Insulator, cylindrical battery cell, battery device, and electric device

Abstract

The application relates to a separator, a cylindrical battery monomer, a battery device and an electric equipment. The separator comprises a porous base film and a coating layer. The coating layer comprises a base part, a plurality of first support parts and a plurality of second support parts. The base part is arranged on the surface of the porous base film. At least part of the first support parts protrudes from the base part. At least part of the second support parts protrudes from the base part. The average value of the protruding height of the plurality of first support parts is greater than the average value of the protruding height of the second support parts. The compression modulus of the first support parts is smaller than the compression modulus of the second support parts. The first support parts comprise at least one organic particle. The second support parts comprise at least one first inorganic particle. The separator provided by the application is characterized in that the protruding heights of the first support parts and the second support parts are different, which is beneficial to the hierarchical buffering of compressive stress. The second support parts can relieve the excessive compression of the first support parts, and the compression bearing capacity of the coating layer is improved.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to separators, cylindrical battery cells, battery devices and electrical equipment. Background Technology

[0002] Batteries are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] As the requirements for energy density gradually increase, the diameter of cylindrical battery cells is gradually increasing. However, with the gradual increase in the diameter of cylindrical battery cells, the number of turns of the electrode plates in the electrode assembly increases, leading to a decrease in the stability of the cylindrical battery cells and affecting their cycle life. Summary of the Invention

[0004] This application provides an separator, a cylindrical battery cell, a battery device, and an electrical device, which aim to improve the cycle life of the cylindrical battery cell to a certain extent.

[0005] In a first aspect, this application discloses a separator comprising a porous base membrane and a coating. The coating includes a substrate portion, a plurality of first support portions, and a plurality of second support portions. The substrate portion is disposed on the surface of the porous base membrane. At least a portion of each of the first support portions protrudes from the substrate portion, and at least a portion of each of the second support portions protrudes from the substrate portion. The average protrusion height of the plurality of first support portions is greater than the average protrusion height of the second support portions. The compressive modulus of the first support portions is less than the compressive modulus of the second support portions. Each first support portion includes at least one organic particle. Each second support portion includes at least one first inorganic particle.

[0006] The separator provided in this application comprises a coating including a substrate, a first support portion, and a second support portion. Both the first and second support portions protrude from the substrate, with the first support portion protruding at a greater height than the second support portion. When applied to a cylindrical battery cell, the different protrusion heights of the first and second support portions during battery cell discharge facilitate graded buffering of compressive stress on the negative electrode, thus mitigating electrode expansion. The compressive modulus of the first support portion is lower than that of the second support portion, allowing the second support portion to alleviate excessive compression of the first support portion, thereby enhancing the coating's compressive strength and improving the gap consistency between the positive and negative electrodes in the wound electrode assembly. Furthermore, the first support portion provides a suitable gap between the positive and negative electrodes, offering the space required for electrode expansion, improving the mechanical stability of the central hole structure of the electrode assembly, reducing the probability of electrode assembly collapse, and thus improving the reliability and cycle life of the battery cell.

[0007] According to one embodiment of this application, the compressive modulus of the second support portion is greater than or equal to 10 GPa. The high compressive modulus of the second support portion can alleviate the expansion of the negative electrode sheet and suppress excessive compressive deformation of the first support portion, resulting in a suitable gap between the positive and negative electrode sheets and a more uniform gap distribution throughout the electrode assembly.

[0008] According to one embodiment of this application, the first support portion includes at least one organic particle. The volume average particle size Dv50 of the first inorganic particle is smaller than that of the organic particle. The large-diameter organic particle and the small-diameter first inorganic particle can balance the elastic deformation and rigid support of the coating structure, which is beneficial to improving the consistency of the gap between the positive and negative electrode plates and protecting the stability of the central hole of the electrode assembly.

[0009] According to one embodiment of this application, the volume average particle size Dv50 of the first inorganic particles is 3 μm to 30 μm. Small-diameter first inorganic particles are easily and uniformly dispersed in the layer, reducing agglomeration and providing rigid support for the coating. The suitable particle size of the first inorganic particles mitigates the impact of excessively large particle size on the expansion of the negative electrode sheet.

[0010] According to one embodiment of this application, the volume average particle size Dv50 of the organic particles is between 5 μm and 100 μm. The organic particles with different particle sizes are graded with the first inorganic particles, so that the support portion of the separator has a gradient structure in the thickness direction, which is beneficial for the graded buffering of expansion forces.

[0011] According to one embodiment of this application, the organic particles include at least one of olefin and olefin derivative polymers and vinyl polymers.

[0012] According to one embodiment of this application, olefin and olefin derivative polymers include one or more of polyvinylidene fluoride, polyhexafluoropropylene, polyethylene, polypropylene, polyvinyl chloride, polyvinyl chloride, polystyrene, and polybutadiene.

[0013] According to one embodiment of this application, the vinyl polymer includes one or more of polyacrylic acid, polymethyl acrylate, and polyacrylonitrile.

[0014] According to one embodiment of this application, the substrate includes second inorganic particles, the volume average particle size Dv50 of which is smaller than that of the first inorganic particles. The substrate formed by the inorganic particles has high mechanical strength, improving the puncture resistance of the coating and effectively blocking lithium dendrite penetration. It also gives the separator high electrolyte wettability and high temperature resistance. Simultaneously, when the porous base film layer is subjected to compressive deformation, the substrate formed by the inorganic particles can effectively support both the organic particles and the first inorganic particles.

[0015] According to one embodiment of this application, the volume average particle size Dv50 of the second inorganic particles is 0.5 μm to 3 μm. The smaller particle size of the second inorganic particles allows them to adhere tightly to the surface of the porous substrate film.

[0016] According to one embodiment of this application, the first inorganic particle and the second inorganic particle each independently include one or more of boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silicon dioxide, tin dioxide, titanium dioxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, cerium oxide, zirconium titanate, barium titanate, and magnesium fluoride.

[0017] According to one embodiment of this application, at least a portion of the first support portion is embedded in the base portion. Embedding at least a portion of the first support portion into the base portion can increase the connection area between the first support portion and the base portion, thereby improving the connection strength.

[0018] According to one embodiment of this application, at least a portion of the second support portion is embedded in the base portion. Embedding at least a portion of the second support portion into the base portion can increase the connection area between the second support portion and the base portion, thereby improving the connection strength.

[0019] Secondly, this application proposes a cylindrical battery cell, which includes a housing and an electrode assembly, with the electrode assembly housed within the housing. The electrode assembly includes a positive electrode, a negative electrode, and a separator as described above. The separator is used to isolate the positive electrode and the negative electrode. The positive electrode, the negative electrode, and the separator are wound along a winding direction. In the wound state, the first support portion is compressed, and the second support portion does not protrude from the first support portion.

[0020] The cylindrical battery cell provided in this application, when the cylindrical battery cell is discharged, the separator is beneficial for the graded buffering of the compressive stress of the negative electrode, which helps to alleviate the expansion of the electrode, and also helps to improve the gap consistency between the positive and negative electrodes of the wound electrode assembly, thereby improving the reliability and cycle life of the cylindrical battery cell.

[0021] According to one embodiment of this application, a gap is formed between the positive electrode and the negative electrode, extending along the winding direction. The gap has a winding start gap and a winding end gap along the winding direction. The minimum value L1 of the winding start gap and the maximum value L2 of the winding end gap satisfy: L2-L1≤10μm. This ensures a more uniform gap between the two electrode sections, mitigating the increased ion transport resistance caused by an excessively small gap at the start and the increased side reactions caused by an excessively large gap at the end. This is beneficial for improving ion transport and active material utilization, and enhancing battery performance consistency.

[0022] Thirdly, this application proposes a method for manufacturing a cylindrical battery cell, comprising:

[0023] A separator is provided, comprising a porous base membrane and a coating. The coating includes a substrate, a plurality of first supports, and a plurality of second supports. The substrate is disposed on the surface of the porous base membrane. At least a portion of each of the first supports protrudes from the substrate, and at least a portion of each of the second supports protrudes from the substrate. The average protrusion height of the plurality of first supports is greater than the average protrusion height of the second supports. Each first support includes at least one organic particle. Each second support includes at least one first inorganic particle.

[0024] A positive electrode, a negative electrode, and a separator are wound along the winding direction to form an electrode assembly. The separator is used to isolate the positive electrode and the negative electrode. In the winding state, the first support portion of the separator is compressed, and the second support portion does not protrude from the first support portion.

[0025] Place the electrode assembly inside the housing.

[0026] The manufacturing method of the cylindrical battery cell of this application has different states of the separator before and after winding. That is, the first support part of the separator is compressed and deformed, and the second support part can prevent the first support part from being over-compressed and deformed. This achieves the consistency of the gap between the positive and negative electrode plates of the wound electrode assembly, and also improves the reliability and cycle life of the cylindrical battery cell.

[0027] Fourthly, this application provides a battery device, which includes the aforementioned cylindrical battery cell.

[0028] Fifthly, this application provides an electrical device, which includes the aforementioned plurality of cylindrical battery cells and the aforementioned battery assembly.

[0029] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0030] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0031] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0032] Figure 2 Schematic diagram of a battery device provided for some embodiments of this application;

[0033] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0034] Figure 4 This is a schematic diagram of the structure of a cylindrical battery cell provided in some embodiments of this application;

[0035] Figure 5 for Figure 4 An exploded view of a cylindrical battery cell;

[0036] Figure 6 for Figure 4 A cross-sectional schematic diagram of a cylindrical battery cell shown;

[0037] Figure 7 A partial schematic diagram of the isolation member in a flattened state provided in some embodiments of this application;

[0038] Figure 8 A partial schematic diagram of the spacer in a flattened state, provided for other embodiments of this application;

[0039] Figure 9 Partial cross-sectional schematic diagram of the isolation member provided in some embodiments of this application;

[0040] Figure 10 Another partial cross-sectional schematic diagram of the isolation member provided in some embodiments of this application;

[0041] Figure 11 A flowchart illustrating a method for manufacturing a cylindrical battery cell according to some embodiments of this application.

[0042] The accompanying drawings may not be drawn to scale.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Housing; 5a. First housing; 5b. Second housing; 6. Battery module; 7. Cylindrical battery cell; 10. Electrode assembly; 11. Positive electrode; 12. Negative electrode; 13. Separator; 131. Porous base film; 132. Coating; 1321. Substrate; 1322. First support; 1323. Second support; 14. Gap; 14a. Winding start gap; 14b. Winding end gap; 20. Outer shell; 21. Housing; 22. End cap; V. Winding direction. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0047] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0048] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0049] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0050] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0051] In this application, "multiple" means two or more (including two).

[0052] Currently, judging from market trends, the application of batteries is becoming increasingly widespread. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace, among other fields.

[0053] A battery device typically refers to a single physical module comprising multiple battery cells to provide higher voltage and capacity. A battery cell can be the smallest unit that makes up a battery device.

[0054] As the requirements for energy density gradually increase, cylindrical battery cells are developing towards larger diameters. The increase in the size of cylindrical battery cells leads to an increase in energy density. During the winding and forming process of cylindrical electrode assemblies, influenced by factors such as electrode tension and material deformation, the pressure between adjacent turns of the electrode exhibits a gradient decrease as the winding radius increases, forming a "tight inside, loose outside" structural characteristic. This causes some areas of the separator between the electrodes to be over-compressed, thus affecting the reliability and cycle life of the cylindrical battery cell. The above statements are only used to provide background information related to this application and do not necessarily constitute prior art.

[0055] The separator provided in this application comprises a coating including a substrate, a first support portion, and a second support portion. Both the first and second support portions protrude from the substrate, with the first support portion protruding at a greater height than the second support portion. When applied to a cylindrical battery cell, the different protrusion heights of the first and second support portions during battery cell discharge facilitate graded buffering of compressive stress on the negative electrode, thus mitigating electrode expansion. The compressive modulus of the first support portion is lower than that of the second support portion, allowing the second support portion to alleviate excessive compression of the first support portion, thereby enhancing the coating's compressive strength and improving the gap consistency between the positive and negative electrodes in the wound electrode assembly. Furthermore, the first support portion provides a suitable gap between the positive and negative electrodes, offering the space required for electrode expansion, improving the mechanical stability of the central hole structure of the electrode assembly, reducing the probability of electrode assembly collapse, and thus improving the reliability and cycle life of the cylindrical battery cell.

[0056] The cylindrical battery cell described in this application is applicable to batteries and electrical devices that use batteries. This cylindrical battery cell can be used, but is not limited to, batteries, and can also be used in products such as vehicles, aircraft, ships, electronic devices, and power tools, thereby improving the reliability of these products.

[0057] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.

[0058] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device according to an embodiment of this application.

[0059] See Figure 1 As shown, one embodiment of this application provides a vehicle 1. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. In one embodiment of this application, vehicle 1 may include a motor 4, a controller 3, and a battery device 2. The controller 3 is used to control the battery device 2 to supply power to the motor 4. The motor 4 is connected to the wheels via a transmission mechanism, thereby driving vehicle 1. The battery device 2 can serve as the driving power source for vehicle 1, replacing or partially replacing gasoline or natural gas to provide driving power to vehicle 1. In one example, the battery device 2 can be installed at the bottom, front, or rear of vehicle 1. The battery device 2 can be used to supply power to vehicle 1. In one example, the battery device 2 can serve as the operating power source for the vehicle 1's electrical system. Exemplarily, the battery device 2 can be used to meet the power needs of vehicle 1 during startup, navigation, and operation.

[0060] In some embodiments, the battery device 2 may include one or more battery cell assemblies for providing voltage and capacity.

[0061] A battery cell assembly may include multiple cylindrical battery cells, which are connected in series, parallel, or mixed connection via a busbar. Mixed connection refers to multiple cylindrical battery cells being connected in both series and parallel connections.

[0062] Cylindrical battery cells can be rechargeable battery cells. Rechargeable battery cells refer to battery cells that can be recharged after being discharged to activate the active materials and continue to be used.

[0063] As an example, cylindrical battery cells can be lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-metal hydride battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc.

[0064] In some embodiments, a battery cell assembly is typically formed by arranging multiple cylindrical battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple cylindrical battery cells to form an independent module.

[0065] As an example, a battery module can be formed by bundling multiple cylindrical battery cells together with cable ties.

[0066] Figure 2 A schematic diagram of a battery device provided for some embodiments of this application.

[0067] like Figure 2 As shown, in some embodiments, the battery device 2 can be a battery pack, which includes a housing 5 and one or more battery cell assemblies housed within the housing 5. As an example, the battery cell assembly can be a battery module 6, which can be housed within the housing by fixing the battery module 6 to the housing. As an example, the battery cell assembly can also be housed within the housing by directly fixing multiple cylindrical battery cells to the housing.

[0068] In some embodiments, the housing 5 is used to house cylindrical battery cells, and the housing 5 can have various structures.

[0069] In some embodiments, the housing 5 may include a first housing 5a and a second housing 5b. The first housing 5a and the second housing 5b are fastened together to form a closed space inside the housing 5 to house the battery cell assembly. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first housing may be a top cover or a bottom plate.

[0070] In some embodiments, the housing 5 may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are respectively connected to the frame, forming an enclosed space inside the housing to accommodate individual battery cells. As an example, the frame may include multiple side beams.

[0071] In some embodiments, the housing 5 may be part of the vehicle's chassis structure. For example, a portion of the housing 5 may be at least a portion of the vehicle's floor, or a portion of the housing 5 may be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0072] In some embodiments, the battery device 2 may be an energy storage device.

[0073] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, energy storage devices can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours.

[0074] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0075] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0076] In some embodiments, such as Figure 3 As shown, there are multiple cylindrical battery cells 7. These multiple cylindrical battery cells 7 are first connected in series, parallel, or in a mixed manner to form a battery module 6. The multiple battery modules 6 are then connected in series, parallel, or in a mixed manner to form a whole, which is housed in the casing.

[0077] Multiple cylindrical battery cells 7 in battery module 6 can be electrically connected through busbars to achieve parallel, series, or mixed connection of multiple cylindrical battery cells 7 in battery module 6. There can be one or more busbars, each used to electrically connect at least two cylindrical battery cells 7.

[0078] See Figures 4 to 8 , Figure 4 This is a schematic diagram of the structure of a cylindrical battery cell provided in some embodiments of this application; Figure 5 for Figure 4 An exploded view of a cylindrical battery cell; Figure 6 for Figure 4 A cross-sectional schematic diagram of a cylindrical battery cell shown; Figure 7 This is a partial schematic diagram of the separator of a cylindrical battery cell provided in some embodiments of this application in a flattened state; Figure 8 This is a partial schematic diagram of the separator of a cylindrical battery cell provided in other embodiments of this application in a flattened state.

[0079] like Figures 4 to 8 As shown, this application proposes an isolation member 13, which includes a porous base membrane 131 and a coating 132. The coating 132 includes a substrate portion 1321, a plurality of first support portions 1322 and a plurality of second support portions 1323. The substrate portion 1321 is disposed on the surface of the porous base membrane 131. At least a portion of the first support portions 1322 protrudes from the substrate portion 1321, and at least a portion of the second support portions 1323 protrudes from the substrate portion 1321.

[0080] The micropores in the porous base membrane 131 allow ions to pass through.

[0081] As an example, the main material of the porous base membrane 131 can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film.

[0082] In some examples, the porous base membrane 131 has a coating 132 on only one side, and at least a portion of the first support portion 1322 protrudes from the base portion 1321, and at least a portion of the second support portion 1323 protrudes from the base portion 1321.

[0083] In some examples, the porous base membrane 131 has a coating 132 on both sides, and at least a portion of the first support portion 1322 of the coating 132 on both sides protrudes from the base portion 1321, and at least a portion of the second support portion 1323 protrudes from the base portion 1321.

[0084] The protrusion height of the first support portion 1322 refers to the height by which the first support portion 1322 protrudes from the surface of the substrate portion 1321 in the thickness direction of the separator 13. Specifically, in the thickness direction of the separator 13, the distance between the point of the first support portion 1322 furthest from the porous base film 131 and the surface of the substrate portion 1321 can be the protrusion height of the first support portion, and the distance between the point of the second support portion 1323 furthest from the porous base film 131 and the surface of the substrate portion 1321 can be the protrusion height of the second support portion 1323.

[0085] In some examples, the first support portion 1322 may protrude entirely from the surface of the base portion 1321; alternatively, a portion of the first support portion 1322 may be embedded in the base portion 1321, while another portion protrudes from the surface of the base portion 1321.

[0086] In some examples, the second support portion 1323 may protrude entirely from the surface of the base portion 1321; alternatively, a portion of the second support portion 1323 may be embedded in the base portion 1321, while another portion protrudes from the surface of the base portion 1321.

[0087] In some examples, multiple first support portions 1322 are distributed on the surface of the base portion 1321.

[0088] In some examples, multiple second support portions 1323 are distributed on the surface of the base portion 1321.

[0089] In some examples, a plurality of first support portions 1322 and a plurality of second support portions 1323 are distributed on the surface of the base portion 1321.

[0090] The average protrusion height of the plurality of first support portions 1322 of coating 132 and the average protrusion height of the plurality of second support portions 1323 of coating 132 can be tested using equipment and methods known in the art. For example, it can be tested by ion-polished cross-sectional morphology (CP) images. As an example, the procedure can be as follows: cut the spacer 13 into a sample of a certain size (e.g., 6 mm × 6 mm), freeze the sample, and then use a scanning electron microscope (e.g., ZEISS Sigma300) to finally obtain an ion-polished cross-sectional morphology (CP) image of the sample. Both sides of the spacer 13 may be provided with coatings 132. For ease of description, the coatings 132 on both sides of the spacer 13 are defined as the upper coating and the lower coating, respectively. The number of first supports and the protrusion height of each first support, the number of second supports and the protrusion height of each second support in the upper coating, and the number of first supports and the protrusion height of each second support in the lower coating are statistically analyzed in the ion-polished cross-sectional morphology (CP) images. The above tests are repeated with multiple test samples (e.g., 10 samples). The arithmetic mean of the protrusion heights of the first supports of all upper coatings in the multiple test samples (i.e., the ratio of the sum of the protrusion heights of the first supports of the upper coatings in the multiple test samples to the total number of first supports) and the arithmetic mean of the protrusion heights of the second supports are calculated. This average can be used as the average protrusion height of the multiple first supports and the average protrusion height of the multiple second supports of the coating located on the upper side of the porous base film. Calculate the arithmetic mean of the protrusion heights of the first support portions of all the lower coatings in multiple test samples (i.e., the ratio of the sum of the protrusion heights of the first support portions of the lower coatings of multiple test samples to the total number of first support portions), and the arithmetic mean of the protrusion heights of the second support portions. This average value can be used as the average of the protrusion heights of the multiple first support portions and the average of the protrusion heights of the multiple second support portions of the coating located on the lower side of the porous base film.

[0091] The average protrusion height of the plurality of first support portions 1322 is greater than the average protrusion height of the plurality of second support portions 1323.

[0092] The average protrusion height of the multiple first support portions 1322 is relatively large, and the first support portions 1322 can support the positive electrode film layer and the negative electrode film layer. This creates a large gap between the positive electrode sheet 11 and the negative electrode sheet 12, providing space for the expansion of the negative electrode film layer of the negative electrode sheet 12. After the negative electrode film layer expands, it is compressed and undergoes compressive deformation.

[0093] Optionally, the plurality of first support portions 1322 are configured to be compressible.

[0094] The average protrusion height of the multiple second support portions 1323 is relatively small, and they come into contact with the second support portions 1323 after the negative electrode film expands to a certain extent.

[0095] The compressive modulus of the first support portion 1322 is less than that of the second support portion 1323. That is, the first support portion 1322 has a smaller compressive modulus, while the second support portion 1323 has a larger compressive modulus. The first support portion 1322 can be compressed and deformed more, providing space for the expansion of the negative electrode film. The second support portion 1323 can be compressed and deformed less. The second support portion 1323 can alleviate the expansion of the negative electrode film and inhibit further compression deformation of the first support portion 1322.

[0096] The term "compression modulus" measures the degree of deformation of a material when subjected to compressive force. A higher compression modulus means that the material undergoes less volume change under pressure, exhibiting better stability and resistance to deformation; conversely, a lower compression modulus means that the material undergoes greater volume change under pressure.

[0097] Compression modulus can be tested using equipment and methods known in the art, such as in accordance with the national standard GB / T1041-2008 Test for Compression Properties of Plastics. For example, the first support 1322 can be fabricated as a fixed area, with 500 layers per group (approximately 5 mm thick) for compression testing.

[0098] In some embodiments, the compressive modulus of all first support portions 1322 is less than the compressive modulus of the second support portion 1323. That is, the compressive modulus of the first support portion 1322 is smaller, and the compressive modulus of the second support portion 1323 is larger. The first support portion 1322 has greater compressibility deformation, providing space for the expansion of the negative electrode film layer. The second support portion 1323 has less compressibility deformation.

[0099] The protrusion height of the first support portion 1322 is greater than the protrusion height of all the second support portions 1323.

[0100] The second support portion 1323 includes at least one first inorganic particle.

[0101] In some examples, the second support portion 1323 includes a plurality of first inorganic particles dispersed in the matrix portion 1321.

[0102] As an example, in the ion-polished cross-sectional morphology (CP) image of the separator 13, the first inorganic particles of the second support 1323 are non-agglomerated particles and have a solid spherical cross-section.

[0103] For example, multiple first inorganic particles are distributed in an island-like pattern on the substrate 1321. The island-like alternating distribution structure allows the positive electrode 11 and the negative electrode 12 to have a suitable gap while also reducing the overall weight of the coating 132.

[0104] The first inorganic particles have a high compressive modulus, which increases the overall compressive strength of the coating 132 and can improve the problem of the small gap near the center hole of the electrode assembly 10.

[0105] like Figure 7 and Figure 8 As shown, the first support portion 1322 includes at least one organic particle.

[0106] When subjected to the expansion of the electrode, the first support portion 1322 formed by the organic particles undergoes elastoplastic deformation.

[0107] In some examples, the first support portion 1322 includes a plurality of organic particles dispersed in the matrix portion 1321.

[0108] In some examples, multiple organic particles and multiple first inorganic particles are dispersed on the surface of the substrate 1321. This gives the separator 13 high permeability, resulting in better cycle performance and reliability for the cylindrical battery cell 7.

[0109] In other examples, organic particles form a second region on the surface of the substrate 1321, and first inorganic particles form a first region on the surface of the substrate 1321. The first and second regions are arranged along the winding axis direction of the electrode assembly 10.

[0110] Optionally, the second region includes multiple second sub-regions, the first region includes multiple first sub-regions, and the multiple second sub-regions and multiple first sub-regions are arranged alternately along the winding axis.

[0111] Optionally, the second region includes multiple second sub-regions, the first region includes multiple first sub-regions, and the multiple second sub-regions and multiple first sub-regions are arranged alternately along the winding direction V of the electrode assembly 10.

[0112] As an example, in the ion-polished cross-sectional morphology (CP) image of the separator 13, the first inorganic particles of the second support portion 1323 are non-agglomerated particles with a solid spherical cross-section. The organic particles of the first support portion 1322 are non-agglomerated particles with a solid spherical cross-section. The first inorganic particles and organic particles are arranged alternately.

[0113] Organic particles can act as a support to form gaps between the positive electrode 11 and the negative electrode 12. In the event of thermal runaway in the cylindrical battery cell 7, the organic particles can melt at high temperatures and form a dense polymer film, thereby reducing the diffusion channels of active ions, slowing down ion transport, and delaying the time of thermal propagation, thus improving the reliability of the cylindrical battery cell 7.

[0114] The separator 13 provided in this application includes a coating 132 comprising a substrate 1321, a first support 1322, and a second support 1323. Both the first support 1322 and the second support 1323 protrude from the substrate 1321, with the first support 1322 having a greater protrusion height than the second support 1323. When the separator 13 is applied to a cylindrical battery cell 7, the different protrusion heights of the first support 1322 and the second support 1323 during discharge facilitate the graded buffering of compressive stress on the negative electrode 12, thereby alleviating electrode expansion. The compressive modulus of the first support 1322 is less than that of the second support 1323, and the second support 1323 can alleviate excessive compression of the first support 1322, improving the compressive load-bearing capacity of the coating 132 and enhancing the consistency of the gap between the positive electrode 11 and the negative electrode 12 of the wound electrode assembly 10. Moreover, the first support portion 1322 and the second support portion 1323 cooperate to provide a suitable gap between the positive electrode 11 and the negative electrode 12, providing the space required for the expansion of the electrode, improving the mechanical stability of the central hole structure of the electrode assembly 10, reducing the probability of the electrode assembly 10 collapsing, thereby improving the reliability and cycle life of the cylindrical battery cell.

[0115] According to one embodiment of this application, the compression modulus of the second support portion 1323 is greater than or equal to 10 GPa.

[0116] As an example, the compression modulus of the second support 1323 is 10 GPa, 50 GPa, 100 GPa, 150 GPa, 200 GPa, 250 GPa, 300 GPa, 350 GPa, 400 GPa, 450 GPa, 500 GPa, or any value between any two of the above values.

[0117] Optionally, the compression modulus of the second support 1323 is greater than or equal to 100 GPa.

[0118] Alternatively, the compression modulus of the second support 1323 is greater than or equal to 100 GPa and less than or equal to 300 GPa.

[0119] In some examples, the compressive modulus of the first support 1322 is less than 10 GPa.

[0120] Optionally, the compression modulus of the first support portion 1322 is less than 0.1 GPa to 3 GPa.

[0121] The second support portion 1323 has a high compression modulus, which can alleviate the expansion of the negative electrode 12 and suppress the excessive compression deformation of the first support portion 1322, so that there is a suitable gap between the positive electrode 11 and the negative electrode 12, and also make the overall gap distribution of the electrode assembly 10 more uniform.

[0122] like Figure 7 As shown, one side of the isolation member 13 has a coating 132. Before and after the isolation member 13 is compressed, the height difference of the first support portion 1322 on the coating 132 is H1.

[0123] like Figure 8 As shown, both sides of the isolation member 13 have a coating 132. Before and after the isolation member 13 is compressed, the total height difference of the first support portion 1322 on the coating 132 is 2H2.

[0124] According to one embodiment of this application, the volume average particle size Dv50 of the first inorganic particle is smaller than the volume average particle size Dv50 of the organic particle.

[0125] The volume average particle size Dv50 is a well-known concept in the art. Dv50 refers to the particle size corresponding to 50% of the volume distribution and can be determined using instruments and methods known in the art. For example, the volume average particle size Dv50 of the first inorganic particles and the volume average particle size Dv50 of the organic particles are tested using a laser particle size analyzer, in accordance with GB / T 19077-2016. For example, the laser particle size analyzer can be a MasterSizer 3000 laser particle size analyzer.

[0126] The large-diameter organic particles and the small-diameter first inorganic particles can balance the elastic deformation and rigid support of the coating 132 structure, which is beneficial to improving the consistency of the gap between the positive electrode 11 and the negative electrode 12 and protecting the stability of the central hole of the electrode assembly 10.

[0127] According to one embodiment of this application, the volume average particle size Dv50 of the first inorganic particle is 3 μm to 30 μm.

[0128] As an example, the volume average particle size Dv50 of the first inorganic particle is 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, or a value between any two of the above.

[0129] Optionally, the volume average particle size Dv50 of the first inorganic particle is 3 μm to 10 μm.

[0130] Small-diameter first inorganic particles are easy to disperse uniformly in the layer, reducing the occurrence of agglomeration and providing rigid support for coating 132. The first inorganic particles have a suitable particle size, which improves the expansion of the negative electrode sheet 12 caused by the excessive particle size of the first inorganic particles.

[0131] According to one embodiment of this application, the volume average particle size Dv50 of the organic particles is from 5 μm to 100 μm.

[0132] As an example, the volume average particle size Dv50 of the organic particles is 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, or any value between two of the above.

[0133] Optionally, the volume average particle size Dv50 of the organic particles is from 5 μm to 30 μm. Appropriately reducing the particle size of the organic particles reduces the space occupied by the coating 132 in the radial direction of the cylindrical battery cell 7.

[0134] Organic particles of different sizes are graded with the first inorganic particles, so that the support part of the separator 13 has a gradient structure in the thickness direction, which is beneficial to the graded buffering of the expansion force.

[0135] According to one embodiment of this application, the organic particles include at least one of olefin and olefin derivative polymers and vinyl polymers.

[0136] Optionally, olefins and olefin derivative polymers include one or more of polyvinylidene fluoride, polyhexafluoropropylene, polyethylene, polypropylene, polyvinyl chloride, polyvinyl chloride, polystyrene, and polybutadiene.

[0137] Optionally, vinyl polymers include one or more of polyacrylic acid, polymethyl acrylate, and polyacrylonitrile.

[0138] According to one embodiment of this application, the matrix portion 1321 includes second inorganic particles, the volume average particle size Dv50 of the second inorganic particles being smaller than the volume average particle size Dv50 of the first inorganic particles.

[0139] Optionally, the substrate 1321 is stacked with the porous base membrane 131. The second inorganic particles with smaller particle size can be continuously distributed in a planar manner on the porous base membrane 131.

[0140] In some examples, a second inorganic particle may be coated on a porous base membrane 131 to form a substrate 1321, and then a plurality of organic particles and a first inorganic particle may be coated on the surface of the substrate 1321; in this example, the organic particles and the first inorganic particles may protrude integrally from the surface of the substrate 1321.

[0141] In other examples, the first inorganic particles, the second inorganic particles, and the organic particles can be mixed first and then coated together onto the porous base membrane 131. In this example, at least a portion of the plurality of first inorganic particles is embedded in the substrate portion 1321, and at least a portion of the plurality of organic particles is embedded in the substrate portion 1321.

[0142] The matrix 1321 formed by the second inorganic particles has high mechanical strength, which improves the puncture resistance of the coating 132 and effectively blocks lithium dendrite penetration. It also gives the separator 13 high electrolyte wettability and high temperature resistance. At the same time, when the porous base film 131 is subjected to compression deformation, the matrix 1321 formed by the second inorganic particles can effectively support the organic particles and the first inorganic particles.

[0143] According to one embodiment of this application, the volume average particle size Dv50 of the second inorganic particle is 0.5 μm to 3 μm.

[0144] As an example, the volume average particle size Dv50 of the second inorganic particle is 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1.0μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm, 2.0μm, 2.1μm, 2.2μm, 2.3μm, 2.4μm, 2.5μm, 2.6μm, 2.7μm, 2.8μm, 2.9μm, 3.0μm, or any value between any two of the above.

[0145] Optionally, the volume average particle size Dv50 of the second inorganic particle is 0.5 μm to 1 μm.

[0146] The smaller inorganic particles can adhere tightly to the surface of the porous base membrane 131.

[0147] In some embodiments, the organic particles in the coating 132 account for 10% to 20% of the mass, the first inorganic particles in the coating 132 account for 10% to 20% of the mass, and the second inorganic particles in the coating 132 account for 60% to 75% of the mass.

[0148] As an example, the mass percentage of organic particles in coating 132 can be 10% to 15%.

[0149] As an example, the mass percentage of the first inorganic particles in coating 132 is 15% to 20%.

[0150] As an example, the mass percentage of the second inorganic particles in coating 132 is 60% to 70%.

[0151] By making the organic particles in coating 132 account for 10% to 20% of the mass and the first inorganic particles account for 10% to 20% of the mass, the supporting capacity of the organic particles and the organic particles can be balanced, thereby improving the gap consistency between the positive electrode 11 and the negative electrode 12 and improving the cycle life of the cylindrical battery cell 7.

[0152] According to one embodiment of this application, the first inorganic particle and the second inorganic particle each independently include one or more of boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silicon dioxide, tin dioxide, titanium dioxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, cerium oxide, zirconium titanate, barium titanate, and magnesium fluoride.

[0153] According to one embodiment of this application, at least a portion of the first support portion 1322 is embedded in the base portion 1321.

[0154] In some examples, all the first support portions 1322 are embedded in the base portion 1321.

[0155] In other examples, a portion of the first support portion 1322 is embedded in the base portion 1321, while another portion of the first support portion 1322 protrudes entirely from the surface of the base portion 1321.

[0156] Embedding at least a portion of the first support portion 1322 into the base portion 1321 can increase the connection area between the first support portion 1322 and the base portion 1321, thereby increasing the connection strength.

[0157] According to one embodiment of this application, at least a portion of the second support portion 1323 is embedded in the base portion 1321.

[0158] In some examples, all the second support portions 1323 are embedded in the base portion 1321.

[0159] In other examples, a portion of the second support portion 1323 is embedded in the base portion 1321, while another portion of the second support portion 1323 protrudes entirely from the surface of the base portion 1321.

[0160] Embedding at least a portion of the second support portion 1323 into the base portion 1321 can increase the connection area between the second support portion 1323 and the base portion 1321, thereby increasing the connection strength.

[0161] Secondly, such as Figure 4 and 5As shown, this application proposes a cylindrical battery cell 7, which includes a housing 20 and an electrode assembly 10, the electrode assembly 10 being housed within the housing 20. The housing 20 is a hollow structure, with an internal space for accommodating the electrode assembly 10, and optionally, an electrolyte. The housing 20 of the cylindrical battery cell 7 is cylindrical.

[0162] As an example, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening and the end cap 22 for closing the opening.

[0163] The housing 21 is a component used to fit the end cap 22 to form the internal cavity of the cylindrical battery cell 7. The formed internal cavity can be used to accommodate the electrode assembly 10 and other components.

[0164] The housing 21 and the end cap 22 can be separate components. For example, an opening can be provided on the housing 21, and the end cap 22 can be used to close the opening to form an internal cavity for the cylindrical battery cell 7.

[0165] The shape of the end cap 22 can be adapted to the shape of the housing 21 to fit the housing 21. The material of the end cap 22 can be the same as or different from the material of the housing 21.

[0166] The end cap 22 is connected to the housing 21 by welding, bonding, snap-fitting or other means.

[0167] The housing 21 may be open at one end or open at both ends. In some examples, the housing 21 may be a structure with an opening on one side, and one end cap 22 is provided to cover the housing 21. In other examples, the housing 21 may also be a structure with openings on both sides, and two end caps 22 are provided, with the two end caps 22 respectively covering the two openings of the housing 21.

[0168] like Figure 6 As shown, the electrode assembly 10 includes a positive electrode 11, an insulating member 13, and a negative electrode 12. The insulating member 13 is used to isolate the positive electrode 11 and the negative electrode 12. The positive electrode 11, the negative electrode 12, and the insulating member 13 are wound along the winding direction V.

[0169] Electrode assembly 10 is the component in the cylindrical battery cell 7 where the electrochemical reaction occurs.

[0170] In some embodiments, the electrode assembly 10 includes a positive electrode 11 and a negative electrode 12. During the charging and discharging process of the cylindrical battery cell 7, active ions (e.g., lithium ions) are inserted and extracted back and forth between the positive electrode 11 and the negative electrode 12.

[0171] In some embodiments, the positive electrode 11 includes a positive current collector and a positive electrode film layer, with the positive electrode film layer disposed on at least one side of the positive current collector. As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0172] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0173] In some embodiments, the positive electrode film layer includes a positive electrode active material, which includes a nickel-lithium transition metal oxide.

[0174] As an example, examples of nickel-lithium transition metal oxides may include, but are not limited to, lithium nickel-cobalt-manganese oxides and lithium nickel-cobalt-aluminum oxides (such as LiNi). 0.80 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0175] As an example, lithium nickel cobalt manganese oxide can be LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 LiNi 0.9 Co 0.05 Mn 0.05 O2, LiNi 0.92 Co 0.03Mn 0.05 O2, LiNi 0.95 Co 0.02 Mn 0.03 O2 or LiNi 0.96 Co 0.02 Mn 0.02 O2.

[0176] In some embodiments, the negative electrode 12 includes a negative electrode current collector and a negative electrode film layer, with the negative electrode film layer disposed on at least one side of the negative electrode current collector. As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0177] In some embodiments, the negative electrode film layer includes a negative electrode active material. The negative electrode active material may include silicon-based materials and carbon-based materials.

[0178] As an example, silicon-based materials include one or more of silicon-carbon materials, elemental silicon, silicon oxides, silicon-nitrogen compounds, and silicon alloys.

[0179] As an example, carbon-based materials include one or more of artificial graphite, natural graphite, hard carbon, and soft carbon.

[0180] As an example, the negative electrode active material may also include a tin-based material, which may be selected from at least one of elemental tin, tin oxides, and tin alloys.

[0181] Carbon-based materials exhibit stable cycle performance and minimal expansion during charging; silicon-based materials possess high theoretical specific capacity and, as negative electrode active materials, contribute to improving the energy density of the cylindrical battery cell 7. However, silicon-based materials undergo significant volume changes during cycling. This embodiment combines silicon-based and carbon-based materials to reduce the expansion of the negative electrode film, thus balancing the energy density and cycle life of the cylindrical battery cell 7 to a certain extent.

[0182] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0183] In some embodiments, the separator 13 is disposed between the positive electrode 11 and the negative electrode 12. The separator 13 can prevent short circuits between the positive and negative electrodes, while allowing active ions to pass through.

[0184] In some embodiments, the electrode assembly 10 is a wound structure. Exemplarily, the positive electrode 11, the separator 13, and the negative electrode 12 are wound into a cylindrical wound structure along the winding direction V.

[0185] The cylindrical battery cell 7 provided in this application, when the cylindrical battery cell 7 is discharged, the separator 13 is beneficial to the graded buffering of the compressive stress of the negative electrode 12, which is beneficial to the relief of the expansion of the electrode, and also beneficial to improve the gap consistency between the positive electrode 11 and the negative electrode 12 of the wound electrode assembly 10, thereby improving the reliability and cycle life of the cylindrical battery cell 7.

[0186] See also Figure 9 and Figure 10 , Figure 9 A partial cross-sectional schematic diagram of the separator for a cylindrical battery cell provided in some embodiments of this application; Figure 10 This is another partial cross-sectional schematic diagram of the separator of a cylindrical battery cell provided in some embodiments of this application.

[0187] According to one embodiment of this application, such as Figure 6 , Figure 9 and Figure 10 As shown, a gap 14 is formed between the positive electrode 11 and the negative electrode 12. The gap 14 extends along the winding direction V and has a winding start gap 14a and a winding end gap 14b along the winding direction V. The minimum value L1 of the winding start gap 14a and the maximum value L2 of the winding end gap 14b satisfy: L2-L1≤10μm.

[0188] The electrode assembly 10 extends along the winding direction V and forms n winding loops, where n ≥ 20 and n is a natural number; the innermost winding loop is the first winding loop. The outermost winding loop is the nth winding loop.

[0189] The gap 14 has a winding start gap 14a and a winding end gap 14b along the winding direction V, wherein the winding start gap 14a is from the 1st to the 5th turn, and the winding end gap 14b is from the n-5th turn to the nth turn.

[0190] like Figure 9 and Figure 10 As shown, a gap 14 is formed between the positive electrode 11 and the negative electrode 12 along the radial direction of the cylindrical battery cell 7. The gap 14 is the difference between the distance between adjacent positive and negative electrode plates 11 and 12 and the thickness of the porous base film 131 and the substrate 1321 of the separator 13. The minimum value L1 of the winding start gap 14a is the minimum difference between the distance between the positive and negative electrode plates 11 and 12 and the thickness of the porous base film 131 and the substrate 1321 of the separator 13 within the winding start gap 14a. The maximum value L2 of the winding end gap 14b is the maximum difference between the distance between the positive and negative electrode plates 11 and 12 and the thickness of the porous base film 131 and the substrate 1321 of the separator 13 within the winding end gap 14b.

[0191] As an example, the average difference between the distance between the positive electrode 11 and the negative electrode 12 in the first turn of the first to fifth turns in the winding start gap 14a and the thickness of the porous base film 131 and the substrate 1321 of the separator 13 is the minimum value. The average difference between the distance between the positive electrode 11 and the negative electrode 12 in the nth turn of the n-5th to nth turns in the winding finish gap 14b and the thickness of the porous base film 131 and the substrate 1321 of the separator 13 is the maximum value.

[0192] By setting the first support part 1322 and the second support part 1323, the winding start gap 14a and the winding end gap 14b are both controlled within a reasonable range.

[0193] The first support portion 1322 provides a suitable gap 14 between the positive electrode 11 and the negative electrode 12, providing space for the expansion of the electrode, improving the mechanical stability of the central hole structure of the electrode assembly 10, reducing the probability of the electrode assembly 10 collapsing, and thus improving the reliability and cycle life of the cylindrical battery cell 7.

[0194] As an example, the difference between the minimum value L1 of the winding start gap 14a and the maximum value L2 of the winding end gap 14b is 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm or any two of the above values.

[0195] Reference Figure 9 The minimum value L1 of the winding start gap 14a includes a first gap La and a second gap Lb. The first gap La is formed between the positive electrode 11 and the separator 13 in the winding start gap 14a, and the second gap Lb is formed between the negative electrode 12 and the separator 13 in the winding start gap 14a. L1 = La + Lb.

[0196] Reference Figure 10 The minimum value L2 of the winding end gap 14b includes the third gap Lc and the fourth gap Ld. The third gap Lc is formed between the positive electrode 11 and the separator 13 in the winding end gap 14b, and the fourth gap Ld is formed between the negative electrode 12 and the separator 13 in the winding end gap 14b. L2 = Lc + Ld.

[0197] The minimum value L1 of the winding start gap 14a and the maximum value L2 of the winding end gap 14b satisfy: L2-L1≤10μm, which makes the gap between the two electrode sections more uniform, improves the increased ion transport resistance caused by the small gap in the start section, and improves the increased side reactions caused by the large gap in the end section. This is conducive to improving ion transport and active material utilization, and improving battery performance consistency.

[0198] According to one embodiment of this application, under a pressure of 1MPa-7MPa, the minimum value L1 of the winding start gap 14a and the maximum value L2 of the winding end gap 14b satisfy: 3μm≤L2-L1≤10μm.

[0199] Therefore, by cooperating with the substrate 1321, the first support 1322 and the second support 1323 in the coating 132, it is possible to provide expansion space for the electrode sheet and suppress the coating 132 from being over-compressed. This enables the winding end gap 14b and the winding start gap 14a to have a high degree of consistency when the pressure is 1MPa-7MPa.

[0200] See also Figure 11 , Figure 11 A flowchart illustrating a method for manufacturing a cylindrical battery cell according to some embodiments of this application.

[0201] Thirdly, such as Figure 11 As shown, this application proposes a method for manufacturing a cylindrical battery cell, comprising:

[0202] Step S100: Provide a separator, the separator comprising a porous base membrane and a coating, the coating comprising a substrate portion, a plurality of first support portions and a plurality of second support portions, the substrate portion being disposed on the surface of the porous base membrane, at least a portion of the first support portions protruding from the substrate portion, at least a portion of the second support portions protruding from the substrate portion, the average protrusion height of the plurality of first support portions being greater than the average protrusion height of the second support portions, the first support portions comprising at least one organic particle, and the second support portions comprising at least one first inorganic particle.

[0203] Step S200: The positive electrode, negative electrode and separator are wound along the winding direction to form an electrode assembly. The separator is used to isolate the positive electrode and the negative electrode. In the winding state, the first support portion of the separator is compressed and the second support portion does not protrude from the first support portion.

[0204] Step S300: Place the electrode assembly into the housing.

[0205] The manufacturing method of the cylindrical battery cell of this application has different states of the separator before and after winding. That is, after the winding structure is formed, the first support part of the separator is compressed and deformed, and the second support part can prevent the first support part from being over-compressed and deformed. This achieves the consistency of the gap between the positive and negative electrode plates of the wound electrode assembly, and also improves the reliability and cycle life of the battery cell.

[0206] Fourthly, this application provides a battery device, which includes the aforementioned cylindrical battery cell.

[0207] Fifthly, this application provides an electrical device, which includes the aforementioned plurality of cylindrical battery cells and the aforementioned battery assembly.

[0208] This application proposes an isolation element 13, such as Figures 4 to 6 , Figures 8 to 10 As shown, the separator 13 includes a porous base membrane 131 and a coating 132. The coating 132 includes a substrate 1321, a plurality of first support portions 1322, and a plurality of second support portions 1323. The substrate 1321 is disposed on the surface of the porous base membrane 131. At least a portion of the first support portions 1322 protrudes from the substrate 1321, and at least a portion of the second support portions 1323 protrudes from the substrate 1321. The average protrusion height of the plurality of first support portions 1322 is greater than the average protrusion height of the second support portions 1323. The compressive modulus of the first support portions 1322 is less than the compressive modulus of the second support portions 1323.

[0209] The first support portion 1322 is embedded in the substrate portion 1321. The first support portion 1322 includes a plurality of organic particles. The volume average particle size Dv50 of the organic particles is 5 μm to 100 μm. The organic particles include one or more of polyvinylidene fluoride, polyhexafluoropropylene, polyethylene, polypropylene, polyvinyl chloride, polyvinyl chloride, polystyrene, polybutadiene, acrylic acid, polymethyl methacrylate, and polyacrylonitrile.

[0210] The second support portion 1323 is embedded in the matrix portion 1321. The second support portion 1323 includes a plurality of first inorganic particles. The volume average particle size Dv50 of the first inorganic particles is 3 μm to 30 μm. The compressive modulus of the second support portion 1323 is greater than or equal to 100 GPa. The matrix portion 1321 includes second inorganic particles, the volume average particle size Dv50 of which is 0.5 μm to 3 μm. The first and second inorganic particles each independently include one or more of boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silicon dioxide, tin dioxide, titanium dioxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, cerium oxide, zirconium titanate, barium titanate, and magnesium fluoride.

[0211] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A spacer, characterized in that, The separator includes a porous base membrane and a coating. The coating includes a substrate, a plurality of first support portions and a plurality of second support portions. The substrate is disposed on the surface of the porous base membrane. At least a portion of the first support portions protrudes from the substrate, and at least a portion of the second support portions protrudes from the substrate. The average protrusion height of the plurality of first support portions is greater than the average protrusion height of the second support portions; The compression modulus of the first support portion is less than that of the second support portion; The first support portion includes at least one organic particle; The second support portion includes at least one first inorganic particle; The matrix includes second inorganic particles, the volume average particle size Dv50 of the second inorganic particles being smaller than the volume average particle size Dv50 of the first inorganic particles. The organic particles in the coating account for 10% to 20% of the total mass, the first inorganic particles in the coating account for 10% to 20% of the total mass, and the second inorganic particles in the coating account for 60% to 75% of the total mass.

2. The isolation component according to claim 1, characterized in that, The compression modulus of the second support is greater than or equal to 10 GPa.

3. The isolation component according to claim 1, characterized in that, The volume average particle size Dv50 of the first inorganic particle is smaller than the volume average particle size Dv50 of the organic particle.

4. The isolation member according to claim 3, characterized in that, The volume average particle size Dv50 of the first inorganic particle is 3 μm to 30 μm.

5. The isolation member according to claim 1, characterized in that, The volume average particle size Dv50 of the organic particles is 5 μm to 100 μm.

6. The isolation member according to claim 1, characterized in that, The organic particles include at least one of olefin and olefin derivative polymers and vinyl polymers.

7. The isolation member according to claim 6, characterized in that, The olefin and olefin derivative polymers include one or more of polyvinylidene fluoride, polyhexafluoropropylene, polyethylene, polypropylene, polyvinyl chloride, polyvinyl chloride, polystyrene, and polybutadiene, and / or the vinyl polymers include one or more of polyacrylic acid, polymethyl acrylate, and polyacrylonitrile.

8. The isolation member according to claim 1, characterized in that, The volume average particle size Dv50 of the second inorganic particle is 0.5 μm to 3 μm.

9. The isolation member according to claim 1, characterized in that, The first inorganic particle and the second inorganic particle each independently include one or more of the following: boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silicon dioxide, tin dioxide, titanium dioxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, cerium oxide, zirconium titanate, barium titanate, and magnesium fluoride.

10. The separator according to claim 1, characterized in that, At least a portion of the first support portion is embedded in the base portion; and / or, At least a portion of the second support portion is embedded in the base portion.

11. A cylindrical battery cell, characterized in that, It includes a housing and an electrode assembly, the electrode assembly being housed within the housing; The electrode assembly includes a positive electrode, a negative electrode, and an isolator as described in any one of claims 1 to 10, wherein the isolator is used to isolate the positive electrode and the negative electrode, the positive electrode, the negative electrode, and the isolator are wound along a winding direction, and in the wound state, the first support portion is compressed, and the second support portion does not protrude from the first support portion.

12. The cylindrical battery cell according to claim 11, characterized in that, A gap is formed between the positive electrode and the negative electrode, the gap extends along the winding direction, and the gap has a winding start gap and a winding end gap along the winding direction. The minimum value L1 of the winding start gap and the maximum value L2 of the winding end gap satisfy: L2-L1≤10μm.

13. A method for manufacturing a cylindrical battery cell, characterized in that, include: A separator is provided, the separator comprising a porous base membrane and a coating, the coating comprising a substrate, a plurality of first support portions and a plurality of second support portions, the substrate being disposed on the surface of the porous base membrane, at least a portion of the first support portions protruding from the substrate, at least a portion of the second support portions protruding from the substrate, the average protrusion height of the plurality of first support portions being greater than the average protrusion height of the second support portions, the first support portions comprising at least one organic particle, the second support portions comprising at least one first inorganic particle, the substrate comprising second inorganic particles, the volume average particle size Dv50 of the second inorganic particles being less than the volume average particle size Dv50 of the first inorganic particles, the organic particles comprising 10% to 20% of the mass of the coating, the first inorganic particles comprising 10% to 20% of the mass of the coating, and the second inorganic particles comprising 60% to 75% of the mass of the coating; The positive electrode, the negative electrode, and the separator are wound along the winding direction to form an electrode assembly. The separator is used to isolate the positive electrode and the negative electrode. In the winding state, the first support portion of the separator is compressed, and the second support portion does not protrude from the first support portion. Place the electrode assembly into the housing.

14. A battery device, characterized in that, It includes multiple cylindrical battery cells as described in claim 11 or 12.

15. An electrical appliance, characterized in that, Includes a cylindrical battery cell as claimed in claim 11 or 12 or a battery device as claimed in claim 14, wherein the cylindrical battery cell or the battery device is used to store or provide electrical energy.

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