Battery monomer, battery device and electric equipment

Abstract

The utility model discloses a battery monomer, a battery device and electric equipment, the battery monomer comprises a shell and an electrode assembly, the electrode assembly is arranged in the shell, and the electrode assembly comprises a positive pole piece, a separator and a negative pole piece which are stacked, a plurality of grooves are formed in at least one of the two surfaces, oppositely arranged in the thickness direction of the separator, of the separator, and the grooves are sunken in the thickness direction and are arranged at intervals. The battery monomer provided by the embodiment of the utility model can improve the cycle performance and improve the reliability.

Description

Technical Field

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

[0002] With the development of new energy technologies, batteries 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] The development of battery technology must take into account multiple design factors. For example, how to improve the cycle performance and lifespan of individual battery cells is an important research direction in the battery field. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical appliance that can improve cycle performance and extend service life.

[0005] In a first aspect, this application provides a battery cell, including a housing and an electrode assembly. The electrode assembly is disposed in the housing and includes a positive electrode sheet, a separator and a negative electrode sheet stacked together. At least one of the two surfaces of the separator disposed opposite to each other in its thickness direction has a plurality of grooves. The plurality of grooves are recessed along the thickness direction and are spaced apart from each other.

[0006] In the technical solution of this application embodiment, an electrode assembly is disposed within the casing of a battery cell. The electrode assembly further includes a positive electrode sheet, a separator, and a negative electrode sheet stacked together. The separator has a groove on at least one surface along its thickness. By providing a groove on the separator, space can be provided for the electrolyte, improving the separator's ability to retain and store the electrolyte, thereby improving the cycle performance of the battery cell. Simultaneously, the groove provides a certain gap between the separator and the electrode sheet, thereby improving the smoothness of venting of the electrode assembly during operation, and thus improving the reliability of the battery cell.

[0007] According to some embodiments of this application, the separator has grooves on both opposite sides in its thickness direction, and the grooves on opposite sides of the separator in the thickness direction are spaced apart from each other. Simultaneously providing grooves on both sides of the separator can further improve the reliability of the battery cell.

[0008] According to some embodiments of this application, the groove includes a first groove and a second groove respectively disposed on opposite sides of the separator, and the first groove and the second groove are symmetrically arranged in the thickness direction. This makes the overall structural strength of the separator more uniform and reduces the possibility of stress concentration leading to damage.

[0009] According to some embodiments of this application, in the thickness direction, the size of the separator is L1, and the sizes of the two grooves are L2 and L3 respectively; L2+L3<L1, 1μm≤L2+L3-0.5L1≤3μm. This ensures that the grooves have a suitable depth, reducing the possibility of the separator being too thin and thus cracking, and the possibility of the grooves being too shallow and thus resulting in an insignificant liquid retention effect.

[0010] According to some embodiments of this application, in the thickness direction, the size L1 of the spacer is 7μm-15μm, and the sizes L2 and L3 of the groove are both 2μm-5μm. The thickness of the spacer and the depth of the groove are further defined.

[0011] According to some embodiments of this application, the groove has an opening and a bottom wall opposite each other in the thickness direction. The area of ​​the opening is smaller than the area of ​​the bottom wall, and the orthographic projection of the opening lies within the outline of the orthographic projection of the bottom wall along the thickness direction. The groove has a structure with a small opening and a large bottom, which further improves the liquid holding capacity.

[0012] According to some embodiments of this application, both the opening and the bottom wall are rectangular, with the edge dimensions of the opening being 10mm-50mm and the edge dimensions of the bottom wall being 14mm-70mm. This makes the groove easy to process and has suitable dimensions.

[0013] According to some embodiments of this application, at least a portion of the groove includes a central groove and multiple sub-grooves, which are arranged sequentially along the circumference of the central groove, and the central groove is connected to each of the multiple sub-grooves. The interconnected central groove and multiple sub-grooves allow the electrolyte residing in the central groove to be dispersed into the sub-grooves, providing a continuous diffusion supply and further improving the liquid retention capacity.

[0014] According to some embodiments of this application, multiple sub-cells are arranged at equal intervals along the circumference of the central cell, and the areas of the multiple sub-cells are the same. This ensures uniform electrolyte diffusion efficiency in all directions and improves the uniformity of electrolyte wetting.

[0015] According to some embodiments of this application, the central groove is circular, elliptical, or polygonal, and the sub-grooves are rectangular, circular, elliptical, or polygonal. This facilitates the machining of the grooves and allows for easy communication between the central groove and the sub-grooves.

[0016] According to some embodiments of this application, the central groove and multiple sub-grooves are all circular, with the radius of the central groove being 10mm-60mm and the radius of the sub-grooves being 5mm-10mm. This ensures that the central groove and sub-grooves have suitable dimensions and areas.

[0017] According to some embodiments of this application, multiple grooves are arranged in an array on the surface of the separator. This ensures that the grooves are evenly distributed on the separator, further improving the uniformity of electrolyte wetting and retention.

[0018] According to some embodiments of this application, the spacer includes a substrate and a coating disposed on at least one of opposite surfaces of the substrate, with a groove disposed in the coating. This facilitates the molding of the groove and reduces the possibility of problems such as substrate breakage during folding of the spacer.

[0019] Secondly, according to the embodiments of this application, a battery device is provided, including a housing and a battery cell as described in any embodiment of the first aspect, wherein the battery cell is disposed in the housing.

[0020] Thirdly, according to the embodiments of this application, an electrical device is provided, including the battery device in any embodiment of the second aspect, the battery device being used to provide electrical energy. 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 A simplified schematic diagram of a vehicle provided for some embodiments of this application;

[0023] Figure 2 Explosion-proof diagrams of battery devices provided in some embodiments of this application;

[0024] Figure 3 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application;

[0025] Figure 4 A cross-sectional schematic diagram of an electrode assembly provided in some embodiments of this application;

[0026] Figure 5 This is a schematic diagram of the structure of the isolation element provided in some embodiments of this application;

[0027] Figure 6 for Figure 5 A schematic cross-sectional view at point A-A' shown;

[0028] Figure 7 for Figure 5 Another cross-sectional view of section A-A' shown;

[0029] Figure 8 This is a schematic diagram of the structure of the isolation element provided in some other embodiments of this application;

[0030] Figure 9 for Figure 8 A cross-sectional view at point B-B' is shown.

[0031] Figure label:

[0032] 1000 - Vehicles;

[0033] 100 - Individual battery cell; 200 - Battery assembly; 300 - Controller; 400 - Motor;

[0034] 10 - Housing; 20 - Electrode assembly; 30 - Box;

[0035] 21-Positive electrode plate; 22-Isolator; 23-Negative electrode plate; 31-First housing section; 32-Second housing section; 33-Receiving section;

[0036] 221 - Groove; 222 - First groove; 223 - Second groove; 224 - Opening; 225 - Bottom wall; 226 - Central groove; 227 - Sub-groove;

[0037] X - Thickness direction. Detailed Implementation

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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).

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0049] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0050] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0051] As an example, the positive current collector can be a metal foil or a composite current collector.

[0052] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0053] As an example, the negative electrode current collector can be made of metal foil, foam metal, or composite current collector.

[0054] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0055] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0056] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc.

[0057] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0058] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0059] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0060] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride, and ceramic.

[0061] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0062] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0063] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0064] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0065] In some embodiments, the housing may be provided with functional components such as electrode terminals. The electrode terminals can be used to electrically connect to the electrode assembly for outputting or inputting electrical energy into the battery cell.

[0066] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0067] The battery device mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0068] In some embodiments, the battery device can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0069] In some embodiments, the battery device may be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0070] 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.

[0071] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0072] A battery cell typically includes a casing and electrode assemblies and electrolyte disposed within the casing. The electrode assemblies typically include a positive electrode, a negative electrode, and a separator for forming an insulating structure between the two. During the operation of the battery cell, the electrode assemblies usually need to be immersed in the electrolyte, and the electrolyte needs to wet the separator to ensure that the battery cell has good cycle performance.

[0073] Based on this, the applicant found that existing separators are usually relatively flat structures and the electrodes and separators in the electrode assembly are usually tightly attached. After the separator is immersed in the electrolyte, the electrolyte is not easy to remain on the separator. It is difficult for the electrolyte to wet the middle area of ​​the separator. Furthermore, due to the large expansion force generated by the electrode assembly during cycling, the electrolyte is not easy to flow back to the middle of the electrode, resulting in poor cycling performance of the electrode assembly and low lifespan of the battery cell.

[0074] In view of this, the present application provides a technical solution that improves the retention capacity of the electrolyte in the separator by setting grooves on the separator, thereby improving the cycle performance and service life of the battery cell.

[0075] The technical solutions described in this application are applicable to battery devices and electrical equipment using battery devices. Electrical equipment includes, 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.

[0076] 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.

[0077] Please see Figure 1 , Figure 1This is a simplified schematic diagram of a vehicle provided in some embodiments of this application. The vehicle 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 200 can be installed inside the vehicle 1000; specifically, for example, the battery device 200 can be installed at the bottom, front, or rear of the vehicle 1000. The battery device 200 can be used to power the vehicle 1000; for example, the battery device 200 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 300 and a motor 400. The controller 300, for example, is used to control the battery to supply power to the motor 400. The battery device 200 can be used for starting the vehicle 1000, navigation, etc. Of course, the battery can also be used to drive the vehicle 1000, replacing or partially replacing gasoline or natural gas to provide propulsion for the vehicle 1000.

[0078] Figure 2 This is an exploded schematic diagram of a battery device provided in some embodiments of this application. For example... Figure 2 As shown, the battery device 200 includes a housing 30 and a battery cell 100, with the battery cell 100 housed within the housing 30.

[0079] The housing 30 is used to accommodate the battery cell 100, and the housing 30 can have various structures. In some embodiments, the housing 30 may include a first housing portion 31 and a second housing portion 32, which overlap each other, and together define a receiving portion 33 for accommodating the battery cell 100. The second housing portion 32 may be a hollow structure with an opening 224 at one end, and the first housing portion 31 may be a plate-like structure, covering the opening 224 side of the second housing portion 32 to form a housing 30 with the receiving portion 33; alternatively, both the first housing portion 31 and the second housing portion 32 may be hollow structures with an opening 224 on one side, with the opening 224 side of the first housing portion 31 covering the opening 224 side of the second housing portion 32 to form a housing 30 with the receiving portion 33. Of course, the first housing portion 31 and the second housing portion 32 can be various shapes, such as cylinders, cuboids, etc.

[0080] In a battery, there can be one or more battery cells 100. If there are multiple battery cells 100, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 100 are connected in both series and parallel. Multiple battery cells 100 can be directly connected in series, in parallel, or in a mixed configuration, and then the whole assembly of multiple battery cells 100 is housed in the housing 30. Alternatively, multiple battery cells 100 can first be connected in series, in parallel, or in a mixed configuration to form a battery module, and then multiple battery modules can be connected in series, in parallel, or in a mixed configuration to form a whole assembly, which is then housed in the housing 30.

[0081] In some embodiments, there are multiple battery cells 100, which are first connected in series, parallel, or mixed to form a battery module. The multiple battery modules are then connected in series, parallel, or mixed to form a whole and housed in the housing 30.

[0082] Next, we will combine the appendix Figure 3 To be continued Figure 9 The structure of the battery cell 100, the battery device 200, and the electrical equipment is described.

[0083] Please refer to the following: Figures 3 to 6 , Figure 3 This is an exploded view of a single battery cell provided in some embodiments of this application. Figure 4 This is a cross-sectional schematic diagram of an electrode assembly provided in some embodiments of this application. Figure 5 This is a schematic diagram of the structure of the isolation component provided in some embodiments of this application. Figure 6 for Figure 5 A cross-sectional view of section A-A' shown.

[0084] In a first aspect, this application provides a battery cell 100, including a housing 10 and an electrode assembly 20. The electrode assembly 20 is disposed in the housing 10 and includes a positive electrode 21, a separator 22 and a negative electrode 23 stacked together. At least one of the two surfaces of the separator 22 disposed opposite to each other in its own thickness direction X has a plurality of grooves 221. The plurality of grooves 221 are recessed along the thickness direction X and are spaced apart from each other.

[0085] This application provides a battery cell 100, including a housing 10 for providing containment, protection and support, and an electrode assembly 20 for realizing electrical functions. The housing 10 encloses a containment cavity, and the electrode assembly 20 is disposed in the containment cavity. At the same time, an electrolyte may also be disposed in the containment cavity, and the electrode assembly 20 is immersed in the electrolyte.

[0086] Optionally, the electrode assembly 20 can be made by stacking or winding a positive electrode 21, an insulating member 22 and a negative electrode 23, wherein the insulating member 22 is disposed between the positive electrode 21 and the negative electrode 23 to provide electrical insulation and to serve as an ion permeation channel.

[0087] The separator 22 has two surfaces disposed opposite each other in its thickness direction X, at least one of which has a groove 221. The groove 221 has its opening located on the surface and is recessed along the thickness direction X. The grooves 221 may have the same or similar thickness, or the depth of the grooves 221 may increase from the edge to the center in the width direction of the separator 22, so that more electrolyte can be retained in the less wetted central region.

[0088] In the separator 22, multiple grooves 221 can be provided on the same side surface. These grooves 221 can be spaced apart from each other and arranged at least partially along the length of the separator 22 to more uniformly improve the electrolyte retention capacity of the separator 22. Optionally, each groove 221 can be spaced apart from the edge of the separator 22 to specifically improve the electrolyte retention capacity of the internal areas of the separator 22 that are not easily wetted.

[0089] It is understandable that the depth of each groove 221 on the separator 22 is less than the thickness of the separator 22. If grooves 221 are provided on both opposite sides of the separator 22, the sum of the depths of the two opposite grooves 221 should be less than the depth of the separator 22. That is, the separator 22 should remain intact and not penetrated, so that the separator 22 can achieve its isolation function while improving its liquid retention capacity.

[0090] In the technical solution of this application embodiment, an electrode assembly 20 is disposed within the outer casing 10 of the battery cell 100. The electrode assembly 20 further includes a positive electrode 21, a separator 22, and a negative electrode 23 stacked together. The separator 22 has a groove 221 on at least one surface of its thickness. By providing the groove 221 on the separator 22, space can be provided for the electrolyte, improving the separator 22's ability to retain and store the electrolyte, thereby improving the cycle performance of the battery cell 100. At the same time, the groove 221 can provide a certain gap between the separator 22 and the electrode, thereby improving the smoothness of venting of the electrode assembly 20 during operation, thus improving the reliability of the battery cell 100.

[0091] In some optional embodiments, the spacer 22 has grooves 221 on both sides opposite to each other in the thickness direction X, and the grooves 221 on opposite sides of the spacer 22 in the thickness direction X are spaced apart from each other.

[0092] Optionally, in order to further improve the ability of the separator 22 to retain and preserve electrolyte, groove 221 structures can be provided on both opposite sides of the separator 22. The groove 221 structures located on the two sides are spaced apart from each other to reduce the possibility of forming a through path along the thickness direction X on the separator 22 and reducing reliability.

[0093] Specifically, in embodiments where the grooves 221 on both sides are at least partially aligned, the sum of the depths of the two grooves 221 can be less than the thickness of the spacer 22, so that a partial insulating layer is retained between the two grooves 221. In embodiments where the grooves 221 on both sides are staggered, the depth of each groove 221 can be less than the thickness of the spacer 22, so that the groove 221 does not penetrate the spacer 22.

[0094] Optionally, the grooves 221 located on the two sides can have the same or similar shape, size and depth, and the grooves 221 on both sides can adopt the same or similar arrangement to facilitate processing.

[0095] By simultaneously providing grooves 221 on both sides of the separator 22, the liquid retention and liquid holding capabilities of the separator 22 can be further improved, thereby further improving the cycle performance of the battery cell 100.

[0096] In some optional embodiments, the groove 221 includes a first groove 222 and a second groove 223 respectively disposed on opposite sides of the insulating member 22, and the first groove 222 and the second groove 223 are symmetrically disposed in the thickness direction X.

[0097] Optionally, in an embodiment where grooves 221 are provided on both sides of the spacer 22, the grooves 221 on both sides can be referred to as the first groove 222 and the second groove 223, respectively. The first groove 222 and the second groove 223 can be symmetrically arranged in the thickness direction X of the spacer 22, that is, the first groove 222 and the second groove 223 can be symmetrically arranged with respect to a reference surface, which can be parallel to the surface of the spacer 22, that is, the reference surface can be perpendicular to the thickness direction X.

[0098] In an embodiment where a first groove 222 and a second groove 223 are respectively provided on both sides of the separator 22, the depths of the two grooves 221 can be the same or similar, and the sum of the depths of the first groove 222 and the second groove 223 is less than the thickness of the separator 22.

[0099] By symmetrically arranging the first groove 222 and the second groove 223 on both sides of the separator 22, the overall structural strength of the separator membrane can be made more uniform, reducing the possibility of stress concentration leading to damage to the separator 22.

[0100] In some alternative embodiments, the size of the spacer 22 is L1 in the thickness direction X, and the sizes of the two grooves 221 are L2 and L3 respectively; L2+L3<L1, 1μm≤L2+L3-0.5L1≤3μm.

[0101] In an embodiment where grooves 221 are provided on both sides of the isolation member 22, the size of the isolation member 22 can be denoted as L1 along the thickness direction X, and the recess depths of the grooves 221 on both sides can be denoted as L2 and L3, respectively.

[0102] Based on this, the sum of L2 and L3 can be less than the thickness L1 of the spacer 22, so that the grooves 221 on both sides are spaced apart to maintain the reliability of the spacer 22. At the same time, 1μm≤L2+L3-0.5L1≤3μm can be selected, that is, the difference between the sum of the depths of the two grooves 221 and half the thickness of the spacer 22 can be selected to be between 1μm and 3μm, for example, it can be any one of 1μm, 1.5μm, 2μm, 2.5μm, 3μm or any two of them.

[0103] By limiting the difference between the sum of the depths of the grooves 221 and the thickness of the separator 22, the depth of the grooves 221 can be matched with the thickness of the separator 22, and the grooves 221 can have a suitable depth, thereby reducing the possibility of the separator being too thin and thus breaking, and at the same time reducing the possibility of the grooves 221 being too shallow and thus having an insignificant liquid retention effect.

[0104] In some alternative embodiments, the size L1 of the spacer 22 is 7μm-15μm in the thickness direction X, and the sizes L2 and L3 of the groove 221 are both 2μm-5μm.

[0105] Based on the aforementioned range, the size L1 of the spacer 22 can be further defined as 7μm-15μm, for example, it can be selected as any one of 7μm, 9μm, 11μm, 13μm, 15μm or any two thereof. Correspondingly, the depths L2 and L3 of the grooves 221 located on both sides of the spacer 22 can both be further defined as 2μm-5μm, for example, it can be selected as any one of 2μm, 3μm, 4μm, 5μm or any two thereof.

[0106] By further limiting the thickness of the separator 22 and the depth of the groove 221, it is possible to improve the liquid retention capacity of the separator 22 while giving it higher structural strength and reliability.

[0107] Please see Figure 7 , Figure 7 for Figure 5 Another cross-sectional view at A-A' is shown. In some alternative embodiments, the groove 221 has an opening 224 and a bottom wall 225 opposite each other in the thickness direction X, the area of ​​the opening 224 being smaller than the area of ​​the bottom wall 225, and the orthographic projection of the opening 224 lying within the outline of the orthographic projection of the bottom wall 225 along the thickness direction X.

[0108] Optionally, the groove 221 can adopt a structure with an inverted trapezoidal cross-section, that is, the area of ​​the bottom of the groove 221 is larger than the area of ​​the opening 224. Specifically, the plane containing the bottom wall 225 of the groove 221 can be parallel or nearly parallel to the surface of the separator 22, the opening 224 of the groove 221 and the bottom wall 225 can have the same or similar shape, and the area of ​​the opening 224 can be smaller than the area of ​​the bottom wall 225.

[0109] Furthermore, along the thickness direction X of the separator 22, the orthographic projection of the opening 224 of the groove 221 can be located within the outline of the orthographic projection of the bottom wall 225. It is further optional that the orthographic projection of the opening 224 and the orthographic projection of the bottom wall 225 are concentrically arranged so that the inclination of each sidewall of the groove 221 is closer and its structure is uniform and easy to process.

[0110] By making the area of ​​the opening 224 of the groove 221 smaller than the area of ​​the bottom wall 225, the groove 221 can be made into a structure with a small opening 224 and a large bottom. This allows it to have more space to accommodate electrolytes while making it difficult for electrolytes to flow out of the groove 221. As a result, the groove 221 can gradually release electrolytes during the working cycle of the battery cell 100, thereby further improving the liquid retention capacity of the separator 22.

[0111] In some optional embodiments, both the opening 224 and the bottom wall 225 are rectangular, with the edge dimensions of the opening 224 being 10mm-50mm and the edge dimensions of the bottom wall 225 being 14mm-70mm.

[0112] Optionally, to further facilitate the processing of the separator 22, the opening 224 and the bottom wall 225 of the groove 221 can be rectangular, making the internal space of the groove 221 frustum-shaped, or more preferably, the opening 224 and the bottom wall 225 of the groove 221 can be square.

[0113] In embodiments where both the opening 224 and the bottom wall 225 of the groove 221 are rectangular, the long and short sides of the opening 224 can both be between 10mm and 50mm, for example, any one of 10mm, 20mm, 30mm, 40mm, and 50mm, or any two of them. Similarly, the long and short sides of the bottom wall 225 of the groove 221 can both be between 14mm and 70mm, for example, any one of 14mm, 34mm, 54mm, and 70mm, or any two of them.

[0114] By defining the shape and size of the groove 221, the groove 221 can be made easy to process and has a suitable capacity, thereby further improving its liquid retention and creeping effects.

[0115] Please refer to the following: Figure 8 and Figure 9 , Figure 8 This is a schematic diagram of the structure of the isolation member provided in some other embodiments of this application. Figure 9 for Figure 8 A cross-sectional view at point B-B' is shown.

[0116] In some optional embodiments, at least a portion of the groove 221 includes a central groove 226 and a plurality of sub-grooves 227, the plurality of sub-grooves 227 being arranged sequentially along the circumference of the central groove 226, and the central groove 226 being connected to the plurality of sub-grooves 227 respectively.

[0117] Optionally, each groove 221 can be configured to consist of multiple parts, including a central groove 226 located at the center and multiple sub-grooves 227 arranged around the central groove 226. These sub-grooves 227 can be arranged sequentially along the circumference of the central groove 226 and connected to the central groove 226 respectively. Adjacent sub-grooves 227 can be spaced apart, or adjacent sub-grooves 227 can be interconnected, for example, by providing additional channels between sub-grooves 227, connecting sub-grooves 227 together, or partially overlapping sub-grooves 227.

[0118] Optionally, the central groove 226 may have a larger area than the sub-grooves 227, so that each sub-groove 227, after being arranged circumferentially, can be connected to and communicate with the central groove 226. The central groove 226 and the sub-grooves 227 may have the same or different shapes, and the multiple sub-grooves 227 may all be set with the same shape and area, and the multiple sub-grooves 227 may be arranged in a centrally symmetrical manner.

[0119] It is understandable that the central symmetry setting here refers to the orthographic projection of the groove 221 along the thickness direction X of the separator 22, and the connection of the center point of the orthographic projection of each sub-groove 227 with the center point of the orthographic projection of the central groove 226 by a straight line. The included angle between each connecting line can be selected to have the same size. By rotating the orthographic projection of each sub-groove 227 with the connecting line as the radius, it can be made to coincide with the orthographic projection of other sub-groove 227.

[0120] Optionally, in embodiments where the groove 221 includes a central groove 226 and a sub-groove 227, the groove 221 can also be configured as having a smaller opening 224 and a larger bottom wall 225, that is, the groove 221 has inwardly inclined sidewalls, thereby enabling the electrolyte to diffuse outward uniformly and continuously, while further improving the liquid retention and liquid holding capacity of the groove 221.

[0121] By configuring the groove 221 to include a central groove 226 and multiple sub-grooves 227, the electrolyte residing in the central groove 226 can be uniformly and continuously diffused into the sub-grooves 227 while expanding the overall area of ​​the groove 221, and then further diffused into the area of ​​the separator 22 adjacent to the sub-grooves 227, thereby providing a continuous diffusion supply and further improving the liquid retention and liquid holding capacity of the separator 22.

[0122] In some alternative embodiments, a plurality of sub-slots 227 are arranged at equal intervals along the circumference of the central slot 226, and the plurality of sub-slots 227 have the same area.

[0123] Optionally, in an embodiment where the groove 221 includes a central groove 226 and a plurality of sub-grooves 227, the sub-grooves 227 can be arranged at equal intervals around the central groove 226, and the shape and area of ​​each sub-grooves 227 can be the same. At the same time, the distance between the central axis of each sub-grooves 227 and the central axis of the central groove 226 can be the same, so that the distribution of the sub-grooves 227 is more uniform.

[0124] Optionally, based on the aforementioned equal-interval distribution and the same area and central axis spacing, the sub-grooves 227 in each groove 221 can be positioned in the same way relative to the central groove 226, so as to further ensure uniform wetting and diffusion of the electrolyte, and at the same time, to facilitate processing, such as by pressing and forming with rollers of the same shape.

[0125] By arranging multiple sub-cells 227 at equal intervals, the diffusion efficiency of electrolyte in all directions can be further made uniform, thereby improving the uniformity of electrolyte wetting.

[0126] In some alternative embodiments, the central groove 226 is circular, elliptical, or polygonal, and the sub-grooves 227 are rectangular, circular, elliptical, or polygonal.

[0127] Optionally, to make the sub-cells 227 more evenly distributed around the central trough 226, the central trough 226 can be circular, elliptical, or polygonal, wherein the polygon can be further selected as a regular polygon with 6 or more sides. In an embodiment where the central trough 226 is set as a regular polygon, the number of sub-cells 227 can be the same as the number of sides of the polygon, and each sub-cell 227 can be located at the intersection of every two adjacent sides of the central trough 226, so as to facilitate the uniform distribution of electrolyte to each sub-cell 227.

[0128] Optionally, the sub-groove 227 may be rectangular, circular, elliptical, or polygonal in shape to facilitate machining and connection with the central groove 226.

[0129] It is understood that the definition of the shape of the central groove 226 and the sub-groove 227 here refers to extending the outline of the two grooves along the outline of the shape. As for the overall shape, the central groove 226 and the sub-groove 227 may have overlapping areas. That is, according to the shape of the central groove 226 and the sub-groove 227, there is an area in the groove 221 that is part of both the central groove 226 and the sub-groove 227.

[0130] By adjusting the shape of the central groove 226 and the sub-groove 227, the groove 221 can be easily processed as a whole, and the central groove 226 and the sub-groove 227 can be easily connected to each other and disperse the electrolyte.

[0131] In some optional embodiments, the central groove 226 and the plurality of sub-grooves 227 are all circular, with the radius of the central groove 226 being 10mm-60mm and the radius of the sub-grooves 227 being 5mm-10mm.

[0132] Optionally, in embodiments where the groove 221 includes a central groove 226 and multiple sub-grooves 227, each central groove 226 and sub-grooves 227 may be circular to facilitate the processing and positioning of the sub-grooves 227, while allowing the groove 221 to release the electrolyte more evenly and slowly to the surrounding area. In embodiments where the central groove 226 and each sub-grooves 227 are circular, the center of each sub-groove 227 may be located on the edge line of the central groove 226 to facilitate the positioning of the sub-grooves 227 and their uniform distribution in the circumferential direction.

[0133] In embodiments where both the central groove 226 and the sub-groove 227 are circular, the radius of the central groove 226 can be selected from 10mm to 60mm, for example, any one of 10mm, 30mm, 50mm, and 60mm or between any two of them, and the radius of the sub-groove 227 can be selected from 5mm to 10mm, for example, any one of 5mm, 7mm, 9mm, and 10mm or between any two of them.

[0134] By limiting the dimensions of the central tank 226 and the sub-tank 227, both can have suitable areas, reducing the possibility that the electrolyte retention effect will decrease due to the two tanks being too small, and at the same time reducing the possibility that the structural strength of the separator 22 will decrease due to the two tanks being too large, or that it will break when bent or under pressure.

[0135] In some alternative embodiments, a plurality of grooves 221 located on the surface of the spacer 22 are arranged in an array.

[0136] Optionally, in embodiments where multiple grooves 221 are provided on the same surface of the spacer 22, these grooves 221 may be arranged in an array. Exemplarily, the multiple grooves 221 may be arranged in multiple rows, with each row of grooves 221 extending in a direction parallel to the extending direction of the spacer 22, and each groove 221 in each row may be equally spaced along this extending direction. Furthermore, the spacing between any two adjacent rows of grooves 221 may be the same.

[0137] By arranging multiple grooves 221 in an array on the same side surface, the grooves 221 can be further evenly distributed on the separator 22, thereby further improving the uniformity of electrolyte wetting and retention on the separator 22.

[0138] In some alternative embodiments, the spacer 22 includes a substrate and a coating disposed on at least one of opposite surfaces of the substrate, with a groove 221 disposed in the coating.

[0139] Optionally, the separator 22 may include a multi-layered film structure, specifically a substrate and a coating disposed on at least one surface of the substrate. The substrate may be a sheet-like thin film structure, and the coating applied to at least one surface of the substrate can increase the overall thickness and structural strength of the separator 22, reducing the probability of breakage during winding.

[0140] Based on this, the groove 221 can be provided in the coating. Specifically, the recess depth of the groove 221 can be less than or equal to the thickness of the coating, so that the groove 221 is entirely within the structural range of the coating and the substrate maintains a uniform thickness throughout.

[0141] When manufacturing the separator 22, the groove 221 can be formed during the coating process using a coating machine. For example, the coating thickness can be adjusted using a coating machine so that the thickness of a preset area is less than the thickness of other areas, thereby forming the groove 221. Exemplarily, a coating with a thickness difference can be formed by multiple coatings, or the groove 221 can be formed by removing part of the coating.

[0142] By manufacturing a coating and locally thinning it to form the groove 221, the processing of the groove 221 is simplified and easier to form, thereby improving production efficiency. At the same time, since the groove 221 is located only within the coating and not formed on the base film, the possibility of damage to the separator 22 during winding or folding is reduced, improving the reliability of the battery cell 100.

[0143] Secondly, according to the embodiments of this application, a battery device 200 is provided, including a housing 30 and a battery cell 100 as described in any embodiment of the first aspect, wherein the battery cell 100 is disposed in the housing 30.

[0144] Thirdly, according to the embodiments of this application, an electrical device is provided, including the battery device 200 in any embodiment of the second aspect, the battery device 200 being used to provide electrical energy.

[0145] The battery device 200 and the electrical equipment in this embodiment have all the beneficial effects of the battery cell 100 in the first aspect. For details, please refer to the specific description of the battery cell 100 in the above embodiments. This embodiment will not repeat the description here.

[0146] This application provides a battery cell 100, including a housing 10 and an electrode assembly 20. The electrode assembly 20 is disposed in the housing 10 and includes a positive electrode 21, a separator 22 and a negative electrode 23 stacked together. At least one of the two surfaces of the separator 22 disposed opposite to each other in its thickness direction X has a plurality of grooves 221. The plurality of grooves 221 are recessed along the thickness direction X and are spaced apart from each other.

[0147] The groove 221 includes a first groove 222 and a second groove 223 respectively disposed on opposite sides of the isolator 22. The first groove 222 and the second groove 223 are symmetrically arranged in the thickness direction X. In the thickness direction X, the size of the isolator 22 is L1, and the sizes of the two grooves 221 are L2 and L3 respectively; L2+L3<L1, 1μm≤L2+L3-0.5L1≤3μm. The groove 221 has an opening 224 and a bottom wall 225 opposite to each other in the thickness direction X. The area of ​​the opening 224 is smaller than the area of ​​the bottom wall 225. Along the thickness direction X, the orthographic projection of the opening 224 lies within the contour range of the orthographic projection of the bottom wall 225.

[0148] 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 device, comprising: a shell; an electrode assembly arranged in the shell, the electrode assembly comprising a positive electrode sheet, a separator and a negative electrode sheet arranged in layers, at least one of the two opposite surfaces of the separator in the thickness direction of the separator is provided with a plurality of grooves, and the plurality of grooves are recessed and arranged at intervals in the thickness direction.

2. The battery cell of claim 1, wherein, The grooves are arranged on both sides of the separator in the thickness direction, and the grooves on the two opposite sides of the separator are arranged at intervals in the thickness direction.

3. The battery cell of claim 2, wherein, The grooves comprise a first groove and a second groove arranged on the two opposite surfaces of the separator respectively, and the first groove and the second groove are symmetrically arranged in the thickness direction.

4. The battery cell of claim 2, wherein, In the thickness direction, the size of the separator is L1, and the sizes of the two grooves are L2 and L3 respectively; L2+L3 < L1, 1 mu m <= L2+L3-0.5L1 <= 3 mu m.

5. The battery cell of claim 4, wherein, In the thickness direction, the size L1 of the separator is 7 mu m-15 mu m, and the sizes L2 and L3 of the grooves are both 2 mu m-5 mu m.

6. The battery cell of claim 1, wherein, The grooves have opposite openings and bottom walls in the thickness direction, the area of the opening is smaller than that of the bottom wall, and the orthogonal projection of the opening is within the orthogonal projection of the bottom wall in the thickness direction.

7. The battery cell of claim 6, wherein, The opening and the bottom wall are both rectangular, the edge size of the opening is 10 mm-50 mm, and the edge size of the bottom wall is 14 mm-70 mm.

8. The battery cell of any one of claims 1-6, wherein, At least part of the grooves comprises a center groove and a plurality of sub-grooves, the plurality of sub-grooves are arranged along the circumference of the center groove in sequence, and the center groove is communicated with the plurality of sub-grooves respectively.

9. The battery cell of claim 8, wherein, The plurality of sub-grooves are arranged at equal intervals along the circumference of the center groove, and the areas of the plurality of sub-grooves are the same.

10. The battery cell of claim 8, wherein, The center groove is circular, elliptical or polygonal, and the sub-grooves are rectangular, circular, elliptical or polygonal.

11. The battery cell of claim 10, wherein, The center groove and the plurality of sub-grooves are both circular, the radius of the center groove is 10 mm-60 mm, and the radius of the sub-groove is 5 mm-10 mm.

12. The battery cell of claim 1, wherein, The plurality of grooves on the surface of the separator are arranged in an array.

13. The battery cell of claim 1, wherein, The separator comprises a substrate and a coating arranged on at least one of the two opposite surfaces of the substrate, and the grooves are arranged in the coating.

14. A battery device characterized by comprising: The application also relates to a battery device, comprising: a box body; a plurality of battery monomers according to any one of claims 1-13, the battery monomers are arranged in the box body.

15. An electrical device, characterized by The application also relates to a battery device for providing electric energy.

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