Battery monomer, battery device and electric device

Abstract

The utility model discloses a battery monomer, a battery device and a power utilization device, and the battery monomer comprises a battery monomer which comprises a shell and an electrode assembly; the electrode assembly is arranged in the shell and comprises a pole piece, the pole piece is wound to form a straight section and bent sections located on the two sides of the straight section in the first direction, each bent section comprises an inflection point section and transition sections located on the two sides of the inflection point section in the second direction, and the transition sections are connected between the straight section and the inflection point sections; the pole piece comprises a current collector and an active material layer arranged on at least one side of the current collector in the thickness direction, and the thickness of at least part of the active material layer located at the inflection point section is smaller than that of at least part of the active material layer located at the transition section, so that the distance between the active material layer at the inflection point section and the isolating membrane can be increased; the good infiltration performance between the electrolyte and the active material layer is improved, the risk of lithium precipitation is reduced, and the reliability of the battery monomer is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, battery device, and power supply device. Background Technology

[0002] With the development of new energy technologies, battery cells are being used more and more widely, for example in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools.

[0003] As batteries are used in a wider range of applications, the requirements for the reliability of individual battery cells are becoming increasingly stringent. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical device that can improve the reliability of the battery cell.

[0005] In a first aspect, this application provides a battery cell, including: a housing and an electrode assembly; the electrode assembly is disposed within the housing, the electrode assembly including an electrode sheet, the electrode sheet being wound to form a straight section and a bent section located on both sides of the straight section along a first direction, the bent section including an inflection point section and a transition section on both sides of the inflection point section in a second direction, the transition section connecting the straight section and the inflection point section; the electrode sheet including a current collector and an active material layer disposed on at least one side in the thickness direction of the current collector, the thickness of at least a portion of the active material layer located in the inflection point section being less than the thickness of at least a portion of the active material layer located in the transition section, the first direction and the second direction being intersecting.

[0006] In this embodiment, the thickness of at least a portion of the active material layer located at the inflection point is less than the thickness of at least a portion of the active material layer located in the transition section. This can increase the spacing between the active material layer at the inflection point and the separator, improve the wettability between the electrolyte and the active material layer, and reduce the risk of lithium plating due to the small spacing between the active material layer at the inflection point and the separator after expansion, thereby improving the reliability of the battery cell.

[0007] According to embodiments of this application, the active material layer includes a first main body portion and a first recess portion. The thickness of the first recess portion is less than the thickness of the main body portion, and at least a portion of the first recess portion is located at an inflection point segment. Having at least a portion of the first recess portion located at an inflection point segment can increase the gap between the active material layer and the separator at the inflection point segment, reducing the risk of lithium plating.

[0008] According to embodiments of this application, the first recess is located in the middle of the electrode along a third direction, and the first main body is located on both sides of the first recess along the third direction; or, the first recess extends through the electrode along the third direction; the first direction, the second direction, and the third direction intersect each other. The middle of the inflection point segment along the third direction has a relatively high concentration of lithium ions, resulting in a greater risk of lithium plating. The first recess being located in the middle of the electrode along the third direction improves the lithium plating problem. The inflection point segment extends along the third direction, and the first recess is located at the inflection point segment and extends through the electrode along the third direction, thereby improving the risk of lithium plating at the inflection point segment.

[0009] According to the embodiments of this application, the first recess extends through the electrode sheet along its length direction. Providing a first recess that extends through the length direction of the electrode sheet helps to simplify the manufacturing process and improve the efficiency of battery cell manufacturing.

[0010] According to the embodiments of this application, the electrode includes a plurality of first recesses, at least some of which are located at inflection points, which can reduce the arrangement area of ​​the first recesses and reduce the impact of the first recesses on the energy density of the battery cell.

[0011] According to embodiments of this application, the electrode includes an anode sheet and a cathode sheet, each including a current collector and active material layers disposed on both sides of the current collector in the thickness direction. The anode sheet is wound to form a first concave surface and a first convex surface located in the bending section, with a first recess located on at least one of the first convex surface and the first concave surface; and / or, the cathode sheet is wound to form a second concave surface and a second convex surface located in the bending section, with a first recess located on at least one of the second convex surface and the second concave surface. When the first recess is disposed on the first convex surface, it is beneficial to increase the distance between the inflection point segment of the first convex surface and the separator, improving the wettability of the inflection point segment. When the first recess is disposed on the first concave surface, it increases the distance between the inflection point segment of the first concave surface and the separator, improving the wettability of the inflection point segment and reducing the risk of lithium plating. The second convex surface is disposed adjacent to the first concave surface, and the first recess is disposed on the second convex surface, which can reduce the mass of the active material in the inflection point segment of the second convex surface and improve the lithium plating problem on the first concave surface. When the first concave portion is disposed on the second concave surface, and the second concave surface is disposed adjacent to the first convex surface, the first concave portion disposed on the second concave surface can reduce the mass of active material at the inflection point of the second concave surface and improve the lithium plating problem of the first convex surface.

[0012] According to the embodiments of this application, the thickness difference between the first recess and the first main body is 1 micrometer to 30 micrometers, which improves the lithium plating problem while reducing the impact of the first recess on the energy density of the battery cell.

[0013] According to embodiments of this application, the active material layer includes a second main body portion and protrusions, the thickness of which is greater than the thickness of the second main body portion, and at least two protrusions are located on both sides of the inflection point segment along the length of the electrode. When the active material layer expands, the protrusions preferentially contact the separator membrane compared to the inflection point segment, reducing the tendency for the active material layer in the inflection point segment to continue expanding, maintaining a distance between the active material layer in the inflection point segment and the separator membrane, and improving the wettability of the electrode.

[0014] According to the embodiments of this application, the protrusion is located in the middle of the electrode along a third direction, or the protrusion is disposed through the electrode along a third direction; the first direction, the second direction, and the third direction intersect each other. The inflection point segment along the middle of the third direction has a relatively high concentration of lithium ions, which poses a greater risk of lithium plating. The protrusion being located in the middle of the electrode along the third direction or being disposed through the electrode along the third direction improves the lithium plating problem.

[0015] According to the embodiments of this application, the protrusion penetrates the electrode along the length direction of the electrode. Providing a protrusion that penetrates the length direction of the electrode helps to simplify the manufacturing process and improve the manufacturing efficiency of battery cells.

[0016] According to the embodiments of this application, the electrode includes a plurality of protrusions, at least some of which are located on both sides of the inflection point segment along the length of the electrode, thereby reducing the arrangement area of ​​the protrusions and reducing the impact of the protrusions on the energy density of the battery cell.

[0017] According to embodiments of this application, the second main body includes a first segment and a second segment. The second segment is located between two adjacent protrusions, and at least a portion of the second segment is located at an inflection point. The first segment is located on the side of the protrusion facing away from the second segment. The thickness of the second segment is less than the thickness of the protrusion, or the thickness of the second segment is less than the thickness of the first segment. The fact that the second segment is located between two adjacent protrusions and its thickness is less than the thickness of the protrusion or the first segment increases the distance between the second segment and the separator, improves the wettability of the second segment, and mitigates the lithium plating problem at the inflection point.

[0018] According to embodiments of this application, the electrode includes an anode sheet, which includes a current collector and active material layers disposed on both sides of the current collector in the thickness direction. The anode sheet is wound to form a first concave surface and a first convex surface located in the bending section. A second main body portion and a convex portion are located on at least one of the first convex surface and the first concave surface. When the second main body portion and the convex portion are disposed on the first convex surface, the distance between the active material layer and the separator on the first convex surface is increased, improving the wettability of the active material layer and reducing the risk of lithium plating. When the convex portion is disposed on the first concave surface, the distance between the active material layer and the separator on the first concave surface is increased, improving the wettability of the active material layer and reducing the risk of lithium plating.

[0019] Secondly, this application provides a battery device including a battery cell according to any embodiment of the first aspect.

[0020] Thirdly, this application provides an electrical device, including the battery device in the second aspect embodiment. Attached Figure Description

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0022] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0023] Figure 2 Exploded view of the battery device according to some embodiments of this application;

[0024] Figure 3 This is a schematic diagram of the structure of a battery module according to some embodiments of this application;

[0025] Figure 4 This is a schematic diagram of the exploded structure of a battery cell according to some embodiments of this application;

[0026] Figure 5 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0027] Figure 6 This is a schematic diagram of the structure of a battery cell according to other embodiments of this application;

[0028] Figure 7 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0029] Figure 8 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0030] Figure 9 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0031] Figure 10 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0032] Figure 11 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0033] Figure 12 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0034] Figure 13 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0035] Figure 14 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0036] Figure 15 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0037] Figure 16 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0038] Figure 17 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0039] Figure 18 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application.

[0040] Figure label:

[0041] 1. Vehicles;

[0042] 10. Battery assembly; 11. Battery cell; 20. Control system; 30. Motor; 40. Housing; 41. First housing section; 42. Second housing section; 43. Receiving section; 50. Battery module;

[0043] 100, Housing; 101, Opening; 110, Top cover assembly; 200, Electrode assembly; 210, Electrode sheet; 211, Straight section; 212, Bending section; 212a, Inflection point section; 212b, Transition section; 220, Current collector; 230, Active material layer; 231, First main body; 232, First recess; 233, Second main body; 233a, First segment; 233b, Second segment; 234, Protrusion; 240, Anode sheet; 241, First concave surface; 242, First convex surface; 250, Cathode sheet; 251, Second concave surface; 252, Second convex surface; 300, Separating membrane; X, First direction; Y, Second direction; Z, Third direction; N, Length direction; M, Thickness direction. Detailed Implementation

[0044] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0046] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0047] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0049] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0050] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0051] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0052] Currently, judging from market trends, the application of battery devices is becoming increasingly widespread. Battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely applied in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery device applications, market demand is also constantly increasing.

[0053] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0054] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0055] A battery cell includes electrode components and an electrolyte. The electrode components include a cathode plate, an anode plate, and a separator. The battery cell primarily functions by the movement of metal ions between the cathode and anode plates. The cathode plate includes a cathode current collector and a cathode active material layer, the active material layer being coated on the surface of the cathode current collector. The cathode current collector includes a cathode current collector section and a cathode tab connected to the cathode current collector section. The cathode current collector section is coated with the cathode active material layer, while the cathode tab is not coated with the cathode active material layer. Taking a lithium-ion battery as an example, the cathode current collector can be made of aluminum, and the cathode active material layer includes cathode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The anode plate includes an anode current collector and an anode active material layer, the active material layer being coated on the surface of the anode current collector. The anode current collector includes an anode current collector section and an anode tab connected to the anode current collector section. The anode current collector section is coated with the anode active material layer, while the anode tab is not coated with the anode active material layer. The anode current collector can be made of copper, and the anode active material layer includes anode active material, which can be carbon or silicon, etc.

[0056] The housing may contain one or more electrode assemblies, which are mainly formed by winding or stacking electrode sheets. During the charging and discharging process of the battery, the cathode active material layer and the anode active material layer react with the electrolyte, and the electrode tabs connect to the electrode terminals to form a current loop. The housing is a component used to cooperate with the top cover assembly to form the internal environment of the battery cell, wherein the formed internal environment can be used to accommodate the electrode assembly, electrolyte, and other components. The housing and the top cover assembly can be independent components, and an opening can be provided on the housing. The top cover assembly closes the opening to form the internal environment of the battery cell. Optionally, the top cover assembly and the housing can be integrated. Optionally, the top cover assembly and the housing can form a common connection surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing, the top cover assembly closes the housing. The housing can be made of various materials, including copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0057] In related technologies, a prerequisite for efficient reaction between the electrolyte and the active material layer in the electrode of a battery cell is good wetting performance between the electrolyte and the electrode. Insufficient electrolyte in the electrode can lead to lithium plating and other issues, resulting in a decrease in the capacity of the battery cell. Furthermore, a larger accumulation of active material layer in the inflection point section formed after electrode winding on the cathode can easily cause lithium plating on the active material layer of the anode at this inflection point.

[0058] To address the aforementioned technical problems, this application provides a technical solution whereby a battery cell includes a casing and an electrode assembly. The electrode assembly includes an electrode sheet, which in turn includes a current collector and an active material layer disposed on at least one side of the current collector in the thickness direction. The thickness of at least a portion of the active material layer located at the inflection point is less than the thickness of at least a portion of the active material layer located in the transition section, thereby increasing the spacing between the active material layer and the separator, improving wettability, and thus enhancing the performance of the battery cell. When the thickness of at least a portion of the active material layer on the cathode located at the inflection point is less than the thickness of at least a portion of the active material layer located in the transition section, the mass of the active material layer on the cathode can be reduced, thus reducing the risk of lithium plating on the corresponding anode at the inflection point.

[0059] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0060] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0061] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0062] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0063] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0064] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0065] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0066] The technical solutions described in this application are applicable to battery devices and electrical devices using battery devices. Electrical devices include, for example, mobile phones, portable devices, laptops, electric vehicles, electric cars, ships, spacecraft, electric toys, and power tools. Spacecraft include, for example, airplanes, rockets, space shuttles, and spacecraft. Electric toys include, for example, stationary or mobile electric toys, specifically, game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include, for example, metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, specifically, electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0067] The battery cells described in this application are not limited to the electrical devices described above, but for the sake of brevity, the following embodiments are all illustrated using electric vehicles as an example.

[0068] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle provided in an embodiment of this application.

[0069] Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 10 can be installed inside vehicle 1, specifically, for example, at the bottom, front, or rear of vehicle 1. The battery device 10 can be used to power vehicle 1; for example, it can serve as the operating power source for vehicle 1. Vehicle 1 may also include a control system 20 and a motor 30. The control system 20, for example, controls the battery device to supply power to the motor 30. The battery device can be used for starting and navigation of vehicle 1. Of course, the battery device 10 can also be used to drive vehicle 1, replacing or partially replacing gasoline or natural gas as the driving force for vehicle 1.

[0070] Figure 2 This is an exploded structural diagram of a battery device provided in an embodiment of this application. Figure 2 As shown, the battery device 10 includes a housing 40 and battery cells (not shown in the figure), with the battery cells housed within the housing 40.

[0071] The housing 40 is used to house individual battery cells, and the housing 40 can have various structures. In some embodiments, the housing 40 may include a first housing portion 41 and a second housing portion 42, which overlap each other, and together define a receiving portion 43 for housing the individual battery cells. The second housing portion 42 may be a hollow structure with one end open, and the first housing portion 41 may be a plate-like structure, with the first housing portion 41 covering the open side of the second housing portion 42 to form a housing with the receiving portion 43; alternatively, both the first housing portion 41 and the second housing portion 42 may be hollow structures with one side open, with the open side of the first housing portion 41 covering the open side of the second housing portion 42 to form a housing 40 with the receiving portion 43. Of course, the first housing portion 41 and the second housing portion 42 can have various shapes, such as cylinders, cuboids, etc.

[0072] In the battery device 10, there can be multiple battery cells. These multiple battery cells can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells are connected in both series and parallel configurations. Multiple battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed within the housing 40. Alternatively, multiple battery cells can first be connected in series, parallel, or in a mixed configuration to form a battery module 50, and then multiple battery modules 50 can be connected in series, parallel, or in a mixed configuration to form a whole and housed within the housing 40.

[0073] Figure 3 This is a schematic diagram of the structure of a battery module provided in an embodiment of this application.

[0074] In some embodiments, such as Figure 3As shown, there are multiple battery cells 11, which are first connected in series, parallel, or in a mixed manner to form a battery module 50. The multiple battery modules 50 are then connected in series, parallel, or in a mixed manner to form a whole, which is housed in the casing.

[0075] Firstly, such as Figures 4 to 7 As shown, this application proposes a battery cell 11, including: a housing 100 and an electrode assembly 200; the electrode assembly 200 is disposed within the housing 100, and the electrode assembly 200 includes an electrode sheet 210, the electrode sheet 210 being wound to form a straight section 211 and a bent section 212 located on both sides of the straight section 211 along a first direction X, the bent section 212 including an inflection point section 212a and a transition section 212b on both sides of the inflection point section 212a in a second direction Y, the transition section 212b connecting the straight section 211 and the inflection point section 212a; the electrode sheet 210 includes a current collector 220 and an active material layer 230 disposed on at least one side in the thickness direction M of the current collector 220, the thickness of at least a portion of the active material layer 230 located in the inflection point section 212a is less than the thickness of at least a portion of the active material layer 230 located in the transition section 212b, and the first direction X and the second direction Y are intersecting.

[0076] For example, the active material layer 230 may be disposed on one side of the current collector 220 in the thickness direction M, or the active material layer 230 may be disposed on both sides of the current collector 220 in the thickness direction M.

[0077] For example, electrode 210 may include anode sheet 240, wherein the thickness of at least a portion of the active material layer 230 of anode sheet 240 located at inflection point segment 212a is less than the thickness of at least a portion of the active material layer 230 located at transition segment 212b.

[0078] For example, electrode 210 may include cathode sheet 250, wherein the thickness of at least a portion of the active material layer 230 of cathode sheet 250 located at inflection point segment 212a is less than the thickness of at least a portion of the active material layer 230 located at transition segment 212b.

[0079] For example, the thickness of at least a portion of the active material layer 230 located in the inflection point segment 212a is less than the thickness of at least a portion of the active material layer 230 located in the transition segment 212b. This can be achieved by the thickness of the active material layer 230 located in the inflection point segment 212a being entirely less than the thickness of the active material layer 230 located in the transition segment 212b.

[0080] For example, the thickness of at least a portion of the active material layer 230 located in the inflection point segment 212a is less than the thickness of at least a portion of the active material layer 230 located in the transition segment 212b. This can be achieved by the thickness of the active material layer 230 located in the partial inflection point segment 212a being less than the thickness of the active material layer 230 located in the transition segment 212b.

[0081] For example, the thickness of at least a portion of the active material layer 230 located in the inflection point segment 212a is less than the thickness of at least a portion of the active material layer 230 located in the transition segment 212b. This can be achieved by the thickness of the active material layer 230 located in the inflection point segment 212a being less than the thickness of the active material layer 230 located in the transition segment 212b.

[0082] In this embodiment, the battery cell 11 includes a housing 100 and an electrode assembly 200, which is located within the housing 100 and undergoes electrochemical reactions. An active material layer 230 is coated on at least one side of the current collector 220. During the charging and discharging process of the battery cell 11, the active material layer 230 reacts with the electrolyte. The electrode sheet 210 is wound to form a straight section 211 and bent sections 212 located on both sides of the straight section 211 along a first direction X. The bent sections 212 include inflection point sections 212a and transition sections 212b on both sides of the inflection point sections 212a along a second direction Y. The curvatures of the inflection point sections 212a are opposite on both sides along the length direction N of the electrode sheet 210. The thickness of at least a portion of the active material layer 230 located in the inflection point segment 212a is less than the thickness of at least a portion of the active material layer 230 located in the transition segment 212b, thereby increasing the spacing between the active material layer 230 in the inflection point segment 212a and the separator 300, improving the good wetting performance between the electrolyte and the active material layer 230, reducing the risk of lithium plating due to the small spacing between the active material layer 230 and the separator 300 after the inflection point segment 212a expands, thereby improving the reliability of the battery cell 11.

[0083] When electrode 210 is wound along its length direction N, transition section 212b is located on both sides of inflection section 212a along the length direction N of electrode 210. In straight section 211, the length direction N of electrode 210 is parallel to the first direction X; in inflection section 212a and transition section 212b, the length direction of electrode is the winding direction. In straight section 211, the thickness direction of active material layer 230 is perpendicular to the first direction X; in inflection section 212a and transition section 212b, the thickness direction is perpendicular to the tangent of the bending path.

[0084] Optionally, the housing 100 includes a third-direction Z-shaped opening 101, and the battery cell 11 also includes a top cover assembly 110 that closes to the opening 101.

[0085] Optional, such as Figure 5 As shown, the electrode 210 includes an anode plate 240 and a cathode plate 250, which are arranged adjacent to each other, and a separator 300 is provided between the anode plate 240 and the cathode plate 250.

[0086] like Figures 6 to 8As shown, in some optional embodiments, the active material layer 230 includes a first main body portion 231 and a first recess portion 232, the thickness of the first recess portion 232 is less than the thickness of the main body portion, and at least a portion of the first recess portion 232 is located at the inflection point segment 212a.

[0087] For example, the first recess 232 may be located on the anode plate 240 or the cathode plate 250.

[0088] In these optional embodiments, the thickness of the first recess 232 is less than the thickness of the main body. When the electrode 210 is wound to form the inflection segment 212a, at least a portion of the first recess 232 is located in the inflection segment 212a, which can increase the gap between the active material layer 230 and the separator 300 in the inflection segment 212a, reducing the risk of lithium plating. When the first recess 232 is located in the cathode sheet 250, the mass of the active material layer 230 of the cathode sheet 250 in the inflection segment 212a can be reduced, reducing the amount of lithium ions transported from the active material layer 230 of the cathode sheet 250 to the active material layer 230 of the anode sheet 240, thus improving the lithium plating problem of the anode sheet 240.

[0089] like Figure 6 and Figure 7 As shown, in some optional embodiments, the first recess 232 is located in the middle of the electrode 210 along the third direction Z, and the first main body portion 231 is located on both sides of the first recess 232 along the third direction Z; the first direction X, the second direction Y and the third direction Z intersect each other.

[0090] In these optional embodiments, the inflection segment 212a has transition segments 212b on both sides along the second direction Y, and the inflection segment 212a extends along the third direction Z. The middle part of the inflection segment 212a along the third direction Z has a relatively high concentration of lithium ions, where the risk of lithium plating is greater. The first recess 232 is located in the middle of the electrode 210 along the third direction Z, thereby improving the lithium plating problem. When the first recess 232 is located on the cathode 250, it can reduce the mass of the active material layer 230 of the cathode 250 at the inflection segment 212a, reducing the amount of lithium ions transported from the active material layer 230 of the cathode 250 to the active material layer 230 of the anode 240, thus improving the lithium plating problem of the anode 240. When the first recess 232 is located on the anode 240, it can increase the distance between the anode 240 and the separator 300, improving the wettability between the anode 240 and the electrolyte, thus improving the lithium plating problem of the anode 240.

[0091] like Figure 8 As shown, in some alternative embodiments, the first recess 232 is disposed through the electrode 210 along the third direction Z.

[0092] In these alternative embodiments, the inflection point segment 212a extends along the third direction Z, and the first recess 232 is located in the inflection point segment 212a and is disposed through the electrode 210 along the third direction Z, thereby improving the risk of lithium plating in the inflection point segment 212a.

[0093] like Figure 6 , Figure 9 and Figure 10 As shown, in some alternative embodiments, the first recess 232 extends through the electrode 210 along the length direction N of the electrode 210.

[0094] In these optional embodiments, the electrode 210 is wound along its length direction N to form a straight section 211 and a bent section 212. The first recess 232 penetrates the electrode 210 along its length direction N, such that the first recess 232 passes through each inflection point section 212a. Providing a first recess 232 penetrating the length direction N of the electrode 210 simplifies the manufacturing process and improves the manufacturing efficiency of the battery cell 11. Optionally, there can be multiple first recesses 232, arranged side-by-side along a third direction Z. Providing multiple first recesses 232 can further improve the lithium plating problem. The space between two adjacent first recesses 232 forms a first main body portion 231. Spacing between adjacent first recesses 232 reduces the impact of the first recesses 232 on the structural rigidity of the active material layer 230.

[0095] like Figures 9 to 11 As shown, in some optional embodiments, the electrode 210 includes a plurality of first recesses 232, at least some of which are located at the inflection point segment 212a.

[0096] For example, such as Figure 9 and Figure 10 As shown, the multiple first recesses 232 can be arranged along the length direction N of the electrode 210, and some of the first recesses 232 are located at the inflection point segment 212a.

[0097] For example, such as Figure 9 and Figure 10 As shown, the multiple first recesses 232 can be arranged along the length direction N of the electrode 210, with some first recesses 232 located in the inflection point segment 212a, some first recesses 232 located in the transition segment 212b, and some first recesses 232 located in the straight segment 211.

[0098] For example, such as Figure 11 As shown, at least some of the first recesses 232 are located at the inflection point segment 212a, which means that all the first recesses 232 are located at the inflection point segment 212a.

[0099] In these alternative embodiments, the electrode 210 is provided with a plurality of first recesses 232, and at least some of the first recesses 232 are located at the inflection point segment 212a and extended relative to the first recesses 232, which can reduce the arrangement area of ​​the first recesses 232 and reduce the impact of the first recesses 232 on the energy density of the battery cell 11.

[0100] like Figure 5 and Figure 12 As shown, in some optional embodiments, both the anode sheet 240 and the cathode sheet 250 include a current collector 220 and active material layers 230 disposed on both sides of the current collector 220 in the thickness direction M. The anode sheet 240 is wound to form a first concave surface 241 and a first convex surface 242 located in the bending section 212. The first recess 232 is located on at least one of the first convex surface 242 and the first concave surface 241.

[0101] For example, the first recess 232 may be located on the first concave surface 241, or the first recess 232 may be located on the first convex surface 242, or both the first concave surface 241 and the first convex surface 242 may be provided with the first recess 232.

[0102] In these optional embodiments, the bent section 212 of the anode sheet 240 is curved, forming a first concave surface 241 and a first convex surface 242 disposed opposite to each other. The first recess 232 is located on at least one of the first convex surface 242 and the first concave surface 241. When the first recess 232 is disposed on the first convex surface 242, it is beneficial to increase the distance between the inflection point section 212a of the first convex surface 242 and the separator 300, thereby improving the wettability of the inflection point section 212a and reducing the risk of lithium plating. When the first recess 232 is disposed on the first concave surface 241, it increases the distance between the inflection point section 212a of the first concave surface 241 and the separator 300, thereby improving the wettability of the inflection point section 212a and reducing the risk of lithium plating.

[0103] like Figure 5 and Figure 12 As shown, in some alternative embodiments, the cathode sheet 250 is wound to form a second concave surface 251 and a second convex surface 252 located in the bent section 212, and the first recess 232 is located in at least one of the second convex surface 252 and the second concave surface 251.

[0104] For example, the first recess 232 may be located on the second concave surface 251, or the first recess 232 may be located on the second convex surface 252, or both the second concave surface 251 and the second convex surface 252 may be provided with the first recess 232.

[0105] In these optional embodiments, the bent section 212 of the cathode sheet 250 is curved, forming a second concave surface 251 and a second convex surface 252 disposed opposite to each other. A first recess 232 is located on at least one of the second convex surface 252 and the second concave surface 251. When the first recess 232 is disposed on the second convex surface 252, and the second convex surface 252 is adjacent to the first concave surface 241, the first recess 232 on the second convex surface 252 can reduce the mass of the active material at the inflection point segment 212a of the second convex surface 252, improving the lithium plating problem of the first concave surface 241. When the first recess 232 is disposed on the second concave surface 251, and the second concave surface 251 is adjacent to the first convex surface 242, the first recess 232 on the second concave surface 251 can reduce the mass of the active material at the inflection point segment 212a of the second concave surface 251, improving the lithium plating problem of the first convex surface 242.

[0106] like Figure 7 As shown, in some optional embodiments, the thickness difference K between the first recess 232 and the first main body 231 is 1 micrometer to 30 micrometers.

[0107] In these optional embodiments, the thickness difference K between the first recess 232 and the first main body 231 is 1 micrometer, 2 micrometer, 3 micrometer, 5 micrometer, 10 micrometer, 15 micrometer, 20 micrometer, 25 micrometer, 30 micrometer, etc., which improves the lithium plating problem while reducing the impact of the first recess 232 on the energy density of the battery cell 11.

[0108] like Figure 13 and Figure 14 As shown, in some optional embodiments, the active material layer 230 includes a second body portion 233 and a protrusion 234, the thickness of the protrusion 234 being greater than the thickness of the second body portion 233, and at least two protrusions 234 being located on both sides of the inflection point segment 212a in the length direction N of the electrode 210.

[0109] In these optional embodiments, at least two protrusions 234 are located on both sides of the inflection point segment 212a along the length direction N of the electrode 210. The thickness of the protrusions 234 is greater than the thickness of the second main body portion 233, that is, the distance between the protrusions 234 and the separator 300 is smaller. When the active material layer 230 expands, the protrusions 234 will contact the separator 300 first compared to the inflection point segment 212a, reducing the tendency of the active material layer 230 of the inflection point segment 212a to continue expanding, maintaining the distance between the active material layer 230 of the inflection point segment 212a and the separator 300, and improving the wettability of the electrode 210.

[0110] Optionally, the protrusion 234 disposed on the anode plate 240 can increase the mass of the active material layer 230 of the anode plate 240 and reduce the risk of lithium plating of the anode plate 240.

[0111] like Figure 13 and Figure 14 As shown, in some optional embodiments, the protrusion 234 is located in the middle of the electrode 210 along the third direction Z, where the first direction X, the second direction Y and the third direction Z intersect each other.

[0112] In these optional embodiments, the third direction Z is perpendicular to the length direction N of the electrode 210. The middle part of the inflection point segment 212a along the third direction Z has a relatively high concentration of lithium ions, resulting in a higher risk of lithium plating. The protrusion 234 is located in the middle of the electrode 210 along the third direction Z, thereby improving the lithium plating problem. When the protrusion 234 is located on the anode sheet 240, it can improve the quality of the active material layer 230 on both sides of the inflection point segment 212a, improving the lithium plating problem of the anode sheet 240. Furthermore, it can increase the distance between the anode sheet 240 and the separator 300. The protrusion 234 preferentially contacts the separator 300 compared to the inflection point segment 212a, reducing the tendency for the active material layer 230 of the inflection point segment 212a to continue expanding, maintaining the distance between the active material layer 230 and the separator 300, improving the wettability between the anode sheet 240 and the electrolyte, and further improving the lithium plating problem of the anode sheet 240.

[0113] like Figure 15 As shown, in some alternative embodiments, the protrusion 234 is disposed through the electrode 210 along the third direction Z.

[0114] In these alternative embodiments, the inflection point segment 212a extends along the third direction Z, and the protrusion 234 is located on both sides of the inflection point segment 212a along the length direction N of the electrode 210 and is disposed through the electrode 210 along the third direction Z, thereby improving the effect of improving the lithium plating problem of the inflection point segment 212a.

[0115] like Figure 13 As shown, in some alternative embodiments, the protrusion 234 extends through the electrode 210 along the length direction N of the electrode 210.

[0116] In these optional embodiments, the electrode 210 is wound along its length direction N to form a straight section 211 and a bent section 212, and the protrusion 234 penetrates the electrode 210 along its length direction N, such that the protrusion 234 passes through each inflection point section 212a. Providing a protrusion 234 that penetrates the length direction N of the electrode 210 helps to simplify the manufacturing process and improve the manufacturing efficiency of the battery cell 11.

[0117] like Figure 13 , Figure 15 and Figure 16 As shown, in some optional embodiments, the electrode 210 includes a plurality of protrusions 234, at least some of which are located on both sides of the inflection point segment 212a in the length direction N of the electrode 210.

[0118] For example, such as Figure 16As shown, the multiple protrusions 234 can be arranged along the length direction N of the electrode 210, and some of the protrusions 234 are located at the inflection point segment 212a.

[0119] For example, such as Figure 13 As shown, the multiple protrusions 234 can be arranged along the length direction N of the electrode 210, with some protrusions 234 located in the inflection point segment 212a, some protrusions 234 located in the transition segment 212b, and some protrusions 234 located in the straight segment 211.

[0120] For example, such as Figure 15 As shown, at least some of the protrusions 234 are located on both sides of the inflection point segment 212a in the length direction N of the electrode 210, which means that each protrusion 234 is located on both sides of the inflection point segment 212a in the length direction N of the electrode 210.

[0121] In these alternative embodiments, the electrode 210 is provided with a plurality of protrusions 234, and at least some of the protrusions 234 are located on both sides of the inflection point segment 212a extending relative to the protrusions 234 in the length direction N of the electrode 210, which can reduce the arrangement area of ​​the protrusions 234 and reduce the impact of the protrusions 234 on the energy density of the battery cell 11.

[0122] like Figures 13 to 16 As shown, in some optional embodiments, the second body portion 233 includes a first segment 233a and a second segment 233b, the second segment 233b being located between two adjacent protrusions 234, and at least a portion of the second segment 233b being located at the inflection point segment 212a, the first segment 233a being located on the side of the protrusion 234 away from the second segment 233b, and the thickness of the second segment 233b being less than the thickness of the protrusion 234.

[0123] For example, such as Figure 13 As shown, when the protrusion 234 is located in the middle of the electrode 210 along the third direction Z, the second segment 233b can be located in the inflection segment 212a and in the middle of the third direction Z of the inflection segment 212a.

[0124] For example, such as Figure 15 As shown, the protrusion 234 is disposed through the electrode 210 along the third direction Z and is located on both sides of the inflection point segment 212a along the length direction N of the electrode 210. The second segment 233b may be located in the inflection point segment 212a and penetrate the electrode 210 along the third direction Z.

[0125] For example, such as Figure 16 As shown, the protrusion 234 penetrates the electrode 210 along the length direction N of the electrode 210, and the second segment 233b extends along the length direction N of the electrode 210, with part of the second segment 233b located at the inflection point segment 212a.

[0126] In these alternative embodiments, the second segment 233b is located between two adjacent protrusions 234, and the thickness of the second segment 233b is less than the thickness of the protrusions 234, thereby increasing the spacing between the second segment 233b and the separator 300, improving the wettability of the second segment 233b, and improving the lithium plating problem of the inflection point segment 212a.

[0127] Optional, such as Figure 17 As shown, the thickness of the second segment 233b is less than that of the first segment 233a, thereby further increasing the distance between the second segment 233b and the protrusion 234, further increasing the distance between the second segment 233b and the separator 300, improving the wettability of the second segment 233b, and improving the lithium plating problem of the inflection point segment 212a.

[0128] like Figure 18 As shown, in some optional embodiments, the electrode 210 includes an anode sheet 240, which includes a current collector 220 and active material layers 230 disposed on both sides of the current collector 220 in the thickness direction M. The anode sheet 240 is wound to form a first concave surface 241 and a first convex surface 242 located in the bending section 212. The second main body portion 233 and the convex portion 234 are located on at least one of the first convex surface 242 and the first concave surface 241.

[0129] For example, the second main body portion 233 and the convex portion 234 may be located on the first concave surface 241, or the second main body portion 233 and the convex portion 234 may be located on the first convex surface 242, or both the first concave surface 241 and the first convex surface 242 may be provided with the second main body portion 233 and the convex portion 234.

[0130] In these optional embodiments, the bent section 212 of the anode sheet 240 is curved, forming a first concave surface 241 and a first convex surface 242 disposed opposite to each other. The second main body portion 233 and the convex portion 234 are located on at least one of the first convex surface 242 and the first concave surface 241. When the second main body portion 233 and the convex portion 234 are disposed on the first convex surface 242, the distance between the active material layer 230 of the first convex surface 242 and the separator 300 is increased, improving the wettability of the active material layer 230 and reducing the risk of lithium plating. When the convex portion 234 is disposed on the first concave surface 241, the distance between the active material layer 230 of the first concave surface 241 and the separator 300 is increased, improving the wettability of the active material layer 230 and reducing the risk of lithium plating.

[0131] Secondly, this application provides a battery device 10, including the battery cell 11 in any of the embodiments of the first aspect described above.

[0132] The battery device 10 provided in the embodiments of this application has all the beneficial effects of the battery cell 11 in any of the embodiments of the first aspect due to the use of the battery cell 11 provided in the first aspect. For details, please refer to the specific description of the battery cell 11 in the above embodiments. This embodiment will not repeat the description here.

[0133] Thirdly, this application also provides an electrical device, including the battery device 10 in any of the embodiments of the second aspect above, the battery device 10 being used to store or provide electrical energy.

[0134] In some optional embodiments, the battery cell 11 includes: a housing 100 and an electrode assembly 200, the electrode assembly 200 being disposed within the housing 100, the electrode assembly 200 including an electrode sheet 210, the electrode sheet 210 being wound to form a straight section 211 and bent sections 212 located on both sides of the straight section 211 along a first direction X, the bent sections 212 including an inflection point section 212a and transition sections 212b on both sides of the inflection point section 212a along a second direction Y, the transition sections 212b connecting the straight section 211 and the inflection point section 212a; the electrode sheet 210 includes an anode sheet 240 and a cathode sheet 250, the anode sheet 240 and Each cathode sheet 250 includes a current collector 220 and active material layers 230 disposed on both sides of the current collector 220 in the thickness direction M. An anode sheet 240 is wound to form a first concave surface 241 and a first convex surface 242 located in a bending section 212. The cathode sheet 250 is wound to form a second concave surface 251 and a second convex surface 252 located in the bending section 212. The active material layer 230 includes a first recess 232 located on the first convex surface 242 and the second concave surface 251. The first recess 232 penetrates the electrode sheet 210 along the length direction N, such that a portion of the first recess 232 is located at the inflection point section 212a. Alternatively, the active material layer 230 includes a second main body portion 233 and a convex portion 234, the thickness of which is greater than the thickness of the second main body portion 233. At least two convex portions 234 are located on both sides of the inflection point section 212a in the length direction N of the electrode sheet 210. The protrusion 234 is located on the first convex surface 242 and the first concave surface 241, and the protrusion 234 penetrates the electrode 210 along the length direction N of the electrode 210.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The application relates to a battery, comprising: a shell; an electrode assembly arranged in the shell, the electrode assembly comprising a tab, the tab being wound to form a flat section and a bending section located on both sides of the flat section in a first direction, the bending section comprising a turning point section and a transition section located on both sides of the turning point section in a second direction, the transition section connecting between the flat section and the turning point section; the tab comprising a current collector and an active material layer arranged on at least one side of the current collector in a thickness direction, the thickness of at least part of the active material layer located at the turning point section being smaller than the thickness of at least part of the active material layer located at the transition section, the first direction and the second direction being arranged to intersect.

2. The battery cell of claim 1, wherein, the active material layer comprising a first main part and a first recess, the thickness of the first recess being smaller than the thickness of the main part, and at least part of the first recess being located at the turning point section.

3. The battery cell of claim 2, wherein, the first recess being located at the middle of the tab in a third direction, and the first main part being located on both sides of the first recess in the third direction; or, the first recess being arranged to penetrate the tab in the third direction; the first direction, the second direction and the third direction intersecting each other in pairs.

4. The battery cell of claim 2, wherein, the first recess penetrating the tab in a length direction of the tab, or the tab comprising a plurality of the first recesses, at least part of the first recesses being located at the turning point section.

5. The battery cell of claim 2, wherein, the tab comprising an anode tab and a cathode tab, the anode tab and the cathode tab both comprising the current collector and the active material layer arranged on both sides of the current collector in the thickness direction, the anode tab being wound to form a first concave surface and a first convex surface located at the bending section, and the first recess being located at at least one of the first convex surface and the first concave surface; and / or, the cathode tab being wound to form a second concave surface and a second convex surface located at the bending section, and the first recess being located at at least one of the second convex surface and the second concave surface.

6. The battery cell of any one of claims 2-5, wherein, the thickness difference between the first recess and the first main part being 1-30 microns.

7. The battery cell of claim 1, wherein, the active material layer comprising a second main part and a protrusion, the thickness of the protrusion being greater than the thickness of the second main part, and at least two protrusions being located on both sides of the turning point section in the length direction of the tab.

8. The battery cell of claim 7, wherein, the protrusion being located at the middle of the tab in a third direction, or the protrusion being arranged to penetrate the tab in the third direction; the first direction, the second direction and the third direction intersecting each other in pairs.

9. The battery cell of claim 7, wherein, the protrusion penetrating the tab in a length direction of the tab, or the tab comprising a plurality of the protrusions, at least part of the protrusions being located on both sides of the turning point section in the length direction of the tab.

10. The battery cell of claim 7, wherein, the second main part comprising a first subsection and a second subsection, the second subsection being located between adjacent two protrusions, and at least part of the second subsection being located at the turning point section, the first subsection being located on a side of the protrusion away from the second subsection, the thickness of the second subsection being smaller than the thickness of the protrusion, or the thickness of the second subsection being smaller than the thickness of the first subsection.

11. The battery cell of any one of claims 7-10, wherein, The electrode sheet includes an anode sheet including the current collector and the active material layer provided on both sides in the thickness direction of the current collector, and the anode sheet is wound to form a first convex surface and a first concave surface of the bent section, and the second main body portion and the protruding portion are located at at least one of the first convex surface and the first concave surface.

12. A battery device characterized by comprising: A battery including the battery cell of any one of claims 1-11.

13. An electrical device, comprising: A battery device including the battery cell of claim 12.

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