Battery monomer, pole piece, rolling device, battery device and power utilization device

Abstract

The utility model discloses a battery monomer, a pole piece, a rolling device, a battery device and a power utilization device. The battery monomer comprises a shell, a top cover assembly and an electrode assembly, the shell is provided with an opening; the top cover assembly covers the opening; the electrode assembly is located in the shell, the electrode assembly comprises a pole piece, and the pole piece comprises a current collecting part and an active material layer which are arranged in a stacked mode; the active material layer is arranged on at least one side of the current collecting part; wherein a concave part is formed in one side, deviating from the current collecting part, of the active material layer, so that the liquid retaining capability of the active material layer on electrode liquid is improved, and the performance 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, electrode, rolling device, battery device, and power-consuming 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 performance of individual battery cells are becoming increasingly stringent. However, the performance of current individual battery cells is relatively poor and still needs further improvement. Utility Model Content

[0004] This application provides a battery cell, electrode, rolling device, battery assembly, and power supply device, which can improve the electrical performance of the battery cell.

[0005] In a first aspect, this application provides a battery cell, including: a housing, a top cover assembly, and an electrode assembly; the housing has an opening; the top cover assembly closes to the opening; the electrode assembly is located inside the housing, the electrode assembly includes an electrode sheet, the electrode sheet includes a current collector and an active material layer stacked together; the active material layer is disposed on at least one side of the current collector; wherein, the side of the active material layer opposite to the current collector has a recess.

[0006] In this embodiment, the active material layer is coated on at least one side of the current collector, and a recess is provided on the side of the active material layer away from the current collector. During the charging and discharging process of the battery cell, the active material layer reacts with the electrolyte. Providing a recess on the side of the active material layer away from the current collector can increase the contact area between the active material layer and the electrolyte, improve the liquid retention capacity of the active material layer for the electrode liquid, and thus improve the performance of the battery cell.

[0007] According to the embodiments of this application, the active material layer has multiple recesses on the side opposite to the current collector. The multiple recesses are spaced apart and arranged in an array, which can increase the density of the recesses on the surface of the active material layer and improve the electrolyte retention capacity.

[0008] According to the embodiments of this application, the active material layer and the flow collection part are stacked, and at least some of the recesses are projected as polygons or circles in the thickness direction of the active material layer, and / or, the inner surface of at least some of the recesses is part of a sphere, pyramid, cone or prism, thereby adjusting the liquid retention capacity of the active material layer.

[0009] According to embodiments of this application, at least some of the recesses are projected as rectangles in the thickness direction of the active material layer, and the dimensions of the recesses along the first direction are 10 mm to 50 mm; and / or, the dimensions of the recesses along the second direction are 10 mm to 50 mm, so that the liquid retention capacity of the active material layer can be adjusted according to the dimensions of the recesses in the first and second directions.

[0010] According to embodiments of this application, at least some of the recesses project circularly along the thickness direction of the active material layer, and the radius of the projection of the recesses along the thickness direction is 10 mm to 50 mm. The liquid retention capacity of the active material layer can be adjusted according to the radius of the projection of the recesses along the thickness direction.

[0011] According to the embodiments of this application, the depth of the recess is 10 micrometers to 50 micrometers, and the specific depth can be adaptively selected according to the size of different active material layers and the liquid retention effect.

[0012] According to embodiments of this application, the center-to-center distance between two adjacent recesses is between 5 mm and 100 mm. By setting different center-to-center distances, the density of the recesses on the active material layer can be adjusted, thereby regulating the liquid retention capacity of the active material layer.

[0013] Secondly, this application provides an electrode sheet applied to a battery cell in any of the embodiments of the first aspect above. The electrode sheet includes a current collector and an active material layer stacked together; a recess is provided on the side of the active material layer opposite to the current collector.

[0014] In this embodiment, providing a recess on the side of the active material layer away from the current collector can increase the contact area between the active material layer and the electrolyte, improve the liquid retention capacity of the active material layer for the electrode liquid, and thus improve the performance of the battery cell.

[0015] Thirdly, this application provides a rolling device for processing battery cells in any of the first aspects or electrode sheets in the second aspects. The rolling device includes two embossing rollers spaced apart. At least a portion of the outer peripheral surface of at least one embossing roller is provided with a protrusion. There is a gap between the two embossing rollers for the electrode sheet to pass through. The protrusion is used to form a concave portion on the side of the active material layer away from the current collector. The distance between the side of the protrusion away from the embossing roller and the embossing roller is less than or equal to the thickness of the active material layer.

[0016] In this embodiment, when the electrode passes through the gap between the two embossing rollers, the protrusions on the embossing rollers can form concave portions in the electrode thickness direction. The distance between the side of the protrusion away from the embossing roller and the embossing roller is less than or equal to the thickness of the active material layer, thereby allowing the concave portion to exist in the active material layer, reducing the probability of the current collection section being exposed by the concave portion, and thus improving the liquid retention capacity of the active material layer.

[0017] Fourthly, this application provides a battery device including a battery cell according to any embodiment of the first aspect.

[0018] Fifthly, this application provides an electrical device, including the battery device in the fourth aspect embodiment. Attached Figure Description

[0019] 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:

[0020] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0021] Figure 2 Exploded view of the battery device according to some embodiments of this application;

[0022] Figure 3 This is a schematic diagram of the structure of a battery module according to some embodiments of this application;

[0023] Figure 4 This is a schematic diagram of the exploded structure of a battery cell according to some embodiments of this application;

[0024] Figure 5 This is a schematic diagram of the structure of the electrode sheet in some embodiments of this application;

[0025] Figure 6 yes Figure 5 Cross-sectional view at point AA;

[0026] Figure 7 This is a schematic diagram of the structure of the electrode sheet in some other embodiments of this application;

[0027] Figure 8 This is a cross-sectional schematic diagram of the electrode sheet in some other embodiments of this application;

[0028] Figure 9 This is a schematic diagram of the structure of the electrode sheet in some embodiments of this application;

[0029] Figure 10 This is a cross-sectional schematic diagram of the electrode sheet in some embodiments of this application.

[0030] Figure label:

[0031] 1. Vehicles;

[0032] 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;

[0033] 100. Housing; 101. Opening; 110. Top cover assembly; 200. Electrode assembly; 210. Electrode sheet; 211. Current collector; 212. Active material layer; 300. Recess;

[0034] 400, embossing roller; 410, convex part;

[0035] X, first direction; Y, second direction; Z, depth direction. Detailed Implementation

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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).

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] A single battery cell includes electrode components and an electrolyte. The electrode components include a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrode components. The positive electrode includes a positive current collector and a positive active material layer, the latter coated on the surface of the current collector. The current collector includes a positive current-collecting section and a positive electrode tab connected to it. The current-collecting section is coated with the positive active material layer, while the tab is not. Taking a lithium-ion battery as an example, the positive current collector can be made of aluminum, and the positive active material layer includes the positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet includes a negative current collector and a negative active material layer, the negative active material layer being coated on the surface of the negative current collector. The negative current collector includes a negative current collection section and a negative electrode tab connected to the negative current collection section. The negative current collection section is coated with the negative active material layer, while the negative electrode tab is not coated with the negative active material layer. The material of the negative current collector can be copper, and the negative active material layer includes a negative active material, which can be carbon or silicon, etc.

[0048] 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 positive and negative active material layers react with the electrolyte, and the tabs connect 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. The formed internal environment can accommodate the electrode assemblies, electrolyte, and other components. The housing and top cover assembly can be independent components. An opening can be provided on the housing, and the top cover assembly closes the opening to form the internal environment of the battery cell. Optionally, the top cover assembly and housing can be integrated. Optionally, the top cover assembly and 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.

[0049] In related technologies, the 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.

[0050] To address the aforementioned technical problems, this application provides a technical solution whereby the electrode includes a current collector and an active material layer stacked together; the active material layer is disposed on at least one side of the current collector; wherein, a recess is provided on the side of the active material layer facing away from the current collector. The recess can increase the contact area between the active material layer and the electrolyte, thereby improving the electrolyte retention capacity of the active material layer and thus enhancing the performance of the battery cell.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0056] 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.

[0057] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0058] 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.

[0059] 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.

[0060] Please see Figure 1 , Figure 1This is a schematic diagram of the structure of a vehicle provided in an embodiment of this application.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] Figure 3 This is a schematic diagram of the structure of a battery module provided in an embodiment of this application.

[0066] In some embodiments, such as Figure 3 As 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.

[0067] like Figures 4 to 6 As shown, this application provides a battery cell 11, including: a housing 100, a top cover assembly 110, and an electrode assembly 200; the housing 100 is provided with an opening 101; the top cover assembly 110 covers the opening 101; the electrode assembly 200 is located inside the housing 100, and the electrode assembly 200 includes an electrode sheet 210, the electrode sheet 210 including a current collector 211 and an active material layer 212 stacked thereon; the active material layer 212 is disposed on at least one side of the current collector 211; wherein, the side of the active material layer 212 facing away from the current collector 211 is provided with a recess 300.

[0068] For example, the active material layer 212 is disposed on one side of the current collection section 211 in the thickness direction, or the active material layer 212 is disposed on both sides of the current collection section 211 in the thickness direction.

[0069] For example, the active material layer 212 has a recess 300 on the side opposite to the current collection section 211, which can be one or more.

[0070] For example, the active material layer 212 is provided with a plurality of recesses 300, which are either arranged continuously or spaced apart from each other.

[0071] For example, the active material layer 212 is provided with a plurality of recesses 300, and the projections of each recess 300 in the thickness direction of the active material layer 212 are the same or at least partially different.

[0072] For example, electrode 210 can be an anode plate 210 or a cathode plate 210.

[0073] In this embodiment, the battery cell 11 includes a housing 100, a top cover assembly 110, and an electrode assembly 200. The housing 100 includes an opening 101, and the top cover assembly 110 covers the opening 101. The electrode assembly 200 is located inside the housing 100 and performs electrochemical reactions. An active material layer 212 is coated on at least one side of the current collector 211. A recess 300 is provided on the side of the active material layer 212 away from the current collector 211. During the charging and discharging process of the battery cell 11, the active material layer 212 reacts with the electrolyte. Providing a recess 300 on the side of the active material layer 212 away from the current collector 211 can increase the contact area between the active material layer 212 and the electrolyte, improve the electrolyte retention capacity of the active material layer 212, and thus improve the reliability and electrical performance of the battery cell 11.

[0074] like Figure 5 and Figure 6 As shown, in some optional embodiments, the active material layer 212 has a plurality of recesses 300 on the side opposite to the current collection section 211, and the plurality of recesses 300 are spaced apart and arranged in an array.

[0075] For example, the spacing between two adjacent recesses 300 may be the same or different.

[0076] For example, a plurality of recesses 300 are arranged in an array along a first direction X and / or a second direction Y, the first direction X and the second direction Y intersect each other, and both the first direction X and the second direction Y are perpendicular to the thickness direction of the active material layer 212. Optionally, the first direction X, the second direction Y and the thickness direction of the active material layer 212 are mutually perpendicular.

[0077] In these optional embodiments, the active material layer 212 is provided with a plurality of recesses 300 to improve the electrolyte retention capacity of the active material layer 212, and the multiple recesses 300 are spaced apart to reduce the impact of the recesses 300 on the structural strength of the active material layer 212.

[0078] like Figures 5 to 8 As shown, in some optional embodiments, the active material layer 212 and the current collection portion 211 are stacked, and at least some of the recesses 300 are projected as polygons or circles in the thickness direction of the active material layer 212.

[0079] In these optional embodiments, the shapes of the projections of at least some of the recesses 300 onto the thickness direction of the active material layer 212 can be the same or different. The polygons can have equal or unequal side lengths and can include quadrilaterals, pentagons, hexagons, etc. When the projection of the recess 300 onto the thickness direction of the active material is a polygon, the recess 300 can be a quadrangular prism-shaped recess, a quadrangular pyramid-shaped recess, a pentagonal prism-shaped recess, a pentagonal pyramid-shaped recess, a hexagonal prism-shaped recess, a hexagonal pyramid-shaped recess, etc. When the projection of the recess 300 onto the thickness direction of the active material layer 212 is circular, the recess 300 can be a cylindrical recess, a conical recess, or a frustum-shaped recess, etc.

[0080] like Figures 7 to 10 As shown, in some alternative embodiments, at least a portion of the inner surface of the recess 300 is part of a sphere, pyramid, cone, or prism.

[0081] In these alternative embodiments, the inner surfaces of at least some of the recesses 300 may be the same or different. The inner surface of the recess 300 is part of a sphere, such as... Figure 7 and Figure 8As shown, the recess 300 can be a hemispherical groove, etc. The inner surface of the recess 300 is part of a pyramid, that is, the recess 300 can be a frustum-shaped groove, etc. For example... Figure 9 and Figure 10 As shown, the inner surface of the recess 300 is part of a cone, that is, the recess 300 can be a frustum-shaped groove, etc. The inner surface of the recess 300 is part of a prism, and the recess 300 can be a square prism-shaped groove, a pentagonal prism-shaped groove, or a hexagonal prism-shaped groove, etc.

[0082] like Figure 5 As shown, in some optional embodiments, at least some of the recesses 300 are projected as rectangles in the thickness direction of the active material layer 212, and the dimensions of the recesses 300 along the first direction X are 10 mm to 50 mm; and / or, the dimensions of the recesses 300 along the second direction Y are 10 mm to 50 mm.

[0083] For example, at least some of the recesses 300 are projected as rectangles in the thickness direction of the active material layer 212, and the recesses 300 can be cuboid grooves or cube grooves.

[0084] In these optional embodiments, the dimension of the recess 300 along the first direction X can be from 10 mm to 50 mm, specifically 10 mm, 15 mm, 20 mm, 30 mm, 40 mm, or 50 mm. The dimension of the recess 300 along the second direction Y can be from 10 mm to 50 mm, specifically 10 mm, 15 mm, 20 mm, 30 mm, 40 mm, or 50 mm, etc., and the dimension of the recess 300 can be selected according to the different dimensions of the active material layer 212 and the liquid retention effect.

[0085] like Figure 7 As shown, in some optional embodiments, at least some of the recesses 300 are projected in the thickness direction of the active material layer 212 as circles, and the radius of the projection of the recesses 300 in the thickness direction is 10 mm to 50 mm.

[0086] In these optional embodiments, when the projection of the recess 300 in the thickness direction of the active material layer 212 is circular, the recess 300 can be a cylindrical recess, a conical recess, or a frustum-shaped recess, etc. The radius of the projection of the recess 300 in the thickness direction is 10 to 50 millimeters, specifically 10 millimeters, 15 millimeters, 20 millimeters, 30 millimeters, 40 millimeters, or 50 millimeters, etc. When the recess 300 is a conical recess or a frustum-shaped recess, the diameter of the recess 300 facing the collection portion 211 is larger than the diameter of the recess 300 away from the collection portion 211, thereby improving the liquid retention capacity of the active material layer 212.

[0087] In some alternative embodiments, the depth of the recess 300 is 10 micrometers to 50 micrometers.

[0088] In these alternative embodiments, the depth direction Z of the recess 300 is perpendicular to the first direction X and the second direction Y. The depth of the recess 300 is from 10 micrometers to 50 micrometers, specifically 10 millimeters, 15 millimeters, 20 millimeters, 30 millimeters, 40 millimeters, or 50 millimeters, etc.

[0089] Optional, such as Figure 5 and Figure 6 As shown, the depth direction Z, the first direction X, and the second direction Y of the recess 300 are mutually perpendicular.

[0090] In some alternative embodiments, the center distance between two adjacent recesses 300 is between 5 mm and 100 mm.

[0091] In these optional embodiments, the center distance between two adjacent recesses 300 is between 5 mm and 100 mm, specifically 5 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 80 mm or 100 mm, etc. By setting different center distances, the density of the recesses 300 on the active material layer 212 can be adjusted, thereby adjusting the liquid retention capacity of the active material layer 212.

[0092] In some optional embodiments, the battery cell 11 includes: a housing 100, a top cover assembly 110, and an electrode assembly 200; the housing 100 has an opening 101; the top cover assembly 110 covers the opening 101; the electrode assembly 200 is located inside the housing 100, and the electrode assembly 200 includes an electrode sheet 210, which includes a current collector 211 and an active material layer 212 stacked together; the active material layer 212 is disposed on at least one side of the current collector 211; wherein, the side of the active material layer 212 opposite to the current collector 211 is provided with a plurality of spaced recesses 300, and the plurality of recesses 300 are spaced apart along a first direction X and a second direction Y and arranged in an array. The projection of the recesses 300 in the thickness direction of the active material layer 212 is rectangular or circular, or the inner surface of the recesses 300 is spherical or frustum-shaped.

[0093] Secondly, this application provides an electrode 210, which is applied to the battery cell 11 in any of the embodiments of the first aspect above. The electrode 210 includes a current collector 211 and an active material layer 212 stacked together. A recess 300 is provided on the side of the active material layer 212 away from the current collector 211.

[0094] In this embodiment, the active material layer 212 is coated on at least one side of the current collector 211. A recess 300 is provided on the side of the active material layer 212 away from the current collector 211. During the charging and discharging process of the battery cell 11, the active material layer 212 reacts with the electrolyte. Providing a recess 300 on the side of the active material layer 212 away from the current collector 211 can increase the contact area between the active material layer 212 and the electrolyte, improve the electrolyte retention capacity of the active material layer 212, and thus improve the performance of the battery cell 11.

[0095] Thirdly, this application provides a rolling device for processing the battery cell 11 of any embodiment of the first aspect or the electrode 210 of any embodiment of the second aspect. The rolling device includes two embossing rollers 400 spaced apart, with a gap between the two embossing rollers 400 for the electrode 210 to pass through. At least a portion of the outer peripheral surface of at least one embossing roller 400 is provided with a protrusion 410, which is used to form a recess 300 on the side of the active material layer 212 away from the current collector 211. The distance between the side of the protrusion 410 away from the embossing roller 400 and the embossing roller 400 is less than or equal to the thickness of the active material layer 212.

[0096] For example, there may be one or more protrusions 410.

[0097] For example, the embossing roller 400 is provided with a plurality of protrusions 410, which are arranged continuously or spaced apart from each other.

[0098] For example, the shapes of the protrusions 410 may be the same or at least partially different.

[0099] In this embodiment, when the electrode 210 passes through the gap between the two embossing rollers 400, the protrusion 410 on the embossing roller 400 can form a recess 300 in the thickness direction of the electrode 210. The distance between the side of the protrusion 410 away from the embossing roller 400 and the embossing roller 400 is less than or equal to the thickness of the active material layer 212, so that the recess 300 exists in the active material layer 212, reducing the probability of the current collection section 211 being exposed by the recess 300, thereby improving the liquid retention capacity of the active material layer 212.

[0100] Fourthly, this application provides a battery device 10, including the battery cell 11 in any of the embodiments of the first aspect described above.

[0101] 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.

[0102] Fifthly, this application also provides an electrical device, including the battery device 10 in any of the embodiments of the fourth aspect above, the battery device 10 being used to store or provide electrical energy.

[0103] 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 battery cell comprises: a housing provided with an opening; a top cover assembly covering the opening; an electrode assembly located in the housing, the electrode assembly comprising a tab, the tab comprising a current collector and an active material layer stacked together; the active material layer is provided on at least one side of the current collector; wherein the side of the active material layer away from the current collector is provided with a recess.

2. The battery cell of claim 1, wherein, The side of the active material layer away from the current collector is provided with a plurality of recesses, and the plurality of recesses are arranged in an array.

3. The battery cell of claim 1, wherein, The active material layer and the current collector are stacked together, and the projection of at least part of the recesses in the thickness direction of the active material layer is a polygon or a circle, and / or the inner surface of at least part of the recesses is a part of a spherical, pyramid, conical or prismatic body.

4. The battery cell of claim 3, wherein, The projection of at least part of the recesses in the thickness direction of the active material layer is a rectangle, and the size of the recess in the first direction is 10-50 mm; and / or the size of the recess in the second direction is 10-50 mm.

5. The battery cell of claim 3, wherein, The projection of at least part of the recesses in the thickness direction of the active material layer is a circle, and the radius of the projection of the recess in the thickness direction is 10-50 mm.

6. The battery cell of any one of claims 1-5, wherein, The depth of the recess is 10-50 microns.

7. The battery cell of any one of claims 1-6, wherein, The center distance between two adjacent recesses is 5-100 mm.

8. A pole piece for use in a battery cell as claimed in any one of claims 1 to 7, characterized in that The tab comprises a current collector and an active material layer stacked together; the side of the active material layer away from the current collector is provided with a recess.

9. A roller press device characterized by comprising: The roller device for processing the battery cell of any one of claims 1-7 or the tab of claim 8 comprises two embossing rollers arranged at intervals, at least part of the outer surface of at least one of the embossing rollers is provided with a protrusion, and there is a gap between the two embossing rollers for the tab to pass through, the protrusion is used to form a recess on the side of the active material layer away from the current collector; The distance between the side of the protrusion away from the embossing roller and the embossing roller is less than or equal to the thickness of the active material layer.

10. A battery device characterized by comprising: The battery cell of any one of claims 1-7.

11. An electrical device, characterized by The battery device of claim 10.

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