Battery monomer, battery device, power utilization device and energy storage device

Abstract

The utility model provides a battery monomer, a battery device, a power utilization device and an energy storage device. The battery monomer comprises a shell and an electrode assembly, the shell comprises a top wall and a bottom wall opposite to the top wall along a first direction, and the bottom wall is used for supporting the electrode assembly; the electrode assembly comprises a separator, the separator comprises a base film and a first ceramic film layer stacked with the base film, a first groove is formed in the side, away from the base film, of the first ceramic film layer, and the extending direction of the first groove intersects with the plane where the top wall is located or the plane where the bottom wall is located. The side wall of the first groove is composed of the first ceramic film layer, and the bottom wall of the first groove is composed of the first ceramic film layer or the base film. The service life of the battery monomer is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a battery monomer, a battery device, a power utilization device and an energy storage device. BACKGROUND

[0002] In recent years, with the application range of battery monomer becoming more and more extensive, the battery monomer is widely applied to energy storage power supply systems such as water, fire, wind and solar power stations, and many fields such as electric tools, electric bicycles, electric motorcycles, electric vehicles, aerospace, etc. Because the battery monomer has achieved great development, higher requirements are put forward for its performance, etc.

[0003] For example, it is required that the battery monomer has a prolonged service life. The existing battery monomer has the problem that the negative pole piece is prone to lithium precipitation due to poor electrolyte infiltration, which affects the service life of the battery. CONTENT OF THE UTILITY MODEL

[0004] To solve the above technical problems, the present application provides a battery monomer, a battery device, a power utilization device and an energy storage device. The battery monomer has a prolonged service life.

[0005] The first aspect of the present application provides a battery monomer, comprising: a shell and an electrode assembly; the shell comprises a top wall and a bottom wall arranged opposite to the top wall along a first direction, the bottom wall is used for supporting the electrode assembly; the electrode assembly comprises a separator, the separator comprises a base film and a first ceramic film layer arranged in stack with the base film, a first groove is opened on a side of the first ceramic film layer away from the base film, an extension direction of the first groove intersects with a plane where the top wall is located or a plane where the bottom wall is located, and a side wall of the first groove is composed of the first ceramic film layer, and a bottom wall of the first groove is composed of the first ceramic film layer or the base film.

[0006] In the present application, the battery monomer comprises a first ceramic film layer, a first groove is opened on a side of the first ceramic film layer away from the base film, thereby the liquid guiding function of the first groove can be used to guide the electrolyte deposited at the bottom of the shell upward, thereby reducing the performance decline of the upper battery monomer due to insufficient electrolyte infiltration, and prolonging the service life of the battery monomer. Further, since the side wall of the first groove is composed of the first ceramic film layer, the volume of the first ceramic film layer changes little with temperature, thereby the stability of the structure of the first groove can be maintained, and the liquid guiding function of the first groove can be fully played. Therefore, the battery monomer disclosed in the present application has a prolonged service life.

[0007] In some embodiments, the bottom wall of the first groove is formed by the first ceramic film layer. Since the side wall and the bottom wall of the first groove are both formed by the first ceramic film layer, i.e., there is a first ceramic film layer between the bottom wall of the first groove and the base film, the first ceramic film layer can inhibit the volume expansion and contraction of the base film, thereby maintaining the stability of the first groove structure and facilitating the first groove to fully play its liquid guiding function.

[0008] In some embodiments, the first groove extends to an end of the first ceramic film layer close to the top wall side in the first direction. Such a design helps the first groove to guide the electrolyte to the top of the battery cell, promotes the uniform distribution of the electrolyte inside the battery cell, and thereby reduces the performance degradation of the upper battery cell due to insufficient electrolyte immersion and prolongs the service life of the battery cell.

[0009] In some embodiments, the first groove extends to an end of the first ceramic film layer close to the bottom wall side in the first direction. Such a design helps the electrolyte deposited at the bottom of the shell to flow upward, thereby reducing the risk of the battery caused by insufficient electrolyte and prolonging the service life of the battery.

[0010] In some embodiments, the angle between the central axis of the first groove and the first direction is greater than or equal to 0 degrees and less than 90 degrees. By setting the angle between the central axis of the first groove and the first direction in the above range, it is beneficial to increase the area of the first groove, thereby improving the wettability of the electrolyte and further prolonging the service life of the battery cell.

[0011] In some embodiments, the angle between the central axis of the first groove and the first direction is 30 degrees to 60 degrees. By setting the angle between the central axis of the first groove and the first direction in the above range, it is beneficial to further prolong the service life of the battery cell.

[0012] In some embodiments, the cross-sectional area of the first groove in a plane perpendicular to the first direction is 0.001 mm 2 to 0.24 mm 2 . By controlling the cross-sectional area of the first groove in the above range, it is helpful for the first groove to achieve capillary action, thereby increasing the flow speed of the electrolyte in the first groove and improving the wettability of the battery cell, thereby prolonging the service life of the battery cell.

[0013] In some embodiments, the cross-sectional area of the first groove in a plane perpendicular to the first direction is 0.01 mm 2 to 0.24 mm 2 . By controlling the cross-sectional area of the first groove in the above range, it is beneficial to further prolong the service life of the battery cell.

[0014] In some embodiments, the ratio of the total area of the first recesses projected on the first surface to the area of the first surface is 17% to 71%, the first surface being the surface of the first ceramic film layer facing the base film. By controlling the ratio of the total area of the first recesses projected on the first surface to the area of the first surface in the above range, the structural strength and the wettability of the separator are balanced, thereby further prolonging the service life of the battery cell.

[0015] In some embodiments, the ratio of the total area of the first recesses projected on the first surface to the area of the first surface is 20% to 50%. By controlling the ratio of the total area of the first recesses projected on the first surface to the area of the first surface in the above range, the service life of the battery cell is further prolonged.

[0016] In some embodiments, the size of the first recess in the second direction is smaller than the size of the first recess in the third direction, the second direction being the stacking direction of the base film and the first ceramic film layer, and the first direction, the second direction and the third direction being perpendicular to each other. By the above arrangement, the first recess is formed.

[0017] In some embodiments, the size of the first recess in the second direction is 0.1 μm to 8 μm. By setting the size of the first recess in the second direction in the above range, the first recess realizes capillary action, thereby increasing the flow speed of the electrolyte in the first recess, improving the wettability of the battery cell, and prolonging the service life of the battery cell.

[0018] In some embodiments, the size of the first recess in the second direction is 0.5 μm to 8 μm. By setting the size of the first recess in the second direction in the above range, the service life of the battery cell is further prolonged.

[0019] In some embodiments, the size of the first recess in the third direction is 1 mm to 30 mm. By controlling the size of the first recess in the third direction in the above range, the structural strength and the wettability of the separator are balanced, thereby prolonging the service life of the battery cell.

[0020] In some embodiments, the size of the first recess in the third direction is 3 mm to 30 mm. By controlling the size of the first recess in the third direction in the above range, the service life of the battery cell is further prolonged.

[0021] In some embodiments, the distance between the central axes of two adjacent first grooves is 10-60 mm. By controlling the distance between the central axes of two adjacent first grooves within the above range, the structural strength and wettability of the spacer are balanced, thereby prolonging the service life of the battery cell.

[0022] In some embodiments, the distance between the central axes of two adjacent first grooves is 15-30 mm. By controlling the distance between the central axes of two adjacent first grooves within the above range, the service life of the battery cell is further prolonged.

[0023] In some embodiments, the first ceramic film layer comprises ceramic particles. The ceramic particles have a low coefficient of thermal expansion. The use of the first ceramic film layer comprising ceramic particles helps to further inhibit the volume expansion and contraction of the base film, thereby maintaining the structural stability of the first grooves, enabling the first grooves to fully play their liquid guiding function, and prolonging the service life of the battery cell.

[0024] In some embodiments, the ceramic particles comprise first particles and / or second particles, the volume average particle size Dv50 of the first particles is 0.1-2 μm, and the volume average particle size Dv50 of the second particles is greater than 2 μm and less than or equal to 5 μm. By using the first particles and / or second particles with the above particle sizes, the service life of the battery cell is prolonged. In particular, when the first particles and the second particles with different particle sizes are used at the same time, the smaller first particles can be filled between the larger second particles, thereby forming gaps between the first particles and the second particles. The gaps can serve as flow channels for the electrolyte, further improving the wettability of the battery cell, and thereby further prolonging the service life of the battery cell.

[0025] In some embodiments, the ceramic particles comprise at least one of aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, tin dioxide, boehmite, magnesium oxide, zinc oxide, barium sulfate, magnesium nitride, or barium titanate. The above materials have good flame retardant effect, good chemical stability, good thermal stability, and other advantages. The use of ceramic particles comprising the above materials helps to further improve the thermal stability of the battery cell.

[0026] In some embodiments, a second groove is formed on the side of the first ceramic film layer away from the base film, the second groove intersects and communicates with the first groove. By providing the second groove, the electrolyte is more evenly distributed on the surface of the ceramic film layer, the performance degradation of the battery cell caused by poor local wettability is improved, and the service life of the battery cell is further prolonged.

[0027] In some embodiments, the battery cell further comprises a positive electrode tab and a negative electrode tab, and the first ceramic film layer is laminated on a surface of the base film facing the positive electrode tab or the negative electrode tab. In this way, the battery cell has a prolonged service life.

[0028] In some embodiments, the separator further comprises a liquid guiding layer laminated on a surface of the base film away from the first ceramic film layer, and the liquid guiding layer comprises a second ceramic film layer, the second ceramic film layer is provided with a third groove on a side thereof away from the base film, a sidewall of the third groove is formed by the second ceramic film layer, and a bottom wall of the third groove is formed by the base film; or the liquid guiding layer comprises a bonding layer, the bonding layer is provided with a fourth groove on a side thereof away from the base film, a sidewall of the fourth groove is formed by the bonding layer, and a bottom wall of the fourth groove is formed by the base film or the bonding layer.

[0029] In this embodiment, the flow channel of the electrolyte is increased by providing a groove (third groove or fourth groove) on a side of the liquid guiding layer away from the base film, so as to further improve the wettability of the battery cell and prolong the service life of the battery cell.

[0030] In some embodiments, the separator further comprises a functional layer laminated on a surface of the base film away from the first ceramic film layer, and the functional layer satisfies at least one of the following conditions: the thermal shrinkage rate of the composite of the functional layer and the base film is reduced by more than 10% relative to the thermal shrinkage rate of the base film; and the bonding force between the functional layer and the positive electrode tab or the negative electrode tab after thermal pressing is greater than the bonding force between the base film and the positive electrode tab or the negative electrode tab after thermal pressing. The provision of the functional layer helps to improve the structural stability of the separator, thereby prolonging the service life of the battery cell.

[0031] In some embodiments, the positive electrode tab, the separator, and the negative electrode tab are arranged in sequence. This design helps to prolong the service life of the battery cell.

[0032] In some embodiments, the laminated body formed by the positive electrode tab, the separator, and the negative electrode tab is wound along a winding axis, and the winding axis is parallel to the first direction. In the above battery cell, since the electrode tabs (positive electrode tab and negative electrode tab) are in a curled state, the space waste of the electrode assembly is reduced, which helps to achieve a high volumetric energy density of the battery cell. In addition, the design of the first groove helps the electrolyte to penetrate more effectively into the inner layer of the curled electrode tab, so that the battery cell has a prolonged service life while taking into account a high volumetric energy density.

[0033] In some embodiments, the shell comprises a housing and a cover, the housing has an opening, the cover closes the opening, and the cover forms the top wall. The battery monomer has a long service life.

[0034] In some embodiments, the shell comprises a housing and a cover, the housing has an opening, the cover closes the opening, and the cover forms the bottom wall. The battery monomer has a long service life.

[0035] In some embodiments, the shell comprises a housing and a cover, the housing comprises two first sides arranged oppositely and two second sides arranged oppositely, the first sides and the second sides form an opening, the cover closes the opening, one of the first sides forms the bottom wall, and the other of the first sides forms the top wall. The battery monomer has a long service life.

[0036] In some embodiments, the area of the first side is smaller than the area of the second side. The battery monomer has a long service life.

[0037] The second aspect of the present application provides a battery device comprising at least one battery monomer provided by the first aspect. Since the battery monomer provided by the embodiments of the present application has a long service life, the battery device containing the battery monomer also has a long service life.

[0038] The third aspect of the present application provides a power consumption device, which comprises at least one of the battery monomer and the battery device described above. Since the battery monomer provided by the embodiments of the present application has a long service life, the power consumption device containing the battery monomer also has a long service life.

[0039] The fourth aspect of the present application provides an energy storage device, which comprises at least one of the battery monomer and the battery device described above. Since the battery monomer provided by the embodiments of the present application has a long service life, the energy storage device containing the battery monomer also has a long service life.

[0040] Effect of the utility model

[0041] The present application provides a battery monomer. The first groove with liquid guiding function is arranged in the battery monomer. The first groove can guide the electrolyte deposited at the bottom of the shell upward by the liquid guiding function of the first groove, thereby reducing the performance decline of the upper battery monomer caused by insufficient electrolyte infiltration, prolonging the service life of the battery monomer. Further, the sidewall of the first groove is composed of the first ceramic film layer, the volume of the first ceramic film layer changes little with temperature, thereby maintaining the stability of the structure of the first groove, and further facilitating the first groove to fully play its liquid guiding function. Therefore, the battery monomer disclosed in the present application has a long service life. Attached Figure Description

[0042] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. 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.

[0043] In the attached diagram:

[0044] Figure 1 Structural schematic diagrams of vehicles provided for some embodiments of this application;

[0045] Figure 2 Exploded perspective view of a battery provided for some embodiments of this application;

[0046] Figure 3 An exploded perspective view of a battery cell provided for some embodiments of this application;

[0047] Figure 4 for Figure 3 A cross-sectional view of one of the electrode components on the aa' plane;

[0048] Figure 5 Perspective views of electrode assemblies provided for other embodiments of this application;

[0049] Figure 6 Perspective view of the isolation element provided for some embodiments of this application;

[0050] Figure 7 A cross-sectional schematic view of the spacer in the YZ plane for some embodiments of this application;

[0051] Figure 8 A schematic cross-sectional view of the spacer in the XY plane for some embodiments of this application;

[0052] Figure 9 for Figure 8 An enlarged view of region A in the provided isolation component;

[0053] Figure 10 A perspective view of the isolation element provided for some other embodiments of this application.

[0054] Explanation of reference numerals in the attached figures

[0055] 1000 vehicles; 100 batteries; 200 controllers; 300 motors; 10 battery boxes; 20 individual battery cells; 101 box cover; 102 box body;

[0056] 21 housing; 22 electrode assembly; 23 positive electrode terminal; 24 negative electrode terminal; 25 pressure relief structure; 211 housing; 212 cover; 221 negative electrode tab; 222 negative electrode lug; 223 separator; 224 positive electrode tab; 225 positive electrode lug; 1 base film; 2 first ceramic film layer; 3 liquid guiding layer; 1a first groove; 2a second groove; Z first direction; X second direction; Y third direction. DETAILED DESCRIPTION

[0057] The embodiments of the technical solutions of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0058] 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 belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the terms "comprising" and "having," and any variations thereof, as used in the specification and claims and the aforementioned description of the drawings, are intended to cover not exclusively inclusive.

[0059] In the description of the embodiments of the present application, the technical terms "first", "second", "third" and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0060] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0061] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents the "or" relationship between the front and rear associated objects.

[0062] In the description of the embodiments of the present application, the directions or positional relationships indicated by the technical terms "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential" and the like are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed, operated or used in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0063] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0064] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical term "contact" should be understood broadly, which can be direct contact or contact through an intermediate medium layer, and can be contact between two objects in contact without interaction force, or contact between two objects in contact with interaction force.

[0065] In the following, the present application will be described in detail.

[0066] At present, new energy batteries are more and more widely used in life and industry. New energy batteries are not only applied to energy storage power supply systems such as hydroelectric, thermal, wind and solar power stations, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also increasing.

[0067] The battery mentioned in the embodiments of the present application can include one or more battery monomers to provide a single physical module with higher voltage and capacity. When there are multiple battery monomers, the multiple battery monomers are connected in series, parallel or mixed connection through a bus component. For example, the battery mentioned in the present application can include a battery module or a battery pack, etc. The battery generally includes a battery box for packaging one or more battery monomers. The battery box can avoid the influence of liquid or other foreign matters on the charging or discharging of the battery monomers. The battery can also be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0068] In the present application, the battery monomer can include a lithium ion secondary battery, a lithium ion primary battery, a lithium-sulfur battery monomer, a sodium lithium ion battery monomer, a sodium ion battery monomer, or a magnesium ion battery monomer, etc. The present application embodiment does not limit this. The battery monomer can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc. The present application embodiment does not limit this either. The battery monomer is generally divided into three types according to the packaging method: cylindrical battery monomers, square battery monomers, and soft package battery monomers. The present application embodiment does not limit this either.

[0069] The battery monomer includes an electrode assembly and an electrolyte, and the electrode assembly is used to generate electric energy as the core component of the battery monomer. The electrode assembly at least includes a positive electrode sheet, a negative electrode sheet, and a separator, wherein the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer arranged on at least one surface of the negative electrode current collector. The infiltration effect of the electrolyte on the electrode sheet has a great influence on the energy conversion efficiency of the battery monomer, so how to improve the infiltration effect of the battery monomer is also one of the problems in the field.

[0070] The applicant found that during the cycle use of the battery monomer, the electrolyte will accumulate at the bottom of the shell due to the action of gravity, resulting in that the electrolyte is more fully infiltrated into the electrode assembly located at the bottom, and the electrolyte is less infiltrated into the electrode assembly far from the bottom, and the infiltration performance of the electrolyte on the whole electrode assembly is not uniform; during the charge and discharge cycle of the battery monomer, when the active ions such as lithium ions migrate in the electrode assembly far from the bottom, the lithium ions may not be able to be embedded into the negative electrode sheet due to the lack of electrolyte, so that the lithium ions are deposited on the surface of the negative electrode sheet as metallic lithium, which on the one hand will cause the capacity of the battery monomer to decrease significantly in the later cycle, and worsen the service life of the battery; on the other hand, the deposited metallic lithium is easy to develop into lithium dendrites, which may pierce the separator and cause the positive electrode sheet and the negative electrode sheet to be short-circuited, affecting the service life of the battery.

[0071] Based on this, the present application provides a battery monomer, which includes a shell and an electrode assembly, the shell includes a top wall and a bottom wall arranged opposite to the top wall along a first direction, the bottom wall is used to support the electrode assembly; the electrode assembly includes a separator, the separator includes a base film and a first ceramic film layer arranged in a stack with the base film, a first groove is opened on the side of the first ceramic film layer away from the base film, the extension direction of the first groove intersects with the plane where the top wall is located or the plane where the bottom wall is located, and the sidewall of the first groove is composed of the first ceramic film layer, and the bottom wall of the first groove is composed of the first ceramic film layer or the base film.

[0072] In the present application, the battery monomer comprises a first ceramic film layer. A first groove is formed on the side of the first ceramic film layer away from the base film. Thus, the liquid guiding function of the first groove can be used to guide the electrolyte deposited at the bottom of the shell upward, thereby reducing the performance decline of the upper battery monomer due to insufficient electrolyte infiltration, and prolonging the service life of the battery monomer. Further, since the sidewall of the first groove is composed of the first ceramic film layer, the volume of the first ceramic film layer changes little with temperature, thereby maintaining the stability of the structure of the first groove, and thereby facilitating the full play of the liquid guiding function of the first groove. Therefore, the battery monomer disclosed in the present application has a prolonged service life.

[0073] The battery monomer and the battery device provided by the embodiments of the present application can be used in, but are not limited to, electric devices such as vehicles, ships or aircraft. For example, mobile phones, portable devices, notebook computers, electric vehicles, electric toys, electric tools, vehicles, ships and spacecraft, etc. For example, the spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc.

[0074] The embodiments of the present application also provide a battery device. The battery device can comprise one or more battery monomers provided by the embodiments of the present application. When there are multiple battery monomers, the multiple battery monomers are connected in series, in parallel or in a mixed manner through a current collecting component. Since the battery monomer provided by the embodiments of the present application has a prolonged service life, the battery device containing the battery monomer also has a prolonged service life.

[0075] In some embodiments of the present application, the battery can be a battery module to provide higher voltage and capacity. When there are multiple battery monomers, the multiple battery monomers are arranged and fixed to form a battery module.

[0076] In some embodiments of the present application, the battery can be a battery pack. The battery pack comprises a battery box and a battery monomer. The battery monomer or the battery module is contained in the battery box.

[0077] In some embodiments of the present application, the battery box can be part of the chassis structure of the vehicle. For example, part of the battery box can be at least part of the floor of the vehicle, or part of the battery box can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0078] The embodiments of the present application provide a power storage device. The power storage device comprises the battery monomer provided by the embodiments of the present application. Since the battery monomer provided by the embodiments of the present application has a prolonged service life, the power storage device containing the battery monomer also has a prolonged service life.

[0079] The power storage device provided by the embodiments of the present application can be, but is not limited to, a power storage container, a power storage cabinet, etc.

[0080] The application provides a power consumption device, which comprises the battery monomer provided by the application. Since the battery monomer provided by the application has a prolonged service life, the power consumption device comprising the battery monomer also has a prolonged service life.

[0081] The power consumption device provided by the application can be, but is not limited to, a mobile phone, a tablet computer, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric automobile, a ship, a spacecraft and the like.

[0082] In the following embodiments, the power consumption device provided by an embodiment of the application is taken as a vehicle 1000 for example for the convenience of description. The following is described in combination with the drawings.

[0083] Figure 1 The structural schematic diagram of the vehicle 1000 provided by some embodiments of the application is shown.

[0084] The vehicle 1000 can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range extended automobile and the like. As shown in the figure, Figure 1 The vehicle 1000 is internally provided with a battery 100, which can be arranged at the bottom, the head or the tail of the vehicle 1000. The battery 100 can be used for power supply of the vehicle 1000, for example, the battery 100 can be used as an operating power supply of the vehicle 1000. The vehicle 1000 can further comprise a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the working power demand of the vehicle 1000 during starting, navigation and driving.

[0085] In some embodiments of the application, the battery 100 can not only be used as an operating power supply of the vehicle 1000, but also be used as a driving power supply of the vehicle 1000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1000.

[0086] Figure 2 The exploded schematic diagram of the battery 100 provided by the application is shown.

[0087] As shown in the figure, Figure 2 The battery 100 comprises a battery box 10 and at least one battery monomer 20, and the battery box 10 is internally provided with an accommodating space, and the at least one battery monomer 20 is accommodated in the accommodating space.

[0088] In some embodiments of the application, the battery box 10 comprises a box body 102 and a box cover 101, and the box cover 101 covers the box body 102, so as to form the accommodating space between the box body 102 and the box cover 101.

[0089] The box body 102 can be a hollow structure with a top wall at one end, and the box cover 101 can be a plate-shaped structure, which is covered on the top wall side of the box body 102 to jointly define a containing space with the box body 102. Alternatively, the box cover 101 and the box body 102 can both be hollow structures with a top wall at one side, and the top wall side of the box cover 101 is covered on the top wall side of the box body 102. Of course, the battery box 10 formed by the box cover 101 and the box body 102 can have various shapes, such as a columnar shape, a square shape, etc.

[0090] The battery cell 20 refers to the smallest unit constituting a battery. In the battery 100, the battery cell 20 can be multiple, and the multiple battery cells 20 can be connected in series, in parallel, or in a mixed manner. The mixed manner refers to that the multiple battery cells 20 are connected in series and in parallel. The multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed manner, and then the whole formed by the multiple battery cells 20 is placed in the containing space formed by the box body 102 and the box cover 101. Of course, the battery 100 can also be that the multiple battery cells 20 are connected in series, in parallel, or in a mixed manner to form a battery module, and then the multiple battery modules are connected in series, in parallel, or in a mixed manner to form a whole, which is contained in the containing space formed by the box body 102 and the box cover 101. The battery 100 can further include other structures, for example, the battery 100 can further include a current combing component for realizing electrical connection between the multiple battery cells 20.

[0091] In the embodiments of the present application, the battery cell 20 can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging.

[0092] The battery cell 20 can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present application are not limited thereto.

[0093] In the present application, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell, or a battery cell with other shapes. The prismatic battery cell includes a square battery cell, a blade-shaped battery cell, and a multi-prismatic battery cell, such as a hexagonal battery cell, etc., and the present application is not particularly limited.

[0094] Electrode assembly 22 is the component in the battery cell 20 where the electrochemical reaction occurs. The casing 21 may contain one or more electrode assemblies 22. Electrode assembly 22 mainly consists of a positive electrode and a negative electrode, and typically a separator 223 is provided between the positive electrode 224 and the negative electrode 221. The portions of the positive electrode 224 and the negative electrode 221 containing active material constitute the main body of the electrode assembly, while the portion of the positive electrode 224 without positive active material constitutes the positive electrode tab 225. The portion of the negative electrode 221 without negative active material constitutes the negative electrode tab 222. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte. The positive electrode tab 225 connects to the positive electrode terminal 23, and the negative electrode tab 222 connects to the negative electrode terminal 24 to form a current loop.

[0095] The following reference Figures 3 to 10 Some embodiments of this application will be described in detail.

[0096] Figure 3 An exploded perspective view of a battery cell provided for some embodiments of this application; Figure 4 for Figure 3 A cross-sectional view of one of the electrode components on the aa' plane; Figure 5 Perspective views of electrode assemblies provided for other embodiments of this application; Figure 6 Perspective view of the isolation element provided for some embodiments of this application;

[0097] Figure 7 A cross-sectional schematic view of the spacer in the YZ plane for some embodiments of this application; Figure 8 A cross-sectional schematic view of the spacer in the XY plane for some embodiments of this application; Figure 9 for Figure 8 An enlarged view of region A in the provided isolation component; Figure 10 A perspective view of the isolation element provided for some other embodiments of this application.

[0098] like Figure 3 As shown, the battery cell 20 includes a housing 21 and at least one electrode assembly 22. The housing 21 is used to encapsulate the electrode assembly 22 and components such as electrolyte. The housing 21 can be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0099] like Figure 3 As shown, in some embodiments, the housing 21 includes a shell 211 and a cover 212. The shell 211 has a receiving cavity and a top wall in the first direction Z, and components such as the electrode assembly 22 and electrolyte are received within the receiving cavity of the shell.

[0100] likeFigure 3 As shown, the outer casing 21 also includes a cover 212 that closes the opening of the casing 211, forming a sealed space together with the casing 211 for accommodating components such as the electrode assembly 22 and the electrolyte.

[0101] like Figure 3 As shown, in some embodiments, the battery cell 20 further includes a positive electrode terminal 23, a negative electrode terminal 24, and a pressure relief structure 25. The positive electrode terminal 23, negative electrode terminal 24, and pressure relief structure 25 are all mounted on the cover 212. The positive electrode terminal 23 and negative electrode terminal 24 are both used for electrical connection with the electrode assembly 22 to output the electrical energy generated by the electrode assembly 22. The pressure relief structure 25 is used to release the internal pressure of the battery cell 20 when the internal pressure or temperature reaches a predetermined value. The pressure relief structure 25 can be a component such as an explosion-proof valve, explosion-proof disc, gas valve, pressure relief valve, or safety valve, but is not limited to these.

[0102] This application does not specifically limit the positions of the positive electrode terminal 23, the negative electrode terminal 24, and the pressure relief structure 25 in its embodiments. For example, Figure 3 As shown, in some embodiments, the pressure relief structure 25 is located between the positive electrode terminal 23 and the negative electrode terminal 24. Of course, in other embodiments, the positive electrode terminal 23 is located between the pressure relief structure 25 and the negative electrode terminal 24, or the negative electrode terminal 24 is located between the pressure relief structure 25 and the positive electrode terminal 23.

[0103] In some embodiments, the housing includes a casing and a cover, the casing having an opening, the cover closing the opening, and the cover forming a top wall. The battery cell has an extended service life.

[0104] In some embodiments, the housing includes a casing and a cover, the casing having an opening, the cover closing the opening, and the cover forming a bottom wall. The battery cell has an extended service life.

[0105] In some embodiments, the housing includes a casing and a cover. The casing includes two first sides and two second sides disposed opposite to each other, the first sides and the second sides forming an opening. The cover closes the opening. One first side forms a bottom wall, and the other first side forms a top wall. This battery cell has an extended service life.

[0106] In some embodiments, the area of ​​the first side is smaller than the area of ​​the second side. This results in an extended battery cell lifespan.

[0107] like Figure 3 As shown, the battery cell 20 also includes an electrode assembly 22 and an electrolyte (not shown in the figure). The electrode assembly 22 and the electrolyte are both contained within the sealed space formed by the cover 212 and the shell 211.

[0108] In some embodiments, the electrolyte includes an electrolyte salt and a solvent. In some embodiments, the electrolyte salt can be selected from at least one of sodium hexafluorophosphate, sodium tetrafluoroborate, sodium perchlorate, sodium hexafluoroarsenate, sodium bisfluorosulfonylimide, sodium bis-trifluoromethylsulfonylimide, sodium trifluoromethanesulfonate, sodium difluorophosphate, sodium difluoroboric oxalate, sodium boric oxalate, sodium difluorophosphoric oxalate, and sodium tetrafluorophosphoric oxalate. The solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butyrosulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0109] The electrode assembly 22 serves as a core component of the battery cell 20 to generate electric energy. Referring to Figure 4 and Figure 5 , the electrode assembly 22 includes a positive electrode tab 224 and a negative electrode tab 221.

[0110] In the present application, the positive electrode tab 224 includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector. The positive electrode current collector has two opposite surfaces in the thickness direction thereof, and the positive electrode film layer is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0111] In some embodiments, the positive electrode current collector can employ a metal foil or a composite current collector. For example, as the metal foil, an aluminum foil can be employed. The composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer.

[0112] In some embodiments, when the battery cell is a lithium ion battery, the positive electrode active material can employ a positive electrode active material known in the art for a lithium ion battery. As an example, the positive electrode active material can include at least one of a lithium-containing phosphate of olivine structure, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials.

[0113] In some embodiments, when the battery cell is a sodium ion battery, the positive electrode active material can employ a positive electrode active material known in the art for a sodium ion battery. As an example, the positive electrode active material can include at least one of a sodium-containing layered oxide, a polyanion sodium ion compound, and a prussian blue sodium ion compound. The sodium-containing layered oxide can be an iron-manganese-based layered oxide. The iron-manganese-based layered oxide includes at least one of a nickel-iron-manganese-based layered oxide and a copper-iron-manganese-based layered oxide.

[0114] In the present application, the negative electrode tab includes a negative current collector and a negative film layer disposed on at least one surface of the negative current collector, and the negative film layer includes a negative active material. The negative current collector has two opposite surfaces in the thickness direction of the negative current collector, and the negative film layer is disposed on any one or both of the two opposite surfaces of the negative current collector.

[0115] In some embodiments, the negative current collector can adopt a metal foil or a composite current collector. For example, as a metal foil, a copper foil can be adopted.

[0116] In some embodiments, the negative active material can adopt a negative active material for a battery known in the art. As an example, the negative active material can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, and lithium titanate, etc.

[0117] Referring to Figure 4 and Figure 5 In the present application, the electrode assembly 22 further includes a separator 223 disposed between the positive electrode tab 224 and the negative electrode tab 221, which mainly functions to prevent the positive electrode tab 224 and the negative electrode tab 221 from short-circuiting while allowing ions to pass through.

[0118] Continuing to refer to Figure 4 In some embodiments, the stack formed by the positive electrode tab 224, the separator 223, and the negative electrode tab 221 is wound along a winding axis, and the winding axis is parallel to the first direction. In the above battery cell, since the electrode tabs (positive electrode tab, negative electrode tab) are in a crimped state, the space waste of the electrode assembly is reduced, which is conducive to achieving a high volumetric energy density of the battery cell. In addition, the design of the first groove is conducive to the more effective penetration of the electrolyte into the inner layer of the crimped electrode tab, so that the battery cell has a long service life while taking into account the high volumetric energy density.

[0119] Continuing to refer to Figure 5 In some embodiments, the positive electrode tab 224, the separator 223, and the negative electrode tab 221 are arranged in sequence. Such a design is conducive to prolonging the service life of the battery cell.

[0120] The separator 203 provided by the embodiments of the present application will be further described below in combination with specific drawings.

[0121] Referring to Figures 6-10 The separator 223 includes a base film 1 and a first ceramic film layer 2 stacked with the base film 1. At least one first groove 1a is formed at the end of the side of the first ceramic film layer 2 away from the base film 1, the side wall of the first groove 1a is formed by the first ceramic film layer 2, and the bottom wall of the first groove 1a is formed by the first ceramic film layer 2 or the base film 1.

[0122] In the present application, the base membrane refers to a bottom film that plays a supporting and protective role in the battery monomer separator. It can allow the electrolyte to permeate, while isolating the positive and negative materials to prevent them from directly contacting and causing short circuit. The physical and chemical properties of the base membrane have an important influence on the performance and safety of the battery.

[0123] The material of the base membrane is not specifically limited in the embodiments of the present application. For example, the material of the base membrane includes one or more of polyethylene, polypropylene, non-woven fabric, polyimide, polytetrafluoroethylene, polytetrafluoroethylene non-woven fabric, polyvinyl chloride or polyvinyl chloride non-woven fabric. The base membrane using the above-mentioned material has the advantages of low cost, stable chemical properties, excellent mechanical properties, etc., which is beneficial to improve the chemical stability and mechanical properties of the separator.

[0124] The thickness of the base membrane is not specifically limited in the embodiments of the present application, and the thickness of the base membrane known in the art can be used. In some embodiments, the thickness of the base membrane is 5-15 μm, for example, the thickness of the base membrane is 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm or a value between any two values. The thickness of the base membrane in the above range makes the separator have suitable mechanical stability and chemical stability, which is beneficial to balance the high safety performance and low internal resistance of the battery.

[0125] In the present application, the first ceramic film layer 2 is attached to the surface of the base membrane 1 and plays a protective role for the base membrane. The thickness of the first ceramic film layer is not specifically limited in the embodiments of the present application, and the thickness of the ceramic film layer known in the art can be used. In some embodiments, the thickness of the first ceramic film layer 2 is 1-15 μm, for example, the thickness of the first ceramic film layer is 1 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm or a value between any two values.

[0126] In the present application, at least one first groove 1a is provided on the side of the first ceramic film layer 2 away from the base membrane 1, and the side wall of the first groove is composed of the first ceramic film layer, i.e. the first ceramic film layer 2 is a continuous film layer.

[0127] In some embodiments, the bottom wall and the side wall of the first groove 1a are both composed of the first ceramic film layer. Since the side wall and the bottom wall of the first groove are both composed of the first ceramic film layer, i.e. there is a first ceramic film layer between the bottom wall of the first groove and the base membrane, the volume of the first ceramic film layer changes little with temperature, which can inhibit the expansion and contraction of the volume of the base membrane, thereby maintaining the stability of the first groove structure, and further facilitating the first groove to fully play its liquid guiding function. Therefore, the battery monomer disclosed in the present application has a prolonged service life.

[0128] In some embodiments, the first recess 1a has a distance between the two ends in the second direction that is less than the size of the first ceramic film layer in the second direction, so that the side wall and the bottom wall of the first recess 1a are both formed by the first ceramic film layer 2.

[0129] In the present application, the extension direction of the first recess 1a intersects the plane in which the top wall is located or the plane in which the bottom wall is located. Such a structure design enables the first recess 1a to extend along the first direction (i.e., the height direction). This extension design enables the first recess to guide the electrolyte deposited on the bottom of the shell upward, ensuring that the electrolyte can reach the top area of the battery cell, thereby reducing the performance degradation of the upper battery cell caused by insufficient electrolyte infiltration, and further helping to prolong the service life of the battery cell.

[0130] In some embodiments, the first recess 1a extends to one end of the first ceramic film layer near the top wall side in the first direction. Such a design helps the first recess to guide the electrolyte to the top of the battery cell, promoting the uniform distribution of the electrolyte inside the battery cell, thereby reducing the performance degradation of the upper battery cell caused by insufficient electrolyte infiltration, and prolonging the service life of the battery cell.

[0131] In some embodiments, the first recess 1a extends to one end of the first ceramic film layer 2 near the bottom wall side in the first direction. Such a design helps to guide the electrolyte deposited on the bottom of the shell upward, thereby reducing the risk of the battery caused by insufficient electrolyte, and prolonging the service life of the battery.

[0132] In some embodiments, the first recess extends to both ends of the first ceramic film layer in the first direction. Thus, it is beneficial to prolong the service life of the battery cell.

[0133] The number of first recesses 1a is not specifically limited in the embodiments of the present application, and the number of first recesses 1a can be set as needed. For example, the number of first recesses 1a can be 2, 4, 6, 8, 10, 100, 200, 500, 1000, or any number between any two values.

[0134] Referring to Figure 7 In some embodiments, the spacer 223 further includes a second recess 2a that intersects and communicates with the first recess 1a. By providing the second recess 2a that communicates with the first recess 1a, it is beneficial to increase the transmission path of the electrolyte and improve the infiltration effect of the battery cell, thereby further prolonging the service life of the battery cell.

[0135] The number of second recesses 2a is not specifically limited in the embodiments of the present application, and the number of second recesses 2a can be set as needed. For example, the number of second recesses 2a can be 2, 4, 6, 8, 10, 100, 200, 500, 1000, or any number between any two values.

[0136] In some embodiments, the first recess has a central axis that forms an angle with the first direction Z that is greater than or equal to 0 degree and less than 90 degrees. For example, the first recess has a central axis that forms an angle with the first direction that is 0 degree, 1 degree, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, or a value between any two of the values. Optionally, the first recess has a central axis that forms an angle with the first direction that is 30 degrees to 60 degrees. By setting the angle of the central axis of the first recess with the first direction in the above range, it is beneficial to guide the electrolyte at the bottom of the shell upwards, preventing the electrolyte from being unable to replenish the upper layer of the battery cell in time due to gravity during circulation. In particular, when the angle of the first direction is greater than 0 degrees, on the one hand, it is beneficial to allow the electrolyte to climb upwards through the first recess to soak more pole pieces. On the other hand, it is beneficial to reduce the resistance that the electrolyte needs to overcome when climbing, making it easier for the electrolyte to climb. Therefore, by setting the angle of the central axis of the first recess with the first direction in the above range, it is beneficial to further improve the wettability of the battery cell, thereby further prolonging the service life of the battery cell.

[0137] In some embodiments, the first recess has a cross-sectional area in a plane perpendicular to the first direction of 0.001 mm 2 to 0.24 mm 2 . The first plane is perpendicular to the first direction. For example, the first recess has a cross-sectional area in a plane perpendicular to the first direction of 0.001 mm 2 , 0.005 mm 2 , 0.01 mm 2 , 0.015 mm 2 , 0.02 mm 2 , 0.025 mm 2 , 0.03 mm 2 , 0.04 mm 2 , 0.06 mm 2 , 0.08 mm 2 , 0.1 mm 2 , 0.12 mm 2 , 0.14 mm 2 , 0.16 mm 2 , 0.18 mm 2 , 0.20 mm 2 , 0.22 mm 2 , 0.24 mm 2 , or a value between any two of the values. Optionally, the first recess has a cross-sectional area in a plane perpendicular to the first direction of 0.01 mm 2 to 0.24 mm 2 , 0.015 mm2 0.24mm 2 By controlling the cross-sectional area of the first groove in the first plane within the above range, the first groove is facilitated to achieve capillary action, increase the flow speed of the electrolyte in the first groove, thereby improving the soaking effect of the battery monomer and prolonging the service life of the battery monomer.

[0138] In some embodiments, the ratio of the total area of the first groove projected on the first surface to the area of the first surface is 3% to 71%. For example, the ratio of the total area of the first groove projected on the first surface to the area of the first surface is 3%, 17%, 20%, 33%, 49%, 50%, 60%, 70%, or a value between any two of the values. Alternatively, the ratio of the total area of the first groove projected on the first surface to the area of the first surface is 17% to 71%, and alternatively, the ratio of the total area of the first groove projected on the first surface to the area of the first surface is 20% to 50%. By controlling the ratio of the total area of the first groove projected on the first surface to the area of the first surface within the above range, on the one hand, it is beneficial to maintain high mechanical strength of the separator, thereby prolonging the service life of the battery monomer. On the other hand, it is beneficial to fully exert the liquid guiding function of the first groove, thereby further prolonging the service life of the battery monomer.

[0139] Referring to FIGS. 8 and Figure 9 In some embodiments, the size H of the first groove 1a in the second direction is smaller than the size a of the first groove 1a in the third direction Y, the second direction being the stacking direction of the base film 1 and the first ceramic film layer 2, and the first direction, the second direction, and the third direction being perpendicular to each other. By the above arrangement, the first groove is facilitated to be formed.

[0140] Referring to FIGS. 8 and Figure 9 In some embodiments, the size H of the first groove in the second direction is 0.1 μm to 8 μm. For example, the size H of the first groove in the second direction is 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, or a value between any two of the values. Alternatively, the size H of the first groove in the second direction is 0.5 μm to 8 μm. By setting the size of the first groove in the second direction within the above range, the first groove is facilitated to achieve capillary action, thereby increasing the flow speed of the electrolyte in the first groove, improving the soaking effect of the electrolyte on the electrode sheet, and prolonging the service life of the battery monomer.

[0141] Referring to FIGS. 8 and Figure 9In some embodiments, the first groove has a dimension a in the third direction of 1 mm to 30 mm. For example, the first groove has a dimension a in the third direction of 1 mm, 3 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, or a value between any two of the values. Alternatively, the first groove has a dimension a in the third direction of 3 mm to 30 mm. The dimension a in the third direction of the first groove is moderate, which is conducive to the capillary action of the first groove and the full play of the liquid guiding function of the first groove, thereby further prolonging the service life of the battery cell.

[0142] Referring to Figure 9 In some embodiments, the distance L between the center axes of two adjacent first grooves is 6 mm to 60 mm. For example, the distance L between the center axes of two adjacent first grooves is 6 mm, 7 mm, 10 mm, 20 mm, 30 mm, 35 mm, 40 mm, 50 mm, 60 mm, or a value between any two of the values. Alternatively, the distance L between the center axes of two adjacent first grooves is 10 mm to 50 mm. Alternatively, the distance L between the center axes of two adjacent first grooves is 15 mm to 30 mm. The distance L between the center axes of two adjacent first grooves is moderate, which is conducive to the full play of the liquid guiding function and the high mechanical strength of the spacer.

[0143] In the present application, the dimension H of the first groove in the second direction, the dimension a of the first groove in the third direction, and the distance L between the center axes of two adjacent first grooves can be tested by ion polishing cross-section morphology (CP) of the spacer using a cross-section polisher. Specifically, the battery is disassembled to obtain the spacer. The spacer is fixed on a sample table; the sample table is locked and fixed on a sample holder, the power of the argon ion cross-section polisher (for example, the IB-09010CP argon ion cross-section polisher of Japan JEOL Company) is turned on and vacuumized (for example, 10 -7 Pa), the argon flow rate (for example, 0.12 MPa) and the polishing time (for example, 90 min) are set, and the sample table is adjusted to the swing mode to start polishing. After polishing is completed, the SEM photo of the cross-section is collected by a scanning electron microscope (SEM), and then the H, a, and L data can be obtained according to the scale of the SEM photo.

[0144] In some embodiments, the first ceramic film layer comprises ceramic particles. The ceramic particles have high thermal stability. The use of the first ceramic film layer comprising ceramic particles is conducive to further inhibiting the volume expansion and contraction of the base film, thereby maintaining the structural stability of the first groove and promoting the first groove to fully play its liquid guiding function, thereby prolonging the service life of the battery cell.

[0145] In some embodiments, the ceramic particles comprise first particles and / or second particles, the volume average particle size Dv50 of the first particles is 0.1 μm to 2 μm; and the volume average particle size Dv50 of the second particles is greater than 2 μm and less than or equal to 5 μm. For example, the volume average particle size Dv50 of the first particles is 0.1 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.5 μm, 2 μm, or a value between any two of the values. For example, the volume average particle size Dv50 of the second particles is 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3 μm, 4 μm, 5 μm, or a value between any two of the values.

[0146] In some embodiments, the ceramic particles comprise first particles and second particles. By using first particles and second particles of different particle sizes, the smaller volume first particles can be filled between the larger volume second particles, thereby forming gaps between the first particles and the second particles, which can serve as flow channels for the electrolyte, facilitating the uniform distribution of the electrolyte inside the battery, thereby prolonging the service life of the battery cell.

[0147] In this application, the volume distribution particle size Dv50 of a material represents the particle size corresponding to the cumulative volume distribution percentage of 50%, which can be measured by instruments and methods known in the art. For example, GB / T 19077-2016 can be referred to, and a laser particle size analyzer can be used for measurement. The test instrument can be a Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd., UK.

[0148] In some embodiments, the ceramic particles comprise at least one of aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, tin dioxide, boehmite, magnesium oxide, zinc oxide, barium sulfate, magnesium nitride, or barium titanate. The above-mentioned materials have the advantages of good flame retardant effect, good chemical stability, good thermal stability, etc. The use of ceramic particles comprising the above-mentioned materials is conducive to further improving the thermal stability of the battery cell.

[0149] In some embodiments, the first ceramic film layer is laminated on both side surfaces of the base film 1, i.e., the base film is provided with a first ceramic film layer on both side surfaces in the stacking direction. Such a design is conducive to further improving the service life of the battery cell.

[0150] Of course, in some embodiments, the first ceramic film layer 2 is laminated on one side surface of the base film 1.

[0151] For example, in some embodiments, the first ceramic film layer 2 is arranged on the side of the base film 1 facing the negative electrode tab 221, and the surface of the base film 1 away from the first ceramic film layer 2 is in contact with the positive electrode tab. In this embodiment, the first ceramic film layer 2 is arranged on the side facing the negative electrode tab, which is conducive to improving the probability of contact of the negative electrode tab with the electrolyte, thereby reducing the abnormality of the negative electrode tab interface caused by poor electrolyte infiltration, and further prolonging the service life of the battery cell.

[0152] In some embodiments, the first ceramic film layer 2 is arranged on the side of the base film 1 facing the positive electrode tab, and the surface of the base film 1 away from the first ceramic film layer 2 is in contact with the negative electrode tab. Such design is helpful for the rapid transmission of active ions in the electrolyte to the positive electrode tab, thereby improving the charge and discharge speed of the battery and prolonging the service life of the battery cell.

[0153] Referring to Figure 10 In the embodiment in which the first ceramic film layer 2 is laminated on one side surface of the base film 1, the spacer further comprises a liquid guiding layer 3 laminated on the surface of the base film 1 away from the first ceramic film layer 1, wherein a groove is formed on the side of the liquid guiding layer away from the base film. By forming a groove on the side of the liquid guiding layer away from the base film, the flow channel of the electrolyte is increased, thereby further improving the infiltration performance of the battery cell and prolonging the service life of the battery cell.

[0154] In some embodiments, the liquid guiding layer comprises a second ceramic film layer, a third groove is formed on the side of the second ceramic film layer away from the base film, and the side wall of the third groove is formed by the second ceramic film layer and the bottom wall of the third groove is formed by the base film, that is, the second ceramic film layer is a discontinuous film layer. The material of the second ceramic film layer can refer to the material of the first ceramic film layer described above, which will not be repeated here. In this embodiment, by forming a third groove on the side of the second ceramic film layer away from the base film, the flow channel of the electrolyte is increased, thereby further improving the infiltration performance of the battery cell and prolonging the service life of the battery cell.

[0155] In some embodiments, the liquid guiding layer comprises a bonding layer, and a fourth groove is formed on the side of the bonding layer away from the base film, and the side wall of the fourth groove is formed by the bonding layer. That is, the bonding layer is a continuous film layer.

[0156] In some embodiments, a fourth groove is formed on the side of the bonding layer away from the base film, the bottom wall of the fourth groove is formed by the base film, and the side wall of the fourth groove is formed by the bonding layer, that is, the bonding layer is a discontinuous film layer.

[0157] In the embodiment in which the liquid guiding layer comprises the adhesive layer, the flow channel of the electrolyte is increased by opening the fourth groove on the side of the adhesive layer away from the base film, thereby further improving the wetting performance of the battery monomer and prolonging the service life of the battery monomer.

[0158] The material of the adhesive layer is not specifically limited in the embodiments of the present application, and any material that can achieve an adhesive force between the adhesive layer and the pole piece greater than the adhesive force between the first ceramic film layer and the pole piece can be used. For example, the adhesive layer can comprise one or more of polytetrafluoroethylene, butyl rubber latex, polyimide, polyacrylonitrile, polyamide, polyamide acid, and polytetrafluoroethylene.

[0159] In some embodiments, the separator further comprises a functional layer stacked on the surface of the base film away from the first ceramic film layer, and the relative proportion of the reduction in the thermal shrinkage rate of the composite of the functional layer and the base film to the thermal shrinkage rate of the base film is greater than 10%. Such a design is conducive to further inhibiting the thermal shrinkage of the base film and improving the structural stability of the separator, thereby prolonging the service life of the battery monomer.

[0160] In the present application, the commonly used thermal shrinkage test method in the art can be used. Specifically, a 100 mm x 100 mm sample is placed flat in an oven at (150 ± 1) °C for 60 min, and then removed. The length of the longitudinal and transverse lines is measured, and the thermal shrinkage rates in the longitudinal and transverse directions are calculated, respectively, thermal shrinkage rate = (L0-L1) / L0, where L1 is the length after thermal shrinkage, and L0 is the initial length (100 mm in this case).

[0161] In some embodiments, the separator further comprises a functional layer, and the adhesive force between the functional layer and the positive or negative pole piece is greater than the adhesive force between the base film and the positive or negative pole piece. The provision of the functional layer is conducive to improving the structural stability of the separator, thereby prolonging the service life of the battery monomer.

[0162] In a specific embodiment, the battery monomer comprises: a housing and an electrode assembly, the housing forms an accommodation cavity inside, and the accommodation cavity has a top wall in a first direction; and the electrode assembly is arranged in the accommodation cavity. The electrode assembly comprises a positive pole piece, a separator and a negative pole piece arranged in sequence in a second direction. As shown in Figure 6 As shown in FIG. 1, the separator 223 comprises a base film 1 and a first ceramic film layer 2 stacked on the base film 1, and at least one first groove 1a is opened at the end of the side of the first ceramic film layer 2 away from the base film 1.

[0163] Embodiments

[0164] Hereinafter, the examples of the present application will be described. The examples described below are illustrative and are intended to be purely exemplary of the application and are not intended to limit the application. Unless otherwise indicated, technical or conditions not specified in the examples are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained commercially.

[0165] Example 1

[0166] Preparation of battery cells

[0167] (1) Preparation of the separator

[0168] A 7-μm polyethylene film was used as the base film, boehmite slurry (ceramic particles) was mixed in water to form a ceramic slurry, and the ceramic slurry was coated on the first surface of the base film using a gravure roll at a speed of 30 m / min and a coating thickness of 3 μm. After coating was completed, drying was performed inside an oven, and the oven temperature was 70°C.

[0169] Subsequently, a PVDF slurry dissolved in NMP solvent was coated on the second surface of the base film away from the first surface, and the coating thickness was 2 μm. After coating was completed, drying was performed inside an oven, and the oven temperature was 70°C, to obtain the separator. The separator included the base film, the first surface of the base film was attached with the first ceramic film layer, and the parameters of the first ceramic film layer are shown in Table 1-1. The second surface of the base film was attached with the functional layer. The parameters of the functional layer are shown in Table 1-2.

[0170] (2) Preparation of the positive electrode sheet:

[0171] Lithium iron phosphate (LiFePO4), conductive carbon black, and polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 97.2:1:1.8, and then a solvent N-methyl pyrrolidone was added, and stirring was performed until uniformity was achieved, to obtain a positive electrode slurry. The positive electrode slurry was coated on both surfaces of an aluminum foil, and after drying, cold pressing, die cutting, and slitting, a positive electrode sheet was obtained.

[0172] (3) Preparation of the negative electrode sheet:

[0173] Graphite, conductive carbon black, styrene-butadiene rubber (SBR), and carboxymethyl cellulose were mixed in a mass ratio of 97.7:0.7:1:0.6, and then water was added, and stirring was performed until uniformity was achieved, to obtain a negative electrode slurry. The negative electrode slurry was coated on both surfaces of a negative electrode current collector copper foil, and after drying and cold pressing, a negative electrode sheet was obtained.

[0174] (4) Preparation of the electrolyte:

[0175] Vinyl carbonate, diethyl carbonate, dimethyl carbonate are mixed in a volume ratio of 1:1:1 to obtain a mixed solvent, then the fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0176] (5) Assembly of the battery monomer:

[0177] The negative electrode sheet, the separator, and the positive electrode sheet are placed in order, with the separator between the negative electrode sheet and the positive electrode sheet to serve as a separation function. Then the electrode assembly is obtained by winding and welding the tabs, and the electrode assembly is placed in an aluminum shell to inject electrolyte, and after packaging, standing, formation, and capacity, a lithium ion battery monomer is prepared.

[0178] Example 2

[0179] The battery monomer is prepared in the same manner as in Example 1, except that:

[0180] A 7-μm polyethylene film is used as the base film, boehmite slurry and PVDF are mixed in water to form a ceramic slurry (boehmite slurry and PVDF mass ratio of 75:25), and a gravure roller is used to coat the ceramic slurry on the first surface and the second surface of the base film, with a speed of 30 m / min and a coating thickness of 3 μm during the coating process. After coating, drying is performed in an oven with a temperature of 70°C to obtain the separator, which includes a base film, a first ceramic film layer attached to the first surface of the base film, and a liquid guiding layer (second ceramic film layer) attached to the second surface of the base film. The parameters of the first ceramic film layer are shown in Table 1-1, and the parameters of the second ceramic film layer and the third groove are shown in Table 1-2.

[0181] Example 3

[0182] The battery monomer is prepared in the same manner as in Example 1, except that:

[0183] (1) Preparation of the separator:

[0184] A 7-μm polyethylene film is used as the base film, boehmite slurry is mixed in water to form a ceramic slurry, and a gravure roller is used to coat the ceramic slurry on the first surface of the base film, with a speed of 30 m / min and a coating thickness of 3 μm during the coating process. After coating, drying is performed in an oven with a temperature of 70°C.

[0185] Then, PVDF dissolved in N-methyl pyrrolidone (NMP) was coated on the second surface of the base film to form a slurry by using a gravure roll, and the coating thickness was 2 μm. After the coating was completed, drying was performed inside an oven, and the temperature of the oven was 70°C, to obtain a separator including the base film, the first surface of the base film attached to the first ceramic film layer, and the parameters of the first ceramic film layer are shown in Table 1-1. The second surface of the base film was attached to the liquid guiding layer (adhesion layer), and the side of the adhesion layer facing away from the base film was provided with a groove (fourth groove). The parameters of the adhesion layer and the fourth groove are shown in Table 1-2.

[0186] Example 4

[0187] The battery cell was prepared in the same manner as in Example 1, except that:

[0188] (1) Preparation of the separator: a 7 μm polyethylene film was used as the base film. The boehmite slurry and PVDF were mixed in water to form a ceramic slurry (the mass ratio of the boehmite slurry to PVDF was 75:25), and the ceramic slurry was coated on the first surface of the base film by using a gravure roll, and the speed used in the coating process was 30 m / min, and the coating thickness was completed, and drying was performed inside an oven, and the temperature of the oven was 70°C, to form the first ceramic film layer having the first groove on the surface of the first base film, to obtain the separator. The thickness h of the first ceramic film layer was 3 μm, and the parameters of the first groove are shown in Table 1-1.

[0189] Examples 5-23

[0190] The battery cell was prepared in the same manner as in Example 1, except that:

[0191] (1) In the step of preparation of the separator, the parameters of the first groove were adjusted according to Table 1-1.

[0192] Comparative Example 1

[0193] The battery cell was prepared in the same manner as in Example 1, except that: the surface of the first ceramic film layer was not formed with the first groove.

[0194] Table 1-1

[0195]

[0196]

[0197] In Table 1, " / " represents that the relevant item is not set. "h" represents the thickness of the first ceramic film layer; "H" represents the size of the first groove in the second direction (corresponding to the depth of the groove); "a" represents the size of the first groove in the third direction (corresponding to the width of the groove); "L" represents the spacing between the center axes of adjacent first grooves (corresponding to the spacing of the grooves); "σ" represents the ratio of the total area of the first grooves projected on the first surface to the area of the first surface; "S" represents the cross-sectional area of the first groove in the plane perpendicular to the first direction; and "γ" represents the included angle between the center axis of the first groove and the first direction.

[0198] Table 1-2

[0199]

[0200]

[0201] Performance testing of battery cells

[0202] (1) Test of cycle performance under 25 conditions:

[0203] ① Charge the battery monomer at 25°C high temperature condition to 40% state of charge (SOC) at 1.5C rate;

[0204] ② Then charge to 60% SOC at 1C rate;

[0205] ③ Then charge to 80% SOC at 0.8C rate;

[0206] ④ Finally charge to 100% SOC at 0.33C rate.

[0207] ⑤ Discharge to 0% SOC at 1C current constant current, record the first cycle discharge capacity D1;

[0208] ⑥ Cycle the above steps ① to ⑤, record the discharge capacity Dn when it reaches 80% D1, record the corresponding cycle number at this time, and the test results are recorded in Table 2.

[0209] (2) Test of cycle performance under 60°C high temperature condition:

[0210] ① Charge the battery monomer at 60°C high temperature condition to 40% SOC at 1.5C rate;

[0211] ② Then charge to 60% SOC at 1C rate;

[0212] ③ Then charge to 80% SOC at 0.8C rate;

[0213] ④ Finally charge to 100% SOC at 0.33C rate.

[0214] ⑤ with 1C current constant current discharge to 0% SOC, record the first circle of discharge capacity D1;

[0215] ⑥ cycle the above step ① to step ⑤, record the discharge capacity Dn reaches 80% D1, record the corresponding cycle number at this time, the test results are recorded in Table 2.

[0216] Table 2

[0217]

[0218]

[0219] The data in Table 2 can be seen: compared with Comparative Example 1 (the first ceramic film layer is not provided with the first groove). The side wall of the first groove in the battery monomer provided by Examples 1 to 23 is composed of the first ceramic film layer, the cycle performance of the battery monomer provided by Examples 1 to 23 is better than that of the battery monomer provided by Comparative Example 1, and the battery monomer provided by Examples 1 to 23 has a prolonged service life.

[0220] The above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, Comprising: a housing and an electrode assembly; the housing comprises a top wall and a bottom wall disposed opposite to the top wall in a first direction, the bottom wall is used to support the electrode assembly; the electrode assembly comprises a separator, the separator comprises a base film and a first ceramic film layer arranged in a stacked manner with the base film, a first groove is opened on a side of the first ceramic film layer away from the base film, an extension direction of the first groove intersects with a plane where the top wall is located or a plane where the bottom wall is located, and a side wall of the first groove is composed of the first ceramic film layer, and a bottom wall of the first groove is composed of the first ceramic film layer or the base film.

2. The battery cell of claim 1, wherein, The bottom wall of the first groove is composed of the first ceramic film layer.

3. The battery cell according to claim 1 or 2, characterized in that, The first groove extends to one end of the first ceramic film layer on the side close to the top wall in the first direction.

4. The battery cell according to any one of claims 1 to 3, characterized in that, The first groove extends to one end of the first ceramic film layer on the side close to the bottom wall in the first direction.

5. The battery cell according to any one of claims 1 to 4, characterized in that, The angle between the extension direction of the first groove and the first direction is greater than or equal to 0 degrees and less than 90 degrees.

6. The battery cell of any one of claims 1 to 5, wherein, The angle between the extension direction of the first groove and the first direction is 30 degrees to 60 degrees.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The first groove has a cross-sectional area in a plane perpendicular to the first direction of 0.001 mm 2 to 0.24 mm 2 .

8. The battery cell of any one of claims 1 to 7, wherein, The first groove has a cross-sectional area in a plane perpendicular to the first direction of 0.01mm 2 to 0.24mm 2 .

9. The battery cell of any one of claims 1 to 8, wherein, The ratio of the total area of the first groove projected on the first surface to the area of the first surface is 17% to 71%, and the first surface is the surface of the side of the first ceramic film layer facing the base film.

10. The battery cell of any one of claims 1 to 9, wherein, The ratio of the total area of the first groove projected on the first surface to the area of the first surface is 20% to 50%.

11. The battery cell of any one of claims 1 to 10, wherein, The size of the first groove in the second direction is smaller than the size of the first groove in the third direction, the second direction is the stacking direction of the base film and the first ceramic film layer, and the first direction, the second direction and the third direction are perpendicular to each other.

12. The battery cell of claim 11, wherein, The size of the first groove in the second direction is 0.1 μm to 8 μm.

13. The battery cell according to claim 11 or 12, characterized in that The size of the first groove in the second direction is 0.5 μm to 8 μm.

14. The battery cell of any one of claims 11 to 13, wherein, The size of the first groove in the third direction is 1 mm to 30 mm.

15. The battery cell of any one of claims 11 to 14, wherein, The size of the first groove in the third direction is 3 mm to 30 mm.

16. The battery cell of any one of claims 1 to 15, wherein, The spacing between the center axes of two adjacent first grooves is 10 mm to 60 mm.

17. The battery cell of any one of claims 1 to 16, wherein, The spacing between the center axes of two adjacent first grooves is 15 mm to 30 mm.

18. The battery cell of any one of claims 1-17, wherein, The first ceramic film layer comprises ceramic particles.

19. The battery cell of claim 18, wherein, The ceramic particles comprise first particles and / or second particles, The volume average particle size Dv50 of the first particles is 0.1 μm to 2 μm. The volume average particle size Dv50 of the second particles is greater than 2 μm and less than or equal to 5 μm.

20. The battery cell of claim 18 or 19, wherein, The ceramic particles comprise at least one of aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, tin dioxide, boehmite, magnesium oxide, zinc oxide, barium sulfate, magnesium nitride or barium titanate.

21. The battery cell of any one of claims 1-20, wherein, A second groove is also opened on the side of the first ceramic film layer away from the base film, the second groove intersects and communicates with the first groove.

22. The battery cell of any one of claims 1-21, wherein, The electrode assembly further comprises a positive electrode tab and a negative electrode tab, the first ceramic film layer is stacked on the side surface of the base film facing the positive electrode tab or the negative electrode tab.

23. The battery cell of claim 22, wherein, The positive electrode tab, the separator and the negative electrode tab are arranged in a stacked manner.

24. The battery cell of claim 22, wherein, The positive electrode sheet, the separator, and the negative electrode sheet are wound along a winding axis, and the winding axis is parallel to the first direction.

25. The battery cell of any one of claims 22-24, wherein, The separator further comprises a liquid guiding layer, the liquid guiding layer is laminated on the surface of the base film away from the first ceramic film layer, The liquid guiding layer comprises a second ceramic film layer, a third groove is formed on the side of the second ceramic film layer away from the base film, the sidewall of the third groove is composed of the second ceramic film layer, and the bottom wall of the third groove is composed of the base film or the second ceramic film layer. Alternatively, the liquid guiding layer comprises a bonding layer, a fourth groove is formed on the side of the bonding layer away from the base film, the sidewall of the fourth groove is composed of the bonding layer, and the bottom wall of the fourth groove is composed of the base film or the bonding layer.

26. The battery cell of any one of claims 22-24, wherein, The separator further comprises a functional layer, the functional layer is laminated on the surface of the base film away from the first ceramic film layer, and the functional layer satisfies at least one of the following conditions: The relative proportion of the reduction of the thermal shrinkage rate of the composite of the functional layer and the base film to the thermal shrinkage rate of the base film is greater than 10%; The bonding force between the functional layer and the positive electrode sheet or the negative electrode sheet after thermal pressing is greater than the bonding force between the base film and the positive electrode sheet or the negative electrode sheet after thermal pressing.

27. The battery cell of any one of claims 22-24, wherein, The surface of the base film away from the first ceramic film layer is in contact with the positive electrode sheet or the negative electrode sheet.

28. The battery cell of any one of claims 1-27, wherein, The housing comprises: a shell having an opening; a cover body closing the opening, and the cover body forms the top wall.

29. The battery cell of any one of claims 1-27, wherein, The housing comprises: a shell having an opening; a cover body closing the opening, and the cover body forms the bottom wall.

30. The battery cell of any one of claims 1-27, wherein, The housing comprises: a shell comprising two oppositely arranged first side surfaces and two oppositely arranged second side surfaces, the first side surfaces and the second side surfaces form an opening, one of the first side surfaces forms the bottom wall, and the other of the first side surfaces forms the top wall; a cover body closing the opening.

31. The battery cell of claim 30, wherein, The area of the first side surface is smaller than the area of the second side surface.

32. A battery device, characterized by The battery device comprises a plurality of battery cells according to any one of claims 1 to 31.

33. An electrical device, comprising: The battery device comprises at least one of the battery cell according to any one of claims 1 to 31 and the battery device according to claim 32.

34. An energy storage device, comprising: The battery device comprises at least one of the battery cell according to any one of claims 1 to 31 and the battery device according to claim 32.

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