 31 and a plurality of pole tabs 32, the current collector body 31 is coated with the active material 34, and the pole tabs 32 are not coated with the active material 34; an electrode terminal 11, which is arranged in the shell 1a; a converter 4, which includes at least one connecting portion 42, and 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, and S1<S2.

[0060] 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 cover 1 covering an opening 21 of the shell 2 .

[0061] The current collector 33 refers to a structure that not only provides support for the active material layer, but also collects the current generated by the active material layer for external output. It can be a metal current collector 33, such as copper metal foil, aluminum metal foil, etc.; it can also be a composite current collector 33. The current collector body 31 refers to a structure in which the active material 34 is coated in the current collector 33, and the tab 32 refers to a structure in which the active material 34 is not coated in the current collector 33. When the current collector 33 is a metal current collector 33, the material of the tab 32 is also only a metal material. At this time, the minimum flow 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 flow cross section of the tab 32 is the sum of the cross sections of the conductive layer 332 on the insulating support layer 331, which 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, on the metal current collector 33 or the composite current collector 33 , 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 .

[0062] 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 the corresponding conductive layer 332 .

[0063] 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 oxides (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 、LiMn 2 O 4 ), 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 O 2 (Also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O 2 (Also referred to as NCM523 )、LiNi 0.5 Co 0.25 Mn 0.25 O 2 (Also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O 2 (Also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O 2 (Also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2 ) and its modified compounds, etc. Examples of lithium phosphates containing olivine structures may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), at least one of a composite material of lithium manganese phosphate and carbon, a composite material of lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0064] The negative electrode active material 34 may adopt the negative electrode active material 34 for the battery 100 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. The silicon-based material may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may include one or more of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional 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.

[0065] The connection portion 42 refers to a component connected between the pole tab 32 and the electrode terminal 11, and realizes current conduction between the pole tab 32 and the electrode terminal 11. When the current is too large during the cyclic charge and discharge process, since the minimum area of ​​the cross section of the connection portion 42 is less than the sum of the minimum areas of the cross sections of the pole tabs 32, the connection portion 42 is more likely to overheat and disconnect between the connection position of the electrode terminal 11 and the connection position of the pole tab 32, thereby blocking the flow of abnormal current and effectively reducing the damage to the electrode assembly 3 due to the temperature rise at the position of the pole tab 32.

[0066] 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 via an intermediate structure. Meanwhile, the tab 32 and the electrode terminal 11 may be connected on the adapter 4 by, but not limited to, welding.

[0067] In addition, the minimum cross-sectional area of ​​the connection portion 42 refers to the cross-sectional area of ​​the connection portion 42 perpendicular to the current flow direction in the current flow direction of the connection portion 42, and the cross-sectional area of ​​the connection portion 42 with the smallest area is the minimum cross-sectional area of ​​the connection portion 42. Figure 4 , the minimum flow cross section of the connection portion 42 is Figure 4 Similarly, the minimum cross-section of the pole lug 32 refers to the cross-section with the smallest area in the cross-section of the pole lug 32 perpendicular to the current flow direction in the current flow direction of the pole lug 32.

[0068] The sum of the areas of the minimum cross-sections of the pole tabs 32 S2 can be understood as follows: when stacking or winding, there are multiple pole tabs 32, and the pole tabs 32 of the same polarity are stacked together, such as: the positive pole tabs 321 are stacked together, and the negative pole tabs 322 are stacked together. During the charging and discharging process, the current will pass through each pole tab 32 connected to the same connection portion 42, so S2 is the sum of the areas of the minimum cross-sections of each pole tab 32 connected to the same connection portion 42.

[0069] With such a design, if an abnormal current occurs, such as an overly large current, the connection portion 42 located between the pole tab 32 and the electrode terminal 11 will break first before the pole tab 32, thereby disconnecting the current conduction between the adapter 4 and the pole tab 32, blocking the continuation of the abnormal current and reducing damage to the electrode assembly 3 due to the temperature rise at the pole tab 32, thereby improving the reliability of the battery cell 10.

[0070] According to some embodiments of the present application, optionally, please refer to Figure 5 and Figure 6 The material of the current collector 33 includes only metal elements, the minimum flow area of ​​a single pole ear 32 is S3, the number of pole ears 32 connected to the same connecting portion 42 is N, and S2 is equal to the product of S3 and N.

[0071] The material of the current collector 33 only includes metal elements, which means that the current collector 33 is a metal current collector 33, and its material can be aluminum, copper, etc. At this time, the current collector body 31 and the tab 32 only include metal elements. In this way, 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 current flow direction of the tab 32. The obtained cross section with the smallest area is the minimum flow cross section of the tab 32. You can refer to Figure 5 , the minimum flow cross section of a single pole ear 32 is Figure 5The section indicated by S3.

[0072] In some examples, the area S1 of the tab 32 also 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, b is a constant, 1≤b≤2. The position of the minimum width L of the tab 32 represents the position of the minimum current capacity of the tab 32, and the width of the tab 32 can be kept consistent in the protrusion extension direction T, that is, the tab 32 is a uniform width structure, which can be specifically referred to Figure 5 ; It may also be inconsistent, for example: the width of the pole ear 32 is wider as it is closer to the collector body 31 in the protruding extension direction T. For details, please refer to Figure 6 .

[0073] Among them, b is a constant, which is obtained through experience. Its main function is to ensure that the pole tab 32 can meet the overcurrent demand throughout its entire life cycle, because the pole tab 32 will be accompanied by degradation 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 pole tab 32, which can reduce the probability of damage to the pole tab 32. However, b≤2 limits b to a value that is 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 pole tab 32.

[0074] For ease of understanding, the total number of layers of positive electrode tabs 321 in a battery cell 10 (or electrode assembly 3) is 40, and the thickness H2 of the positive electrode tabs 321 connected to the same adapter 4 is 1 micrometer (μm); the minimum width of the positive electrode tab 321 is 100mm. At this time, the minimum cross-sectional area S1 < 4mm 2 / b. When b is 1, the minimum cross-sectional area S1 is less than 4 mm 2 .

[0075] 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.

[0076] Such a design makes the sum of the current carrying capacity of the tabs 32 connected to the same connecting part 42 greater than the current carrying capacity of the connecting part 42, thus protecting the positive pole tab 321 and reducing its damage when the current of the battery 100 is large, so that the battery 100 has good charging and discharging functions, thereby further improving the life and power performance of the battery 100.

[0077] According to some embodiments of the present application, optionally, please refer to Figure 8 and Fig. 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 pole tabs 32 is S4. The number of pole tabs 32 connected to the same connecting portion 42 is N, and S2 is equal to the product of S4 and N.

[0078] The insulating support layer 331 refers to a structure that supports the current collector 33, and its material can be selected from at least one of an organic polymer insulating material, an inorganic insulating material, and a composite material. Among them, 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.

[0079] The conductive layer 332 refers to a structure with a conductive function, which can collect the current generated by the active material layer for external output. At the same time, in the pole piece, 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., 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 pole piece formed is a positive pole piece; when one side of the conductive layer 332 is coated with materials such as graphite, silicon oxide, etc., the pole piece formed is a negative pole piece.

[0080] The conductive layer 332 may be copper foil or 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 .

[0081] When the current collector 33 is a composite current collector 33, since the insulating support layer 331 is an insulating material and current cannot pass through it, the minimum current cross-section on the pole ear 32 should be the sum of the minimum current cross-sections on the conductive layers 332 on both sides of the insulating support layer 331, wherein the current collector body 31 and the pole ear 32 both include an insulating support layer 331 and a conductive layer 332 arranged on both sides of the insulating support layer 331.

[0082] Similarly, in some examples, the area S1 of the tab 32 also satisfies the condition: S1<(L×H2×N) / b; wherein L is the minimum width of the tab 32, H2 is the sum of the thicknesses of the conductive layer 332 on both sides of the tab 32, which is equal to Fig. 9 H0 minus H3. b is a constant, 1≤b≤2. The position of the minimum width L of the tab 32 represents the position of the minimum current capacity of the tab 32. The width of the tab 32 can be kept consistent in the protrusion extension direction T, that is, the tab 32 is a uniform width structure. For details, please refer to Figure 8 In addition, in some other embodiments, b also satisfies the condition: 1.333≤b≤1.67, for example: it may be but 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.

[0083] Such a design makes the sum of the current carrying capacity of the tabs 32 connected to the same connecting portion 42 greater than the current carrying capacity of the connecting portion 42, thus protecting the positive pole tab 321 and reducing its damage when the current of the battery 100 is large, so that the battery 100 with the composite current collector 33 has good charging and discharging functions, thereby further improving the life and power performance of the battery 100.

[0084] According to some embodiments of the present application, optionally, please refer to Figure 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 .

[0085] The transition metal foil 35 refers to 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 may be, but is not limited to, aluminum, copper, and the like.

[0086] 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.

[0087] According to some embodiments of the present application, optionally, please refer to Figure 4 , Figure 8 and Fig. 9 The transition metal foil 35 is welded to the electrode ear 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 transition metal foil 35 between the first weld mark 36 and the second weld mark 37 is S5, S5>S1.

[0088] The first weld mark 36 refers to welding between the transition metal foil 35 and the tab 32, and a weld structure is formed between the two. The second weld mark 37 refers to welding between the transition metal foil 35 and the connection part 42, and a weld structure is formed between the two. During the charge and discharge process, the current will flow between the first weld mark 36 and the second weld mark 37. For this reason, the area of ​​the minimum cross-sectional area of ​​the transition metal foil 35 is larger than the area of ​​the minimum cross-sectional area of ​​the connection part 42, so that the bottleneck of the current flow of the battery cell 10 is concentrated on the connection part 42, so that when the current abnormality occurs, it is easy to fuse on the connection part 42.

[0089] The minimum current 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 .

[0090] 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 area 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 be blown.

[0091] With such a design, if an abnormal current occurs, such as an overly large current, the connection portion 42 located between the adapter metal foil 35 and the electrode terminal 11 will break first before the pole tab 32, thereby disconnecting the current conduction between the adapter 4 and the pole tab 32, blocking the continuation of the abnormal current, and reducing the damage to the electrode assembly 3 due to the temperature rise at the position of the pole tab 32, thereby improving the reliability of the battery cell 10.

[0092] According to some embodiments of the present application, optionally, refer to Fig. 9 , the thickness of the conductive layer 332 of the current collector body 31 is H1, 300nm≤H1≤4000nm.

[0093] The thickness of the conductive layer 332 in the current collector 33 is 300nm to 4000nm, and as an example, it can be, but not limited to, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, 1500nm, 1800nm, 2000nm, 2200nm, 2500nm, 3000nm, 3500nm, 4000nm. Of course, in some other embodiments, the thickness of the conductive layer 332 can also be 800nm ​​to 2000nm, and as an example, it can be, but not limited to, 800nm, 850nm, 900nm, 950nm, 1000nm, 1200nm, 1400nm, 1600nm, 1800nm, 2000nm, etc.

[0094] The thickness of the conventional pure metal layer current collector 33 is generally about 10 microns. As an example, the conventional positive electrode current collector 33 generally adopts a pure aluminum foil with a thickness of 13 microns. In the present application, the thickness of the conductive layer 332 in the composite current collector 33 is controlled within the above range, so that the current collector 33 has good conductivity, reduces the internal resistance of the battery 100, and further improves the mass energy density of the battery 100 on the basis of the same weight.

[0095] In addition, the thickness of the conductive layer 332 of the tab 32 is also controlled to be between 300 nm and 4000 nm.

[0096] With such a design, the thickness of the conductive layer 332 of the current collector body 31 is controlled between 300nm and 4000nm, so that the current collector 33 has good conductivity, reduces the internal resistance of the battery 100, and further improves the mass energy density of the battery 100 on the basis of the same weight.

[0097] 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.

[0098] 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.

[0099] The aluminum metal material may be, but is not limited to, single-element aluminum, aluminum alloy, a laminate of single-element aluminum and aluminum alloy, etc. Meanwhile, the copper metal material may be, but is not limited to, single-element copper, copper alloy, a laminate of single-element copper and copper alloy, etc.

[0100] With such a design, the material of the conductive layer 332 is reasonably selected, and a battery cell 10 with stable performance is designed.

[0101] According to some embodiments of the present application, optionally, the material of the insulating support layer 331 includes a polymer material.

[0102] The polymer material includes, but is 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.

[0103] In addition, the material of the insulating support layer 331 includes not only polymer materials but also some additives to form 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 their alloys. Optionally, the inorganic non-metallic material includes one or more of graphite, conductive carbon, aluminum oxide, silicon oxide, silicon carbide and silicon dioxide.

[0104] Such a design makes the structure of the composite current collector 33 more stable and reliable.

[0105] According to some embodiments of the present application, optionally, refer to Figure 8 and Fig. 9 , the tab 32 is disposed 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, the thickness of the conductive layer 332 of the current collector body 31 is H1, wherein, 10 5 ≤A / H1≤3×10 5 .

[0106] The length of the current collector body 31 in the preset direction P can affect the current distribution density on the current collector 33. For example, the longer the length of 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, when designing the structure, for a current collector 33 with a larger length of the current collector body 31 along the preset direction P, the thickness of its conductive layer 332 is correspondingly increased; for a current collector 33 with a smaller length of the current collector body 31 along the preset direction P, the thickness of its conductive layer 332 is correspondingly reduced.

[0107] 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.

[0108] In this way, when designing, increasing the length of the current collector body 31 may 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 .

[0109] According to some embodiments of the present application, optionally, the length A satisfies the condition: 150mm≤A≤1500mm.

[0110] The length A of the current collector body 31 in the preset direction P may be between 150 mm and 1500 mm. For example, the length A may be 150 mm, 200 mm, 300 mm, 400 mm, 600 mm, 800 mm, 1000 mm, 1200 mm, 1500 mm, etc.

[0111] In addition, the thickness of the conductive layer 332 may 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 is small, and the substrate is easily damaged during the production process. At the same time, if the thickness is too small, the tensile strength and compressive deformation of the conductive layer 332 will be reduced. For this reason, the thickness H1 can be between 300nm and 4000nm. For example, the thickness H1 can be, but not limited to, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, 2000nm, 3000nm, 4000nm, etc.

[0112] 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.

[0113] According to some embodiments of the present application, optionally, refer to Figure 3 The electrode assembly 3 includes at least two, each electrode assembly 3 is stacked in sequence along its own thickness direction, the adapter 4 includes a plurality of connecting parts 42, and the plurality of tabs 32 on each electrode assembly 3 are respectively connected to the connecting parts 42.

[0114] The electrode assemblies 3 are stacked one by one, so that the overall volume of the battery cell 10 will not be excessively increased while increasing the electric capacity. It is not difficult to understand 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 of the adapters 4, and the negative tab 322 on each electrode assembly 3 is connected to the other adapter 4.

[0115] 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 overlapped and distributed with its cylindrical side surface.

[0116] With such a 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.

[0117] According to some embodiments of the present application, optionally, refer to Figure 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 .

[0118] The confluence part 41 refers to a part on the adapter 4 that is connected to the electrode terminal 11. In this way, during the charge and discharge process, the current on each tab 32 is converged on the confluence part 41 through the corresponding connection part 42, and then uniformly flows to the electrode terminal 11 from the confluence part 41; or, the current on the electrode terminal 11 is diverted from the confluence part 41 to the connection part 42, and then flows from the connection part 42 to the tab 32.

[0119] Since the connection parts 42 are spaced apart on the confluence part 41, the flow bottleneck of the adapter 4 is distributed on each connection part 42. In some examples, in the spacing direction Z between the connection parts 42, the connection parts 42 at both ends do not extend beyond the ends of the confluence part 41 along the spacing direction Z, that is, the spacing between the two sides of the connection parts 42 at both ends facing away from each other is less than or equal to the spacing between the two ends of the confluence part 41 along the spacing direction Z.

[0120] Meanwhile, the number of the connecting parts 42 may not be limited to Figure 4 In the figure, there are two, but there 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, that is, one connecting portion 42 may be connected to the tabs 32 of multiple electrode assemblies 3 at the same time.

[0121] 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 .

[0122] With such a design, when the current increases abnormally, the adapter 4 can break at each connection portion 42, thereby effectively protecting the electrode assembly 3 from damage.

[0123] 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.

[0124] It can be seen that the square battery cell 10 may have one end cover 1 , that is, the shell 2 has an opening 21 ; or may have two end covers 1 , which are respectively covered on the openings 21 at opposite ends of the shell 2 .

[0125] The end cap 1 refers to a component that covers the opening 21 of the housing 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 housing 2 to match the housing 2. The housing 2 is a component used to match 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.

[0126] Such a design can effectively reduce the damage of the battery cell 10 having one end cover 1 or two end covers 1 caused by the temperature rise at the position of the tab 32 , thereby improving the reliability of the battery cell 10 .

[0127] 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 an aluminum-plastic film.

[0128] 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, such as: in contact with the shell 1a.

[0129] Such a design can effectively reduce the damage of the soft-pack battery caused by the temperature rise at the position of the tab 32 , thereby improving the reliability of the battery cell 10 .

[0130] According to some embodiments of the present application, optionally, the shape of the outer shell 1a is a cylinder, and the outer shell 1a includes a shell body 2 and at least one end cover 1, the end cover 1 covers the opening 21 of the shell body 2, and the outer diameter of the cylinder is greater than or equal to 30 mm.

[0131] 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.

[0132] Such a design can effectively reduce the damage caused by the temperature rise at the position of 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.

[0133] According to some embodiments of the present application, the present application provides a battery 100 , and the battery 100 includes any one of the above battery cells 10 .

[0134] According to some embodiments of the present application, optionally, the present application provides an electrical device, and the electrical device includes the above battery 100.

[0135] According to some embodiments of this application, please refer to Figures 1 to 4 ,as well as Figure 8 and Fig. 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 a plurality of positive pole tabs 321. The adapter 4 includes a connecting portion 42 connected between the positive pole tab 321 and the electrode terminal 11. The area of ​​the minimum current cross section of the connecting portion 42 is S1, the minimum width of the positive pole tab 321 is L, the sum of the thickness of the conductive layer 332 on the positive pole tab 321 is H2, and N is the total number of layers of the positive pole tab 321 connected to the same adapter 4. Wherein, S1<(L×H2×N) / b; wherein, b is a constant, 1≤b≤2.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: The battery cell comprises: Housing (1a); At least one electrode assembly (3) is contained 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) being not coated with the active material (34); An electrode terminal (11) is arranged on the housing (1a); The adapter (4) comprises at least one connecting portion (42), wherein the connecting portion (42) is used to connect the electrode tab (32) and the electrode terminal (11); The area of ​​the minimum flow cross section of the connecting portion (42) is S1, the sum of the areas of the minimum flow cross sections of the pole lugs (32) connected to the same connecting portion (42) is S2, and S1<S2.

2. The battery cell according to claim 1, characterized in that: 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, characterized in that: The current collector (33) comprises 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 lugs (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, characterized in that: The current collector (33) further comprises a transition metal foil (35), wherein 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, characterized in that: The transition metal foil (35) is welded to the electrode 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.

6. The battery cell according to claim 3, characterized in that: The thickness of the conductive layer (332) of the current collector body (31) is H1, 300nm≤H1≤4000nm.

7. The battery cell according to claim 3, characterized in that: The material of the conductive layer (332) includes one of aluminum metal material and copper metal material.

8. The battery cell according to claim 3, characterized in that: The material of the insulating support layer (331) includes polymer material.

9. The battery cell according to claim 3, characterized in that: The pole ear (32) is arranged 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, characterized in that: The length A satisfies the condition: 150mm≤A≤1500mm.

11. The battery cell according to any one of claims 1 to 10, characterized in that: 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, characterized in that: The adapter (4) comprises a converging portion (41) connected to the connecting portion (42), the connecting portion (42) is connected to the electrode tab (32) on the electrode assembly (3), and the converging portion (41) is connected to the electrode terminal (11).

13. The battery cell according to any one of claims 1 to 10, characterized in that: The outer shell (1a) is square in shape, and comprises a shell (2) and at least one end cover (1), the shell (2) has an opening (21) at only one end, and the end cover (1) covers 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 10, characterized in that: The outer shell (1a) is a soft package structure, and the material of the outer shell (1a) includes an aluminum-plastic film.

15. The battery cell according to any one of claims 1 to 10, characterized in that: 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, characterized in that: The battery comprises the battery cell according to any one of claims 1 to 15.

17. An electrical device, characterized in that: The electrical device comprises the battery according to claim 16.

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