Cylindrical battery monomer, battery device and power utilization device

Abstract

The utility model provides a cylindrical battery cell, a battery device and an electric device. The single cylindrical battery comprises an electrode assembly, the electrode assembly comprises a first pole piece, a second pole piece and a separator, and the first pole piece, the separator and the second pole piece are wound. The separator comprises a base material and an insulating layer arranged on the surface of the base material. And a layer gap is formed between the adjacent first pole piece and second pole piece along the radial direction of the electrode assembly in the section passing through the winding axis of the electrode assembly. And the width of the layer gap is the difference between the distance between the opposite surfaces of the first pole piece and the second pole piece and the thickness of the base material. Among the N layer gaps located on the same side of the winding axis, the average value of the widths of five outward continuous layer gaps starting from the layer gap closest to the winding axis is L1. From one layer gap farthest from the winding axis, the average value of the widths of five continuous layer gaps inward is L2, and 0 < = L1-L2 < = 10 [mu] m is satisfied. The cylindrical battery monomer is relatively long in service life.

Description

Technical Field

[0001] This application relates to the field of batteries, and more specifically, to a cylindrical battery cell, a battery device, and an electrical device. Background Technology

[0002] Batteries are widely used in the new energy field, such as in electric vehicles and new energy vehicles, which have become a new trend in the automotive industry. The development of battery technology must consider multiple design factors simultaneously, such as energy density, discharge capacity, and charge / discharge rate. Additionally, battery cycle life must be considered. However, currently, the cycle life of batteries is relatively short. Utility Model Content

[0003] The purpose of this application is to provide a cylindrical battery cell, a battery device, and an electrical device, which aims to improve the problem of poor battery life in related technologies.

[0004] In a first aspect, embodiments of this application provide a cylindrical battery cell, the cylindrical battery cell including an electrode assembly, the electrode assembly including a first electrode, a second electrode, and a separator, the first electrode and the second electrode having opposite polarities, the first electrode, the separator, and the second electrode being wound together, the separator including a substrate and an insulating layer, the insulating layer being disposed on the surface of the substrate; in a cross section passing through the winding axis of the electrode assembly, along the radial direction of the electrode assembly, adjacent first electrodes and second electrodes have a layer gap, the width of the layer gap being the difference between the distance between the opposing surfaces of the first electrode and the second electrode and the thickness of the substrate, among N layer gaps located on the same side of the winding axis, starting from the layer gap closest to the winding axis, the average width of the five consecutive layer gaps outward is L1, and starting from the layer gap furthest from the winding axis, the average width of the five consecutive layer gaps inward is L2, satisfying: 0≤|L1-L2|≤10μm, N≥10 and being an integer.

[0005] In the above technical solution, L1 represents the width of the inner ring gap of the electrode assembly, and L2 represents the width of the outer ring gap of the electrode assembly. When 0≤|L1-L2|≤10μm, the difference between the width of the inner ring gap and the width of the outer ring gap of the electrode assembly is small, that is, the width of the inner ring gap and the width of the outer ring gap of the electrode assembly are approximately the same. The consistency between the inner ring gap and the outer ring gap of the electrode assembly is good. On the one hand, when the electrode assembly expands, the expansion space of the inner ring electrode and the expansion space of the outer ring electrode are approximately the same, which helps to reduce the difference in the degree of expansion between the inner ring electrode and the outer ring electrode, and helps to reduce the risk of stress concentration when the first electrode and / or the second electrode expands, reduce the risk of active material layer shedding, and reduce the risk of the first electrode and / or the second electrode breaking. On the other hand, it helps to make the electrolyte wetting more sufficient, reduce the risk of lithium plating, and help to extend the life of the cylindrical battery cell.

[0006] As an optional technical solution in this application embodiment, 0≤|L1-L2|≤3μm.

[0007] In the above technical solution, when 0≤|L1-L2|≤3μm, the difference between the width of the inner ring gap and the width of the outer ring gap of the electrode assembly is smaller, and the consistency between the inner and outer ring gaps of the electrode assembly is better. On the one hand, when the electrode assembly expands, the better consistency between the expansion space of the inner and outer ring electrodes is more conducive to reducing the difference in the degree of expansion between the inner and outer ring electrodes, which helps to further reduce the risk of stress concentration when the first and / or second electrodes expand, reduce the risk of active material layer shedding, and reduce the risk of breakage of the first and / or second electrodes. On the other hand, it helps to make the electrolyte wetting more sufficient, reduce the risk of lithium plating, and extend the life of the cylindrical battery cell.

[0008] As an optional technical solution in this application embodiment, the insulating member includes a first part located between the first electrode and the second electrode. In a cross section perpendicular to the winding axis of the electrode assembly, the maximum thickness of the first part is H1, and the minimum thickness of the first part is H2, satisfying: 0≤H1-H2≤2μm.

[0009] In the above technical solution, the width of the interlayer gap is highly correlated with the thickness of the first part. When the thickness of the first part is large, the width of the interlayer gap is also correspondingly large. When the thickness of the first part is small, the width of the interlayer gap is also correspondingly small. When 0≤H1-H2≤2μm, the difference between the maximum thickness and the minimum thickness of the first part is small, which helps to make the width of the inner interlayer gap of the electrode assembly approximately the same as the width of the outer interlayer gap of the electrode assembly, resulting in good consistency between the inner and outer interlayer gaps of the electrode assembly.

[0010] As an optional technical solution in this application embodiment, 0≤H1-H2≤1μm.

[0011] In the above technical solution, when 0≤H1-H2≤1μm, the difference between the maximum thickness and the minimum thickness of the first part is smaller, which is beneficial to make the width of the inner ring gap of the electrode assembly and the width of the outer ring gap of the electrode assembly approximately the same, and the consistency between the inner ring gap and the outer ring gap of the electrode assembly is better.

[0012] As an optional technical solution in this application embodiment, the insulating member includes a first portion located between the first electrode and the second electrode, and the compaction density of the insulating layer of the first portion gradually decreases along the winding direction of the electrode assembly.

[0013] In the above technical solution, during the manufacturing of the separator, the thickness of the insulating layer can be gradually reduced along the length of the separator from one end to the other. When winding the first electrode, the separator, and the second electrode, the thicker portion of the insulating layer of the separator is wound first, followed by the thinner portion. This results in the thicker portion of the insulating layer being located in the inner ring of the electrode assembly, and the thinner portion in the outer ring. Because the inner ring of the electrode assembly experiences greater pressure and the outer ring experiences less pressure, after winding, the compaction density of the insulating layer in the inner ring of the first part is greater, and the compaction density in the outer ring is smaller. This results in a smaller difference between the maximum and minimum thickness of the first part, which helps to make the width of the gap between the inner and outer rings of the electrode assembly approximately the same, resulting in better consistency between the gaps.

[0014] As an optional technical solution in this application embodiment, along the extension direction of the winding axis of the electrode assembly, the first electrode extends beyond the second electrode, the first electrode has a first end, and the insulating member includes a second portion extending beyond the first end. Along the winding direction of the electrode assembly, the thickness of the insulating layer in the second portion gradually decreases.

[0015] In the above technical solution, during the manufacturing of the separator, the thickness of the insulating layer can be gradually reduced along the length of the separator from one end to the other. Because the first part is located between the first and second electrodes, the insulating layer of the first part is compressed by the first and second electrodes, causing the compaction density of the insulating layer of the first part to gradually decrease along the winding direction of the electrode assembly. Along the extension direction of the winding axis of the electrode assembly, the second part extends beyond the first end of the first electrode. The second part is less susceptible to compression by the first and second electrodes, the insulating layer of the second part is less easily compressed, and the thickness of the insulating layer of the second part gradually decreases along the winding direction of the electrode assembly.

[0016] As an optional technical solution in this application embodiment, the compression modulus of the isolation component is greater than or equal to 10 GPa.

[0017] In the above technical solution, when the compressive modulus of the isolator is greater than or equal to 10 GPa, the isolator has strong pressure resistance, which makes the compression amount of the part of the isolator located in the inner ring of the electrode assembly approximately the same as the compression amount of the part of the isolator located in the outer ring of the electrode assembly. This makes the difference between the maximum thickness and the minimum thickness of the first part smaller, which is beneficial to make the difference between the maximum thickness and the minimum thickness of the first part smaller. It is also beneficial to make the width of the inner ring layer gap of the electrode assembly approximately the same as the width of the outer ring layer gap of the electrode assembly, and the consistency between the inner ring layer gap and the outer ring layer gap of the electrode assembly is good.

[0018] As an optional technical solution in this application embodiment, the width of the interlayer gap is 2~100μm.

[0019] In the above technical solutions, when the interlayer gap width is greater than or equal to 2 μm, the gap width is relatively large. On the one hand, this facilitates more thorough electrolyte wetting, reduces the risk of lithium plating, and helps extend the lifespan of the cylindrical battery cell. On the other hand, it allows space for electrode expansion, reducing the risk of collapse of the central hole in the electrode assembly. When the interlayer gap width is less than or equal to 100 μm, the gap width is not too large. On the one hand, this shortens the lithium-ion transport path, reducing the risk of lithium plating. On the other hand, it helps improve the energy density of the cylindrical battery cell. Therefore, when the interlayer gap width is 2~100 μm, both the lifespan and energy density of the cylindrical battery cell can be balanced.

[0020] As an optional technical solution in this application embodiment, the width of the interlayer gap is 5~15μm.

[0021] In the above technical solutions, when the interlayer gap width is greater than or equal to 5 μm, the larger gap width is beneficial in two ways. First, it allows for more thorough electrolyte wetting, reducing the risk of lithium plating and extending the lifespan of the cylindrical battery cell. Second, it provides space for electrode expansion, reducing the risk of collapse of the center hole in the electrode assembly. When the interlayer gap width is less than or equal to 15 μm, the gap width is not too large. This is beneficial in two ways: first, it shortens the lithium-ion transport path, reducing the risk of lithium plating; second, it is beneficial in improving the energy density of the cylindrical battery cell. Therefore, when the interlayer gap width is 5~15 μm, it is possible to better balance the lifespan and energy density of the cylindrical battery cell.

[0022] As an optional technical solution in this application embodiment, L2≤15μm.

[0023] In the above technical solution, when L2≤15μm, the width of the gap between the outer layers of the electrode assembly is relatively small. On the one hand, this helps to shorten the lithium-ion transport path and reduce the risk of lithium plating. On the other hand, it helps to improve the energy density of the cylindrical battery cell.

[0024] As an optional technical solution in this application embodiment, L2≤10μm.

[0025] In the above technical solution, when L2 ≤ 10 μm, the width of the outer ring gap of the electrode assembly is smaller. On the one hand, this is more conducive to shortening the lithium-ion transport path and reducing the risk of lithium plating. On the other hand, it is more conducive to improving the energy density of the cylindrical battery cell.

[0026] As an optional technical solution in this application embodiment, L1≥5μm.

[0027] In the above technical solution, when L1≥5μm, the width of the inner layer gap of the electrode assembly is relatively large. On the one hand, this facilitates more thorough electrolyte wetting, reduces the risk of lithium plating, and helps extend the life of the cylindrical battery cell. On the other hand, it allows space for the expansion of the electrode sheet, reducing the risk of collapse of the central hole of the electrode assembly.

[0028] As an optional technical solution in this application embodiment, L1≥8μm.

[0029] In the above technical solution, when L1 ≥ 8 μm, the width of the inner layer gap of the electrode assembly is larger. On the one hand, this facilitates more thorough electrolyte wetting, reduces the risk of lithium plating, and helps extend the life of the cylindrical battery cell. On the other hand, it allows for more space for electrode expansion, reducing the risk of collapse of the central hole of the electrode assembly.

[0030] Secondly, embodiments of this application also provide a battery device, which includes the aforementioned cylindrical battery cell.

[0031] Thirdly, embodiments of this application also provide an electrical device, the electrical device including the above-mentioned cylindrical battery cell, the cylindrical battery cell being used to provide electrical energy to the electrical device. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0034] Figure 2 Exploded views of battery devices provided in some embodiments of this application;

[0035] Figure 3 Exploded views of cylindrical battery cells provided in some embodiments of this application;

[0036] Figure 4 This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application;

[0037] Figure 5 for Figure 4 A cross-sectional view at position AA in the middle;

[0038] Figure 6 Partial cross-sectional view of an electrode assembly provided in some embodiments of this application;

[0039] Figure 7 Partial cross-sectional view of an electrode assembly provided for other embodiments of this application.

[0040] Icons: 10-Box body; 11-First box body; 12-Second box body; 20-Cylindrical battery cell; 21-Outer casing; 211-Housing casing; 212-End cap; 22-Electrode assembly; 221-Main body; 2211-First electrode; 22111-First current collector; 22112-First active material layer; 22113-First end; 2212-Second electrode; 22121-Second current collector; 22122-Second active material layer; 2213- 22131 - Separator; 22132 - Insulating layer; 22133 - First part; 22134 - Second part; 2214 - Winding axis; 2215 - Layer gap; 222 - Tab; 2221 - First tab; 2222 - Second tab; 23 - Electrode terminal; 24 - Current collector; 241 - First current collector; 242 - Second current collector; 100 - Battery device; 200 - Controller; 300 - Motor; 1000 - Vehicle. Detailed Implementation

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0046] 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.

[0047] In this application, "multiple" means two or more (including two).

[0048] In this embodiment of the application, the cylindrical battery cell can be a secondary battery. A secondary battery refers to a cylindrical battery cell that can be recharged to activate the active materials and continue to be used after it has been discharged.

[0049] Cylindrical battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0050] A cylindrical battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a cylindrical battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0051] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0052] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0053] As an example, the positive electrode current collector can be a foil or a composite current collector. For example, as a foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, 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.).

[0054] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for cylindrical battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as 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 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05At least one of O2 and its modified compounds.

[0055] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0056] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0057] As an example, the negative electrode current collector can be a foil, a foamed metal, or a composite current collector. For example, as a foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, or titanium, etc. The foamed metal can be nickel foam, copper foam, aluminum foam, foam alloy, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper 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.).

[0058] As an example, the negative electrode sheet may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0059] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0060] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in cylindrical battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for cylindrical battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0061] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0062] In some embodiments, the separator is a separator membrane. The separator membrane can be a multilayer composite film, and the separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0063] In some embodiments, the cylindrical battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be a liquid electrolyte, which includes an electrolyte salt and a solvent.

[0064] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0065] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0066] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0067] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by winding.

[0068] In some implementations, the electrode assembly has tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0069] In some embodiments, the cylindrical battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0070] The battery device mentioned in the embodiments of this application may include one or more cylindrical battery cell assemblies for providing voltage and capacity. A cylindrical battery cell assembly may include multiple cylindrical battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0071] In some embodiments, a cylindrical battery cell assembly is typically formed by arranging multiple cylindrical battery cells; as an example, a cylindrical battery cell assembly can be a battery module, which is formed by arranging and fixing multiple cylindrical battery cells to form an independent module.

[0072] As an example, a battery module can be formed by bundling multiple cylindrical battery cells together with cable ties.

[0073] In some embodiments, the battery device may be a battery pack, which may include a housing and one or more cylindrical battery cell assemblies housed within the housing.

[0074] As an example, a cylindrical battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0075] As an example, cylindrical battery cell assemblies can also be housed in a housing by directly fixing multiple cylindrical battery cells to the housing.

[0076] As an example, the enclosure may include a first enclosure body and a second enclosure body. The first enclosure body and the second enclosure body are fastened together to form a closed space inside the enclosure to house the cylindrical battery cell assembly. Here, "closed" refers to covering or closing, which can be either sealed or unsealed. The first enclosure body may be a top cover or a bottom plate.

[0077] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the cylindrical battery cells.

[0078] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0079] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0080] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0081] The development of battery technology must consider multiple design factors simultaneously, such as energy density, discharge capacity, and charge / discharge rate. Additionally, cycle life must be considered. However, current battery cycle life is relatively short.

[0082] For wound electrode assemblies, there is a gap between adjacent positive and negative electrode sheets along the radial direction of the electrode assembly. The width of the gap is the difference between the distance between the opposing surfaces of the positive and negative electrode sheets and the thickness of the substrate of the separator. In related technologies, the gap gradually increases from the inner ring to the outer ring along the radial direction of the electrode assembly; that is, the gap is small in the inner ring and large in the outer ring. The significant difference between the width of the outer ring gap and the width of the inner ring gap indicates poor consistency between them. On the one hand, the difference in expansion between the inner and outer ring electrodes can lead to localized stress concentration, accelerating the shedding of active material and electrode breakage. On the other hand, it results in insufficient electrolyte wetting, making lithium plating more likely and leading to a shorter lifespan for the cylindrical battery cells.

[0083] Therefore, this application provides a cylindrical battery cell, which includes an electrode assembly comprising a first electrode, a second electrode, and a separator. The first and second electrodes have opposite polarities, and the first electrode, separator, and second electrode are wound together. The separator includes a substrate and an insulating layer, with the insulating layer disposed on the surface of the substrate. In a cross-section passing through the winding axis of the electrode assembly, a gap exists between adjacent first and second electrodes along the radial direction of the electrode assembly. The width of the gap is the difference between the distance between the opposing surfaces of the first and second electrodes and the thickness of the substrate. Among N gaps located on the same side of the winding axis, the average width of the five consecutive gaps extending outward from the gap closest to the winding axis is L1. The average width of the five consecutive gaps extending inward from the gap furthest from the winding axis is L2, satisfying: 0 ≤ |L1 - L2| ≤ 10 μm. N ≥ 10 and is an integer.

[0084] L1 represents the width of the inner ring gap of the electrode assembly, and L2 represents the width of the outer ring gap. When 0 ≤ |L1-L2| ≤ 10 μm, the difference between the width of the inner ring gap and the width of the outer ring gap of the electrode assembly is small, meaning that the widths of the inner and outer ring gaps are approximately the same. This good consistency between the inner and outer ring gaps of the electrode assembly has several advantages. Firstly, when the electrode assembly expands, the expansion space of the inner and outer ring electrodes is approximately the same, which helps to reduce the difference in the degree of expansion between the inner and outer ring electrodes. This reduces the risk of stress concentration when the first and / or second electrodes expand, lowers the risk of active material layer shedding, and reduces the risk of breakage of the first and / or second electrodes. Secondly, it allows for more thorough electrolyte wetting, reduces the risk of lithium plating, and extends the lifespan of the cylindrical battery cell.

[0085] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use cylindrical battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0086] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0087] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. A battery device 100 is disposed inside the vehicle 1000, and the battery device 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000.

[0088] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0089] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0090] Please refer to Figure 2 , Figure 2This is an exploded view of a battery device 100 provided in some embodiments of this application. The battery device 100 may include a housing 10 and cylindrical battery cells 20, the housing 10 being used to house the cylindrical battery cells 20.

[0091] The housing 10 has an enclosed space inside for accommodating the cylindrical battery cells 20. The housing 10 can have various structures. In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, which are interlocked. The first housing body 11 and the second housing body 12 can have various shapes, such as cuboids or cylinders. The first housing body 11 can be a hollow structure open on one side, and the second housing body 12 can also be a hollow structure open on one side. The open side of the second housing body 12 interlocks with the open side of the first housing body 11, thus forming a housing 10 with an enclosed space. Alternatively, the first housing body 11 can be a hollow structure open on one side, and the second housing body 12 can be a plate-like structure, with the second housing body 12 interlocked with the open side of the first housing body 11, thus forming a housing 10 with an accommodating chamber.

[0092] In the battery device 100, there can be one or more cylindrical battery cells 20. If there are multiple cylindrical battery cells 20, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that the multiple cylindrical battery cells 20 are connected in both series and parallel. Alternatively, multiple cylindrical battery cells 20 can be first connected in series, in parallel, or in a mixed configuration to form a battery module, and then the multiple battery modules can be connected in series, in parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10. Another option is that all the cylindrical battery cells 20 can be directly connected in series, in parallel, or in a mixed configuration, and then the whole composed of all the cylindrical battery cells 20 is housed within the housing 10.

[0093] In some embodiments, the battery device 100 may further include a busbar component, through which multiple cylindrical battery cells 20 can be electrically connected to each other to achieve series, parallel, or mixed connection of the multiple cylindrical battery cells 20. The busbar component may be a metal conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0094] Please refer to Figure 3 , Figure 4 , Figure 5 and Figure 6 , Figure 3 An exploded view of a cylindrical battery cell 20 provided in some embodiments of this application. Figure 4 This is a schematic diagram of the structure of the electrode assembly 22 provided in some embodiments of this application. Figure 5 for Figure 4 A cross-sectional view at position AA. Figure 6This is a partial cross-sectional view of an electrode assembly 22 provided in some embodiments of this application. Embodiments of this application provide a cylindrical battery cell 20, which includes an electrode assembly 22. The electrode assembly 22 includes a first electrode 2211, a second electrode 2212, and a separator 2213. The first electrode 2211 and the second electrode 2212 have opposite polarities, and the first electrode 2211, the separator 2213, and the second electrode 2212 are wound together. The separator 2213 includes a substrate 22131 and an insulating layer 22132, the insulating layer 22132 being disposed on the surface of the substrate 22131. In a cross-section passing through the winding axis 2214 of the electrode assembly 22, along the radial direction of the electrode assembly 22, adjacent first electrodes 2211 and second electrodes 2212 have a layer gap 2215. The width of the layer gap 2215 is the difference between the distance between the opposing surfaces of the first electrode 2211 and the second electrode 2212 and the thickness of the substrate 22131. Among the N interlayer gaps 2215 located on the same side of the winding axis 2214, the average width of the five consecutive interlayer gaps 2215 extending outward from the one closest to the winding axis 2214 is L1. The average width of the five consecutive interlayer gaps 2215 extending inward from the one furthest from the winding axis 2214 is L2, satisfying: 0 ≤ |L1 - L2| ≤ 10 μm, and N ≥ 10 and is an integer.

[0095] Cylindrical battery cell 20 refers to the smallest unit that makes up battery device 100.

[0096] The cylindrical battery cell 20 includes a housing 21 and an electrode assembly 22, the electrode assembly 22 being housed within the housing 21. The housing 21 includes a casing 211 and an end cap 212. The casing 211 has a receiving space with an opening at one end for accommodating the electrode assembly 22. The end cap 212 is connected to the casing 211 and closes the opening.

[0097] End cap 212 refers to a component that covers the opening of housing 211 to isolate the internal environment of cylindrical battery cell 20 from the external environment. The shape of end cap 212 can be adapted to the shape of housing 211 to fit it. Optionally, end cap 212 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that end cap 212 is less prone to deformation under pressure and impact, giving cylindrical battery cell 20 higher structural strength and improved reliability. The material of end cap 212 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0098] The housing 211 is a component used to mate with the end cap 212 to form the internal environment of the cylindrical battery cell 20. This internal environment can accommodate the electrode assembly 22, electrolyte, and other components. The housing 211 and the end cap 212 can be independent components. An opening can be provided on the housing 211, and the end cap 212 can be used to close the opening to form the internal environment of the cylindrical battery cell 20. Alternatively, the end cap 212 and the housing 211 can be integrated. Specifically, the end cap 212 and the housing 211 can form a common mating surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 211, the end cap 212 closes the housing 211. The housing 211 of the cylindrical battery cell 20 is cylindrical in shape. The material of the housing 211 can be, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0099] In an embodiment where an opening is formed at one end of the housing 211, one end cap 212 may be provided accordingly. In an embodiment where openings are formed at opposite ends of the housing 211, two end caps 212 may be provided accordingly, with the two end caps 212 respectively closing the two openings of the housing 211, and the two end caps 212 and the housing 211 together defining the receiving space.

[0100] Electrode assembly 22 is the component in the cylindrical battery cell 20 where electrochemical reactions occur. The housing 211 may contain one or more electrode assemblies 22. The electrode assembly 22 is mainly formed by winding positive and negative electrode sheets, and typically a separator 2213 is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body 221 of the electrode assembly 22, while the portions of the positive and negative electrode sheets without active material each constitute a tab 222. The positive and negative tabs may be located together at one end of the main body 221 or separately at both ends of the main body 221. During the charging and discharging process of the battery device 100, the positive and negative active materials react with the electrolyte.

[0101] The cylindrical battery cell 20 includes electrode terminals 23, which are disposed on the housing 21 (e.g., the wall of the housing 211 opposite to the end cap 212). The electrode terminals 23 are used for electrical connection with the tabs 222 of the electrode assembly 22 to input or output electrical energy of the cylindrical battery cell 20. The housing 21 is provided with lead-out holes, and the electrode terminals 23 are mounted in the lead-out holes.

[0102] Electrode terminal 23 and tab 222 can be directly connected, for example, by welding electrode terminal 23 to tab 222. Electrode terminal 23 and tab 222 can also be indirectly connected, for example, by connecting electrode terminal 23 and tab 222 indirectly through current collector 24. Current collector 24 can be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc. In some embodiments, there is one electrode terminal 23, one tab 222 of electrode assembly 22 (one of the positive tab and the negative tab) can be electrically connected to electrode terminal 23, and the other tab 222 of electrode assembly 22 (the other of the positive tab and the negative tab) can be electrically connected to housing 21.

[0103] As an example, such as Figure 3 and Figure 4 As shown, the housing 211 has an opening at only one end, and there is one end cap 212 covering the opening of the housing 211. Electrode terminals 23 are provided on the walls of the housing 211 opposite to the end cap 212. The electrode assembly 22 has tabs 222 at both ends. The tabs 222 at both ends of the electrode assembly 22 are a first tab 2221 and a second tab 2222, respectively. One of the first tab 2221 and the second tab 2222 is a positive tab, and the other is a negative tab. The electrode terminal 23 is electrically connected to the first tab 2221 through a first current collector 241, and the end cap 212 is electrically connected to the second tab 2222 through a second current collector 242.

[0104] Please refer to Figure 4 ,exist Figure 4 In the diagram, to facilitate the distinction between the first electrode 2211, the second electrode 2212, and the spacer 2213, the first electrode 2211 is represented by a thin solid line, the second electrode 2212 by a thick solid line, and the spacer 2213 by a dashed line. It should be noted that the thin solid lines, thick solid lines, and dashed lines are only for ease of distinction between the first electrode 2211, the second electrode 2212, and the spacer 2213, and do not represent any other meaning.

[0105] One of the first electrode 2211 and the second electrode 2212 is the positive electrode as described above, and the other of the first electrode 2211 and the second electrode 2212 is the negative electrode as described above. For example, when the first electrode 2211 is the positive electrode, the second electrode 2212 is the negative electrode. Or, for example, when the first electrode 2211 is the negative electrode, the second electrode 2212 is the positive electrode.

[0106] The first electrode 2211 includes a first current collector 22111 and a first active material layer 22112. The first active material layer 22112 is disposed on at least one side of the first current collector 22111 along its thickness direction. For example, in some embodiments, the first active material layer 22112 is disposed on one surface of the first current collector 22111 along its thickness direction. In other embodiments, the first active material layer 22112 is disposed on both opposite surfaces of the first current collector 22111 along its thickness direction. Please refer to... Figure 6 In the embodiment shown in the figure, a first active material layer 22112 is provided on both opposite surfaces of the first current collector 22111 along its thickness direction. When the first electrode 2211 is a positive electrode, the first current collector 22111 is a positive current collector, and the first active material layer 22112 is a positive active material layer, which includes the aforementioned positive active material. When the first electrode 2211 is a negative electrode, the first current collector 22111 is a negative current collector, and the first active material layer 22112 is a negative active material layer, which includes the aforementioned negative active material.

[0107] The second electrode 2212 includes a second current collector 22121 and a second active material layer 22122. The second active material layer 22122 is disposed on at least one side of the second current collector 22121 along its thickness direction. For example, in some embodiments, the second active material layer 22122 is disposed on one surface of the second current collector 22121 along its thickness direction. In other embodiments, the second active material layer 22122 is disposed on both opposite surfaces of the second current collector 22121 along its thickness direction. Please refer to... Figure 6 In the embodiment shown in the figure, a second active material layer 22122 is provided on both opposite surfaces of the second current collector 22121 along its thickness direction. When the second electrode 2212 is a positive electrode, the second current collector 22121 is a positive current collector, and the second active material layer 22122 is a positive active material layer, comprising the aforementioned positive active material. When the second electrode 2212 is a negative electrode, the second current collector 22121 is a negative current collector, and the second active material layer 22122 is a negative active material layer, comprising the aforementioned negative active material.

[0108] The separator 2213 is an insulating structure disposed between the first electrode 2211 and the second electrode 2212. The separator 2213 serves to insulate and isolate the first electrode 2211 and the second electrode 2212, reducing the risk of short circuit due to contact between the first electrode 2211 and the second electrode 2212, while allowing active ions to pass through. The separator 2213 includes a substrate 22131 and an insulating layer 22132. Along the thickness direction of the substrate 22131, the insulating layer 22132 is disposed on at least one side of the substrate 22131. For example, in some embodiments, the insulating layer 22132 is disposed on one surface of the substrate 22131 along its thickness direction. In other embodiments, the insulating layer 22132 is disposed on both opposite surfaces of the substrate 22131 along its thickness direction. Please refer to... Figure 6 In the embodiment shown in the figure, an insulating layer 22132 is provided on both surfaces of the substrate 22131 that are disposed opposite to each other along the thickness direction of the substrate 22131.

[0109] The material of the substrate 22131 may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

[0110] The material of the insulating layer 22132 includes at least one of aluminum oxide, silicon oxide, boehmite, barium sulfate, zirconium oxide, silicon oxide, magnesium oxide, zinc oxide, and tin oxide.

[0111] In some embodiments, the compressive modulus of the insulating layer 22132 is less than that of the substrate 22131, making the insulating layer 22132 more easily compressed than the substrate 22131.

[0112] The first electrode 2211, the separator 2213, and the second electrode 2212 are wound together to form an electrode assembly 22, that is, the electrode assembly 22 is a wound electrode assembly.

[0113] The radial direction of the electrode assembly 22 can be represented by the diameter or radius of the outer casing 21 of the cylindrical battery cell 20. Please refer to... Figure 6 The radial direction of electrode assembly 22 can be the Y direction as shown in the figure.

[0114] Within a cross-section passing through the winding axis 2214 of the electrode assembly 22, along the radial direction of the electrode assembly 22, adjacent first electrode plates 2211 and second electrode plates 2212 have interlayer gaps 2215. The interlayer gaps 2215 include a first gap and a second gap. The first gap is the gap between the first electrode plate 2211 and the substrate 22131 of the spacer 2213 located between the first electrode plate 2211 and the second electrode plate 2212. The second gap is the gap between the second electrode plate 2212 and the substrate 22131 of the spacer 2213 located between the first electrode plate 2211 and the second electrode plate 2212.

[0115] The width of the interlayer gap 2215 is the difference between the distance between the opposing surfaces of the first electrode 2211 and the second electrode 2212 and the thickness of the substrate 22131. Please refer to... Figure 6 Let L3 be the distance between the opposing surfaces of the first electrode 2211 and the second electrode 2212, D be the thickness of the substrate 22131, and X be the width of the interlayer gap 2215. Then X = L3 - D. Alternatively, the width of the interlayer gap 2215 can be obtained by measuring the widths of the first gap and the second gap and summing the widths of the first gap and the second gap.

[0116] When measuring L3 and D, an image of a cross section perpendicular to the winding axis 2214 of the electrode assembly 22 can be obtained by CT. In this image, a ray is drawn outward from the winding axis 2214, and L3 and D are measured on this ray. The width of the interlayer gap 2215 can then be calculated, and L1 and L2 can be measured and calculated in this way.

[0117] Within the cross-section passing through the winding axis 2214 of the electrode assembly 22, among all interlayer gaps 2215 located on the same side of the winding axis 2214, the average width of the five consecutive interlayer gaps 2215 extending outward from the one closest to the winding axis 2214 is L1, and the average width of the five consecutive interlayer gaps 2215 extending inward from the one furthest from the winding axis 2214 is L2. Please refer to... Figure 6 "All interlayer gaps 2215 located on the same side of the winding axis 2214" can refer to all interlayer gaps 2215 located on the left side of the winding axis 2214 or all interlayer gaps 2215 located on the right side of the winding axis 2214. Here, we will take all interlayer gaps 2215 located on the right side of the winding axis 2214 as an example. When the thickness of the substrate 22131 remains constant, the width of the interlayer gap 2215 closest to the winding axis 2214 is: L 31 -D, counting to the right, the widths of the remaining four interlayer gaps 2215 are as follows: L 32 -D、L 33 -D、L 34 -D、L 35 -D. Then L1 = (L 31 -D+ L 32 -D+L 33 -D+L 34 -D+L 35 -D) / 5. The width of the interlayer gap 2215 furthest from the winding axis 2214 is: L 36 -D, counting to the left, the widths of the remaining four interlayer gaps 2215 are as follows: L 37 -D、L38 -D、L 39 -D、L 40 -D. Then L2 = (L 36 -D+ L 37 -D+L 38 -D+L 39 -D+L 40 -D) / 5.

[0118] |L1-L2| represents the absolute value of the difference between L1 and L2. |L1-L2| can take values ​​of 0, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, etc.

[0119] It should be noted that the number of all interlayer gaps 2215 located on the same side of the winding axis 2214 is greater than or equal to 10.

[0120] To make the technical problems, technical solutions, and beneficial effects solved by the embodiments of this application clearer, the following will provide a more detailed description in conjunction with Comparative Examples 1-2 and Embodiments 1-10. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications. 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.

[0121] Example 1

[0122] The cylindrical battery cells 20 in each embodiment and comparative example were prepared and tested according to the following method.

[0123] I. Preparation of Cylindrical Cell 20

[0124] 1) Preparation of positive electrode sheet

[0125] LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 A positive electrode slurry is prepared in N-methylpyrrolidone (NMP) using O2, conductive agent Super P, and binder polyvinylidene fluoride (PVDF). The solid content of the positive electrode slurry is 50 wt%, and the solid component is LiNi. 0.8 Co 0.1 Mn 0.1 The mass ratio of O2, Super P, and PVDF is 8:1:1. The positive electrode slurry is coated on the upper and lower surfaces of the current collector aluminum foil and dried at 85°C. After cold pressing, the foil is trimmed, cut into sheets, and slit. Then, it is dried under vacuum at 85°C for 4 hours to produce the positive electrode sheet.

[0126] 2) Preparation of negative electrode sheet

[0127] Graphite, conductive agent Super P, thickener carboxymethyl cellulose (CMC), and binder styrene-butadiene rubber (SBR) are mixed evenly in deionized water to prepare a negative electrode slurry. The solid content of the negative electrode slurry is 30wt%, and the mass ratio of graphite, silicon suboxide, Super P, CMC, and binder styrene-butadiene rubber (SBR) in the solid components is 88:7:3:2. The negative electrode slurry is coated on the upper and lower surfaces of the current collector copper foil and dried at 85℃. Then, it is cold-pressed, trimmed, cut into sheets, and slit. Finally, it is dried under vacuum at 120℃ for 12 hours to prepare the negative electrode sheet.

[0128] 3) Preparation of electrolytes

[0129] In an argon atmosphere glove box (H2O < 0.1 ppm, O2 < 0.1 ppm), the thoroughly dried electrolyte salt LiPF6 was dissolved in a mixed solvent (the mixed solvent included ethylene carbonate (EC) and diethyl carbonate (DEC), and ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a mass ratio of 50:50) and mixed evenly to obtain a liquid electrolyte with a concentration of 1 mol / L.

[0130] 4) Preparation of the isolation component 2213

[0131] Using polypropylene as the substrate 22131, an insulating layer 22132 is formed by coating two surfaces of the substrate 22131 that are opposite to each other along the thickness direction of the substrate 22131. The thickness of the substrate remains constant along the length direction of the substrate 22131. During coating, the thickness of the insulating layer 22132 gradually decreases along the length direction of the substrate 22131 from one end to the other, thereby forming the insulating element 2213.

[0132] 5) Preparation of cylindrical battery cell 20

[0133] The positive electrode, separator 2213, and negative electrode are stacked in sequence, with the separator 2213 positioned between the positive and negative electrodes to isolate them. The electrode assembly 22 is then wound up and placed inside an aluminum casing 21. The electrolyte prepared above is injected into the dried casing 21. The process includes encapsulation, settling, formation, shaping, and capacity testing to complete the preparation of the cylindrical battery cell 20.

[0134] Both L1 and L2 were obtained through tomographic scanning and then measured by software.

[0135] The preparation methods of the cylindrical battery cells 20 in Comparative Examples 1-2 and Examples 2-10 are the same as those in Example 1, except that |L1-L2| are different, as shown in Table 1.

[0136] II. Performance Parameter Testing

[0137] 1. Method for measuring the number of cyclic fatigue cycles of a cylindrical battery cell (20).

[0138] The test procedures shall be performed in accordance with the requirements and test methods for cycle life of power batteries for electric vehicles in GB / T 31484-2015.

[0139] III. Test Results

[0140] The experimental results of Comparative Examples 1-2 and Examples 1-10 are shown in Table 1 below:

[0141] Table 1

[0142]

[0143] Please refer to Table 1. As shown in Comparative Examples 1 and 2, when |L1-L2|>10μm, the number of cycles of the cylindrical battery cell 20 is relatively small (less than 2500 cycles).

[0144] Please refer to Table 1. As shown in Examples 1-10, when |L1-L2|≤10μm, the cylindrical battery cell 20 has a higher number of cycle fatigue cycles (all greater than 2500 cycles) and a longer lifespan. Furthermore, when |L1-L2|≤3μm, the cylindrical battery cell 20 has an even higher number of cycle fatigue cycles (all greater than 3300 cycles) and an even longer lifespan.

[0145] L1 represents the width of the inner ring gap of electrode assembly 22, and L2 represents the width of the outer ring gap of electrode assembly 22. When 0≤|L1-L2|≤10μm, the difference between the width of the inner ring gap and the width of the outer ring gap of electrode assembly 22 is small, that is, the width of the inner ring gap and the width of the outer ring gap of electrode assembly 22 are approximately the same. The consistency between the inner ring gap and the outer ring gap of electrode assembly 22 is good. On the one hand, when electrode assembly 22 expands, the expansion space of the inner ring electrode and the expansion space of the outer ring electrode are approximately the same, which helps to reduce the difference in the degree of expansion between the inner ring electrode and the outer ring electrode of electrode assembly 22. This helps to reduce the risk of stress concentration when the first electrode 2211 and / or the second electrode 2212 expands, reduce the risk of active material layer shedding, and reduce the risk of breakage of the first electrode 2211 and / or the second electrode 2212. On the other hand, it helps to make the electrolyte wet more fully, reduce the risk of lithium plating, and help to extend the life of the cylindrical battery cell 20.

[0146] Optionally, 0 ≤ |L1-L2| ≤ 3μm.

[0147] |L1-L2| can take values ​​of 0, 0.2μm, 0.5μm, 0.8μm, 1μm, 1.2μm, 1.5μm, 1.8μm, 2μm, 2.2μm, 2.5μm, 2.8μm, 3μm, etc.

[0148] When 0 ≤ |L1-L2| ≤ 3 μm, the difference between the width of the inner ring gap and the width of the outer ring gap of the electrode assembly 22 is smaller, and the consistency between the inner ring gap and the outer ring gap of the electrode assembly 22 is better. On the one hand, when the electrode assembly 22 expands, the better consistency between the expansion space of the inner ring electrode and the expansion space of the outer ring electrode of the electrode assembly 22 is more conducive to reducing the difference in the degree of expansion between the inner ring electrode and the outer ring electrode of the electrode assembly 22. This is beneficial to further reduce the risk of stress concentration when the first electrode 2211 and / or the second electrode 2212 expands, reduce the risk of active material layer shedding, and reduce the risk of breakage of the first electrode 2211 and / or the second electrode 2212. On the other hand, it is beneficial to make the electrolyte wetting more sufficient, reduce the risk of lithium plating, and extend the life of the cylindrical battery cell 20.

[0149] Please refer to Figure 3 , Figure 4 , Figure 5 and Figure 6In some embodiments, the spacer 2213 includes a first portion 22133 located between the first electrode 2211 and the second electrode 2212. In a cross section perpendicular to the winding axis 2214 of the electrode assembly 22, the maximum thickness of the first portion 22133 is H1, and the minimum thickness of the first portion 22133 is H2, satisfying: 0 ≤ H1 - H2 ≤ 2 μm.

[0150] The first part 22133 is the portion of the spacer 2213 located between the first electrode 2211 and the second electrode 2212. When the first electrode 2211, the spacer 2213, and the second electrode 2212 are wound, the first part 22133 is compressed by pressure.

[0151] In some embodiments, the substrate 22131 of the first portion 22133 is not easily compressed, mainly because the insulating layer 22132 of the first portion 22133 is compressed.

[0152] H1 represents the maximum thickness of the first portion 22133 within a cross-section perpendicular to the winding axis 2214 of the electrode assembly 22. H2 represents the minimum thickness of the first portion 22133 within a cross-section perpendicular to the winding axis 2214 of the electrode assembly 22. It should be noted that H1 and H2 are measured within the same cross-section perpendicular to the winding axis 2214 of the electrode assembly 22. During measurement, an image of the cross-section perpendicular to the winding axis 2214 of the electrode assembly 22 can be obtained using CT, and H1 and H2 can be measured using software.

[0153] H1-H2 can take values ​​of 0, 0.2μm, 0.5μm, 0.8μm, 1μm, 1.2μm, 1.5μm, 1.8μm, 2μm, etc.

[0154] The width of the interlayer gap 2215 is highly correlated with the thickness of the first portion 22133. When the thickness of the first portion 22133 is large, the width of the interlayer gap 2215 is also correspondingly large. When the thickness of the first portion 22133 is small, the width of the interlayer gap 2215 is also correspondingly small. When 0 ≤ H1 - H2 ≤ 2 μm, the difference between the maximum thickness and the minimum thickness of the first portion 22133 is small, which helps to make the width of the inner interlayer gap of the electrode assembly 22 approximately the same as the width of the outer interlayer gap of the electrode assembly 22, resulting in good consistency between the inner and outer interlayer gaps of the electrode assembly 22.

[0155] Optionally, 0 ≤ H1 - H2 ≤ 1 μm.

[0156] H1-H2 can take values ​​of 0, 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, etc.

[0157] When 0≤H1-H2≤1μm, the difference between the maximum thickness and the minimum thickness of the first part 22133 is smaller, which helps to make the width of the inner ring gap of the electrode assembly 22 and the width of the outer ring gap of the electrode assembly 22 approximately the same, and the consistency between the inner ring gap and the outer ring gap of the electrode assembly 22 is better.

[0158] Please refer to Figure 3 , Figure 4 , Figure 5 and Figure 6 In some embodiments, the spacer 2213 includes a first portion 22133 located between the first electrode 2211 and the second electrode 2212. Along the winding direction of the electrode assembly 22, the compaction density of the insulating layer 22132 of the first portion 22133 gradually decreases.

[0159] Please refer to Figure 4 The winding direction of electrode assembly 22 is the Z direction as shown in the figure.

[0160] The formula for calculating compaction density is: Compaction density = Surface density / Material thickness, with units of g / cm³.

[0161] The compaction density of the insulating layer 22132 of the first part 22133 gradually decreases along the winding direction of the electrode assembly 22. The closer to the inner ring of the electrode assembly 22, the greater the compaction density of the insulating layer 22132 of the first part 22133. The closer to the outer ring of the electrode assembly 22, the smaller the compaction density of the insulating layer 22132 of the first part 22133.

[0162] When manufacturing the spacer 2213, the thickness of the substrate 22131 can remain constant along the length of the spacer 2213, while the thickness of the insulating layer 22132 gradually decreases from one end of the spacer 2213 to the other. The substrate 22131 is not easily compressed; it is mainly the insulating layer 22132 that is compressed. When winding the first electrode 2211, the spacer 2213, and the second electrode 2212, the thicker portion of the insulating layer 22132 of the spacer 2213 is wound in first, followed by the thinner portion. This ensures that the thicker portion of the insulating layer 22132 of the spacer 2213 is located in the inner ring of the electrode assembly 22, and the thinner portion is located in the outer ring of the electrode assembly 22. Because the inner ring of the electrode assembly 22 experiences greater pressure and the outer ring experiences less pressure, after winding, the compaction density of the insulating layer 22132 of the first part 22133 located in the inner ring of the electrode assembly 22 is greater, and the compaction density of the insulating layer 22132 of the first part 22133 located in the outer ring of the electrode assembly 22 is smaller. This makes the difference between the maximum thickness and the minimum thickness of the first part 22133 smaller, which helps to make the width of the inner ring layer gap of the electrode assembly 22 and the width of the outer ring layer gap of the electrode assembly 22 approximately the same, and the consistency between the inner ring layer gap and the outer ring layer gap of the electrode assembly 22 is better.

[0163] Please refer to Figure 3 , Figure 4 , Figure 5 and Figure 6 In some embodiments, along the extension direction of the winding axis 2214 of the electrode assembly 22, the first electrode 2211 extends beyond the second electrode 2212. The first electrode 2211 has a first end 22113, and the separator 2213 includes a second portion 22134 extending beyond the first end 22113. Along the winding direction of the electrode assembly 22, the thickness of the insulating layer 22132 of the second portion 22134 gradually decreases.

[0164] Please refer to Figure 5 and Figure 6 The extension direction of the winding axis 2214 of the electrode assembly 22 is the X direction shown in the figure.

[0165] If the first electrode 2211 extends beyond the second electrode 2212 along the winding axis 2214 of the electrode assembly 22, then the first electrode 2211 can be a negative electrode and the second electrode 2212 can be a positive electrode. The negative electrode extends beyond the positive electrode along the winding axis 2214 of the electrode assembly 22 to achieve an overhang design and reduce the risk of lithium plating.

[0166] The first end 22113 is one end of the first electrode 2211 extending along the winding axis 2214 of the electrode assembly 22. The separator 2213 includes a second portion 22134, which is the portion of the separator 2213 extending beyond the first end 22113 along the winding axis 2214 of the electrode assembly 22. The thickness of the insulating layer 22132 of the second portion 22134 gradually decreases along the winding direction of the electrode assembly 22; the closer to the inner ring of the electrode assembly 22, the greater the thickness of the insulating layer 22132 of the second portion 22134; and the closer to the outer ring of the electrode assembly 22, the smaller the thickness of the insulating layer 22132 of the second portion 22134.

[0167] During the manufacturing of the separator 2213, the thickness of the insulating layer 22132 can be gradually reduced along the length of the separator 2213 from one end to the other. Because the first part 22133 is located between the first electrode 2211 and the second electrode 2212, the insulating layer 22132 of the first part 22133 is compressed by the first electrode 2211 and the second electrode 2212, causing the compaction density of the insulating layer 22132 of the first part 22133 to gradually decrease along the winding direction of the electrode assembly 22. Along the extension direction of the winding axis 2214 of the electrode assembly 22, the second part 22134 extends beyond the first end 22113 of the first electrode 2211. The second part 22134 is not easily squeezed by the first electrode 2211 and the second electrode 2212. The insulating layer 22132 of the second part 22134 is not easily compressed. The thickness of the insulating layer 22132 of the second part 22134 gradually decreases along the winding direction of the electrode assembly 22.

[0168] Please refer to Figure 7 , Figure 7 This is a partial cross-sectional view of the electrode assembly 22 provided in some other embodiments of this application. In some other embodiments, the compressive modulus of the spacer 2213 is greater than or equal to 10 GPa.

[0169] Compression modulus is a measure of an object's resistance to compressive deformation. The higher the compression modulus of the spacer 2213, the less easily it is compressed. The lower the compression modulus of the spacer 2213, the more easily it is compressed.

[0170] The compressive modulus of the isolation element 2213 can be 10 GPa, 11 GPa, 12 GPa, 13 GPa, 14 GPa, 15 GPa, etc.

[0171] When the compressive modulus of the isolator 2213 is greater than or equal to 10 GPa, the isolator 2213 has strong pressure resistance, which makes the compression amount of the portion of the isolator 2213 located in the inner ring of the electrode assembly 22 approximately the same as the compression amount of the portion of the isolator 2213 located in the outer ring of the electrode assembly 22. This makes the difference between the maximum thickness and the minimum thickness of the first portion 22133 smaller, which is beneficial to make the width of the inner ring layer gap of the electrode assembly 22 approximately the same as the width of the outer ring layer gap of the electrode assembly 22. The consistency between the inner ring layer gap and the outer ring layer gap of the electrode assembly 22 is good.

[0172] In some embodiments, the width of the interlayer gap 2215 is 2~100μm.

[0173] The width of the interlayer gap 2215 can be 2μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, etc.

[0174] When the width of the interlayer gap 2215 is greater than or equal to 2 μm, the relatively large width of the interlayer gap 2215 is beneficial in two ways. First, it allows for more thorough electrolyte wetting, reducing the risk of lithium plating and extending the lifespan of the cylindrical battery cell 20. Second, it provides space for electrode expansion, reducing the risk of collapse of the central hole of the electrode assembly 22. When the width of the interlayer gap 2215 is less than or equal to 100 μm, the width of the interlayer gap 2215 is not too large. First, it shortens the lithium-ion transport path, reducing the risk of lithium plating. Second, it helps to improve the energy density of the cylindrical battery cell 20. Therefore, when the width of the interlayer gap 2215 is 2~100 μm, both the lifespan and energy density of the cylindrical battery cell 20 can be balanced.

[0175] Optionally, the width of the interlayer gap 2215 is 5~15μm.

[0176] The width of the interlayer gap 2215 can be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, etc.

[0177] When the width of the interlayer gap 2215 is greater than or equal to 5 μm, the wider gap 2215 allows for more thorough electrolyte wetting, reducing the risk of lithium plating and extending the lifespan of the cylindrical battery cell 20. It also allows for space for electrode expansion, reducing the risk of collapse of the central hole in the electrode assembly 22. When the width of the interlayer gap 2215 is less than or equal to 15 μm, the gap 2215 is not excessively wide. This further shortens the lithium-ion transport path, reducing the risk of lithium plating, and also improves the energy density of the cylindrical battery cell 20. Therefore, a gap width of 5–15 μm better balances the lifespan and energy density of the cylindrical battery cell 20.

[0178] In some embodiments, L2 ≤ 15 μm.

[0179] L2 can be 15μm, 14μm, 13μm, 12μm, 11μm, 10μm, 9μm, 8μm, 7μm, etc.

[0180] In some embodiments, 5μm≤L2≤15μm.

[0181] When L2 ≤ 15 μm, the width of the gap between the outer layers of the electrode assembly 22 is relatively small. On the one hand, this helps to shorten the lithium-ion transport path and reduce the risk of lithium plating. On the other hand, it helps to improve the energy density of the cylindrical battery cell 20.

[0182] In some embodiments, L2 ≤ 10 μm.

[0183] L2 can be 10μm, 9μm, 8μm, 7μm, 6μm, 5μm, etc.

[0184] When L2 ≤ 10 μm, the width of the outer layer gap of the electrode assembly 22 is smaller. On the one hand, this is more conducive to shortening the lithium-ion transport path and reducing the risk of lithium plating. On the other hand, it is more conducive to improving the energy density of the cylindrical battery cell 20.

[0185] In some embodiments, L1 ≥ 5 μm.

[0186] L1 can be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, etc.

[0187] In some embodiments, 5μm≤L1≤15μm.

[0188] When L1 ≥ 5 μm, the width of the inner layer gap of the electrode assembly 22 is relatively large. On the one hand, this facilitates more thorough electrolyte wetting, reduces the risk of lithium plating, and helps extend the lifespan of the cylindrical battery cell 20. On the other hand, it allows space for the expansion of the electrode sheet, reducing the risk of collapse of the central hole of the electrode assembly 22.

[0189] In some embodiments, L1 ≥ 8 μm.

[0190] L1 can be 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, etc.

[0191] When L1 ≥ 8 μm, the width of the inner layer gap of the electrode assembly 22 is larger. On the one hand, this facilitates more thorough electrolyte wetting, reduces the risk of lithium plating, and helps extend the life of the cylindrical battery cell 20. On the other hand, it allows for more space for electrode expansion, reducing the risk of collapse of the central hole of the electrode assembly 22.

[0192] This application embodiment also provides a battery device 100, which includes the above-described cylindrical battery cell 20.

[0193] This application embodiment also provides an electrical device, which includes the above-mentioned cylindrical battery cell 20, and the cylindrical battery cell 20 is used to provide electrical energy to the electrical device.

[0194] According to some embodiments of this application, please refer to Figures 3-7 .

[0195] This application provides a cylindrical battery cell 20, which includes an electrode assembly 22. The electrode assembly 22 includes a first electrode 2211, a second electrode 2212, and a separator 2213. The first electrode 2211 and the second electrode 2212 have opposite polarities, and the first electrode 2211, the separator 2213, and the second electrode 2212 are wound together. The separator 2213 includes a substrate 22131 and an insulating layer 22132, with the insulating layer 22132 disposed on the surface of the substrate 22131. In a cross-section passing through the winding axis 2214 of the electrode assembly 22, along the radial direction of the electrode assembly 22, adjacent first electrodes 2211 and second electrodes 2212 have a layer gap 2215. The width of the layer gap 2215 is the difference between the distance between the opposing surfaces of the first electrode 2211 and the second electrode 2212 and the thickness of the substrate 22131. Among the N interlayer gaps 2215 located on the same side of the winding axis 2214, the average width of the five consecutive interlayer gaps 2215 extending outward from the one closest to the winding axis 2214 is L1. The average width of the five consecutive interlayer gaps 2215 extending inward from the one furthest from the winding axis 2214 is L2, satisfying: 0 ≤ |L1 - L2| ≤ 10 μm, and N ≥ 10 and are integers. L1 represents the width of the inner interlayer gaps of the electrode assembly 22, and L2 represents the width of the outer interlayer gaps of the electrode assembly 22. When 0 ≤ |L1-L2| ≤ 10 μm, the difference between the width of the inner ring gap and the width of the outer ring gap of the electrode assembly 22 is small, meaning that the width of the inner ring gap and the width of the outer ring gap of the electrode assembly 22 are approximately the same. This good consistency between the inner and outer ring gaps of the electrode assembly 22 has several advantages. Firstly, when the electrode assembly 22 expands, the expansion space of the inner and outer ring electrodes is approximately the same, which helps to reduce the difference in the degree of expansion between the inner and outer ring electrodes. This reduces the risk of stress concentration when the first electrode 2211 and / or the second electrode 2212 expands, lowers the risk of active material layer shedding, and reduces the risk of breakage of the first electrode 2211 and / or the second electrode 2212. Secondly, it facilitates more thorough electrolyte wetting, reduces the risk of lithium plating, and helps extend the lifespan of the cylindrical battery cell 20.

[0196] Optionally, 0 ≤ |L1-L2| ≤ 3 μm. When 0 ≤ |L1-L2| ≤ 3 μm, the difference between the width of the inner ring gap and the width of the outer ring gap of the electrode assembly 22 is smaller, and the consistency between the inner ring gap and the outer ring gap of the electrode assembly 22 is better. On the one hand, when the electrode assembly 22 expands, the consistency between the expansion space of the inner ring electrode and the expansion space of the outer ring electrode of the electrode assembly 22 is better, which is more conducive to reducing the difference in the degree of expansion between the inner ring electrode and the outer ring electrode of the electrode assembly 22. This is beneficial to further reduce the risk of stress concentration when the first electrode 2211 and / or the second electrode 2212 expands, reduce the risk of active material layer shedding, and reduce the risk of breakage of the first electrode 2211 and / or the second electrode 2212. On the other hand, it is beneficial to make the electrolyte wetting more sufficient, reduce the risk of lithium plating, and extend the life of the cylindrical battery cell 20.

[0197] The separator 2213 includes a first portion 22133 located between the first electrode 2211 and the second electrode 2212. In a cross-section perpendicular to the winding axis 2214 of the electrode assembly 22, the maximum thickness of the first portion 22133 is H1, and the minimum thickness is H2, satisfying: 0 ≤ H1 - H2 ≤ 2 μm. The width of the interlayer gap 2215 is highly correlated with the thickness of the first portion 22133; when the thickness of the first portion 22133 is large, the width of the interlayer gap 2215 is correspondingly large. When the thickness of the first portion 22133 is small, the width of the interlayer gap 2215 is correspondingly small. When 0≤H1-H2≤2μm, the difference between the maximum thickness and the minimum thickness of the first part 22133 is small, which helps to make the width of the inner ring gap of the electrode assembly 22 and the width of the outer ring gap of the electrode assembly 22 approximately the same, and the consistency between the inner ring gap and the outer ring gap of the electrode assembly 22 is good.

[0198] In some embodiments, the spacer 2213 includes a first portion 22133 located between the first electrode 2211 and the second electrode 2212, wherein the compaction density of the insulating layer 22132 of the first portion 22133 gradually decreases along the winding direction of the electrode assembly 22. When manufacturing the spacer 2213, the thickness of the insulating layer 22132 can be made to gradually decrease along the length direction of the spacer 2213 from one end to the other. When winding the first electrode 2211, the spacer 2213, and the second electrode 2212, the portion of the insulating layer 22132 with a larger thickness of the spacer 2213 is wound in first, and the portion with a smaller thickness of the insulating layer 22132 is wound in later, such that the portion of the insulating layer 22132 with a larger thickness of the spacer 2213 is located in the inner ring of the electrode assembly 22, and the portion with a smaller thickness of the insulating layer 22132 is located in the outer ring of the electrode assembly 22. Because the inner ring of the electrode assembly 22 experiences greater pressure and the outer ring experiences less pressure, after winding, the compaction density of the insulating layer 22132 of the first part 22133 located in the inner ring of the electrode assembly 22 is greater, and the compaction density of the insulating layer 22132 of the first part 22133 located in the outer ring of the electrode assembly 22 is smaller. This makes the difference between the maximum thickness and the minimum thickness of the first part 22133 smaller, which helps to make the width of the inner ring layer gap of the electrode assembly 22 and the width of the outer ring layer gap of the electrode assembly 22 approximately the same, and the consistency between the inner ring layer gap and the outer ring layer gap of the electrode assembly 22 is better.

[0199] Along the extension direction of the winding axis 2214 of the electrode assembly 22, the first electrode 2211 extends beyond the second electrode 2212. The first electrode 2211 has a first end 22113, and the spacer 2213 includes a second portion 22134 extending beyond the first end 22113. Along the winding direction of the electrode assembly 22, the thickness of the insulating layer 22132 of the second portion 22134 gradually decreases. During the manufacturing of the spacer 2213, along the length of the spacer 2213, the thickness of the insulating layer 22132 can be made to gradually decrease from one end of the spacer 2213 to the other. Because the first portion 22133 is located between the first electrode 2211 and the second electrode 2212, the insulating layer 22132 of the first portion 22133 is compressed by the first electrode 2211 and the second electrode 2212, causing the compaction density of the insulating layer 22132 of the first portion 22133 to gradually decrease along the winding direction of the electrode assembly 22. Along the extension direction of the winding axis 2214 of the electrode assembly 22, the second part 22134 extends beyond the first end 22113 of the first electrode 2211. The second part 22134 is not easily squeezed by the first electrode 2211 and the second electrode 2212. The insulating layer 22132 of the second part 22134 is not easily compressed. The thickness of the insulating layer 22132 of the second part 22134 gradually decreases along the winding direction of the electrode assembly 22.

[0200] In other embodiments, the compressive modulus of the spacer 2213 is greater than or equal to 10 GPa. When the compressive modulus of the spacer 2213 is greater than or equal to 10 GPa, the pressure resistance of the spacer 2213 is stronger, so that the compression amount of the portion of the spacer 2213 located in the inner ring of the electrode assembly 22 is approximately the same as that of the portion of the spacer 2213 located in the outer ring of the electrode assembly 22. This makes the difference between the maximum thickness and the minimum thickness of the first portion 22133 smaller, which is beneficial to make the difference between the maximum thickness and the minimum thickness of the first portion 22133 smaller. This is also beneficial to make the width of the inner ring layer gap of the electrode assembly 22 approximately the same as the width of the outer ring layer gap of the electrode assembly 22, resulting in better consistency between the inner ring layer gap and the outer ring layer gap of the electrode assembly 22.

[0201] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A cylindrical battery cell, characterized in that, include: An electrode assembly includes a first electrode, a second electrode, and a separator. The first electrode and the second electrode have opposite polarities. The first electrode, the separator, and the second electrode are wound together. The separator includes a substrate and an insulating layer. The insulating layer is disposed on the surface of the substrate. Within a cross-section passing through the winding axis of the electrode assembly, along the radial direction of the electrode assembly, there is a gap between adjacent first and second electrodes. The width of the gap is the difference between the distance between the opposing surfaces of the first and second electrodes and the thickness of the substrate. Among the N gaps located on the same side of the winding axis, the average width of the five consecutive gaps outward from the gap closest to the winding axis is L1, and the average width of the five consecutive gaps inward from the gap furthest from the winding axis is L2, satisfying: 0 ≤ |L1 - L2| ≤ 10 μm, N ≥ 10 and is an integer.

2. The cylindrical battery cell according to claim 1, characterized in that, 0≤|L1-L2|≤3μm.

3. The cylindrical battery cell according to claim 1, characterized in that, The insulating element includes a first portion located between the first electrode and the second electrode. In a cross section perpendicular to the winding axis of the electrode assembly, the maximum thickness of the first portion is H1, and the minimum thickness of the first portion is H2, satisfying: 0≤H1-H2≤2μm.

4. The cylindrical battery cell according to claim 3, characterized in that, 0≤H1-H2≤1μm.

5. The cylindrical battery cell according to claim 1, characterized in that, The insulating element includes a first portion located between the first electrode and the second electrode, wherein the compaction density of the insulating layer of the first portion gradually decreases along the winding direction of the electrode assembly.

6. The cylindrical battery cell according to claim 1, characterized in that, Along the extension direction of the winding axis of the electrode assembly, the first electrode extends beyond the second electrode, the first electrode has a first end, and the insulating member includes a second portion extending beyond the first end, wherein the thickness of the insulating layer in the second portion gradually decreases along the winding direction of the electrode assembly.

7. The cylindrical battery cell according to claim 1, characterized in that, The compressive modulus of the isolation element is greater than or equal to 10 GPa.

8. The cylindrical battery cell according to any one of claims 1-7, characterized in that, The width of the interlayer gap is 2~100μm.

9. The cylindrical battery cell according to claim 8, characterized in that, The width of the interlayer gap is 5~15μm.

10. The cylindrical battery cell according to any one of claims 1-7, characterized in that, L2≤15μm.

11. The cylindrical battery cell according to claim 10, characterized in that, L2≤10μm.

12. The cylindrical battery cell according to any one of claims 1-7, characterized in that, L1≥5μm.

13. The cylindrical battery cell according to claim 12, characterized in that, L1≥8μm.

14. A battery device, characterized in that, Includes the cylindrical battery cell according to any one of claims 1-13.

15. An electrical appliance, characterized in that, Includes a cylindrical battery cell according to any one of claims 1-13, the cylindrical battery cell being used to provide electrical energy to the electrical device.

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