Cylindrical battery cell, battery device, and electric device

Abstract

The application provides a cylindrical battery monomer, a battery device and an electric device. The cylindrical battery monomer comprises an electrode assembly, a shell and a protective coating, and the electrode assembly is contained in the shell. The shell comprises an end wall and a side wall, and the side wall is arranged around the end wall. The side wall comprises a first base material and a first corrosion-resistant layer, and the first corrosion-resistant layer is arranged on the outer surface of the first base material. The end wall comprises a second base material and a second corrosion-resistant layer, and the second corrosion-resistant layer is arranged on the outer surface of the second base material. The first base material and the second base material are integrally formed, the first corrosion-resistant layer and the second corrosion-resistant layer are integrally formed, and the material of the first base material and the second base material comprises steel. The end wall is provided with a liquid injection hole, or the end wall is provided with an electrode terminal, and the electrode terminal is provided with a liquid injection hole. The protective coating is at least partially arranged on the outer circumferential surface of the first corrosion-resistant layer. In the axial direction of the cylindrical battery monomer, the protective coating at least extends to one end of the outer circumferential surface of the first corrosion-resistant layer close to the second corrosion-resistant layer. The cylindrical battery monomer has a long 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 lifespan must be considered. However, current battery lifespans are relatively short. Summary of the Invention

[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 short 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, a housing, and a protective coating. The electrode assembly is housed within the housing, the housing including an end wall and a side wall, the side wall surrounding the end wall, the side wall including a first substrate and a first anti-corrosion layer, the first anti-corrosion layer being disposed on the outer surface of the first substrate, the end wall including a second substrate and a second anti-corrosion layer, the second anti-corrosion layer being disposed on the outer surface of the second substrate, the first substrate and the second substrate being integrally formed, the first anti-corrosion layer and the second anti-corrosion layer being integrally formed, the material of the first substrate and the second substrate including steel; the end wall is provided with a liquid injection hole, or the end wall is provided with an electrode terminal, the electrode terminal being provided with a liquid injection hole; the protective coating is at least partially disposed on the outer peripheral surface of the first anti-corrosion layer, along the axial direction of the cylindrical battery cell, the protective coating extending at least to the end of the outer peripheral surface of the first anti-corrosion layer near the second anti-corrosion layer.

[0005] In the above technical solution, the outer shell can be manufactured by stamping, so that the first substrate and the second substrate are integrally formed, and the first anti-corrosion layer and the second anti-corrosion layer are integrally formed. By providing a protective coating on the outer peripheral surface of the first anti-corrosion layer, and extending the protective coating at least to the end of the outer peripheral surface of the first anti-corrosion layer along the axis of the cylindrical battery cell near the second anti-corrosion layer, the protective coating can cover the cracks generated in the first anti-corrosion layer during processing. This helps reduce the risk of electrolyte spilled during electrolyte injection seeping into the first substrate, helps alleviate the rusting phenomenon of the first substrate, and helps improve the lifespan of the cylindrical battery cell.

[0006] As an optional technical solution in this application embodiment, the outer peripheral surface of the first anti-corrosion layer is provided with a recess, and a portion of the protective coating is accommodated in the recess.

[0007] In the above technical solution, by setting a recess on the outer peripheral surface of the first anti-corrosion layer and accommodating a portion of the protective coating within the recess, the recess can restrict the protective coating to a certain extent, which is beneficial to improving the firmness of the protective coating on the sidewall, achieving long-term protection of the sidewall, reducing the risk of the protective coating falling off the outer peripheral surface of the first anti-corrosion layer in a short period of time and causing protective failure, which is beneficial to alleviating the rusting phenomenon of the first substrate and improving the lifespan of the cylindrical battery cell.

[0008] As an optional technical solution in this application embodiment, the outer shell includes a corner wall, the corner wall includes a third substrate and a third anti-corrosion layer, the third anti-corrosion layer is disposed on the outer surface of the third substrate, the material of the third substrate includes steel, the third substrate connects the first substrate and the second substrate, the first substrate, the second substrate and the third substrate are integrally formed, the third anti-corrosion layer connects the first anti-corrosion layer and the second anti-corrosion layer, the first anti-corrosion layer, the second anti-corrosion layer and the third anti-corrosion layer are integrally formed; the outer surface of the third anti-corrosion layer connects the outer surface of the second anti-corrosion layer and the outer peripheral surface of the first anti-corrosion layer, and the protective coating covers at least a portion of the outer surface of the third anti-corrosion layer.

[0009] In the above technical solution, by setting a corner wall that connects the end wall and the side wall, the risk of stress concentration at the connection point of the end wall and the side wall can be reduced. By covering at least a portion of the outer surface of the third anti-corrosion layer with a protective coating, the protective coating can cover cracks generated in the third anti-corrosion layer during processing, which helps reduce the risk of electrolyte spilled during injection seeping into the third substrate, helps alleviate rusting of the third substrate, and helps improve the lifespan of the cylindrical battery cell.

[0010] As an optional technical solution in this application embodiment, the outer surface of the third anti-corrosion layer includes a first end and a second end. The first end is connected to the outer peripheral surface of the first anti-corrosion layer, and the second end is connected to the outer surface of the second anti-corrosion layer. The protective coating includes a first portion disposed on the outer peripheral surface of the first anti-corrosion layer and a second portion disposed on the outer surface of the third anti-corrosion layer. The first portion and the second portion are connected. Along the direction from the first end to the second end on the outer surface of the third anti-corrosion layer, the distance between the outer surface of the second portion and the outer surface of the third anti-corrosion layer gradually decreases.

[0011] In the above technical solution, by making the distance between the outer surface of the second part and the outer surface of the third anti-corrosion layer gradually decrease along the direction of the outer surface of the third anti-corrosion layer from the first end to the second end, it is beneficial to reduce the risk of stress concentration in the second part and the risk of peeling or cracking of the second part in the short term, so as to achieve long-term protection of the corner wall.

[0012] As an optional technical solution in this application embodiment, the protective coating completely covers the outer surface of the third anti-corrosion layer.

[0013] In the above technical solution, by making the protective coating completely cover the outer surface of the third anti-corrosion layer, it is beneficial to improve the protective effect on the third substrate, further alleviate the rusting phenomenon of the third substrate, and improve the life of the cylindrical battery cell.

[0014] As an optional technical solution in this application embodiment, in the axial direction of the cylindrical battery cell, along the direction from the second substrate to the second anti-corrosion layer, the protective coating does not extend beyond the outer surface of the second anti-corrosion layer.

[0015] In the above technical solution, by ensuring that the protective coating does not extend beyond the outer surface of the second anti-corrosion layer along the direction from the second substrate to the second anti-corrosion layer, it is beneficial to reduce the risk of interference between the protective coating and other components, and to reduce the risk of damage to the protective coating. Furthermore, it helps to reduce space occupation and improve the energy density of the cylindrical battery cell.

[0016] As an optional technical solution in this application embodiment, the protective coating includes a first portion disposed on the outer peripheral surface of the first anti-corrosion layer. The first portion includes a first region and a second region. Along the axial direction of the cylindrical battery cell, the first region has a third end and a fourth end opposite to each other. The third end is connected to the second region, and the fourth end extends to one end of the outer peripheral surface of the first anti-corrosion layer near the second anti-corrosion layer. Along the direction from the fourth end to the third end, the distance between the outer surface of the second region and the outer peripheral surface of the first anti-corrosion layer gradually decreases.

[0017] In the above technical solution, by making the distance between the outer surface of the second region and the outer peripheral surface of the first anti-corrosion layer gradually decrease along the direction from the fourth end to the third end, on the one hand, it helps to reduce the risk of stress concentration in the second region and the risk of peeling or cracking in the second region in the short term, thus achieving long-term protection for the sidewall. On the other hand, it allows the insulating film covering the outside of the sidewall to gradually transition from the outer peripheral surface of the first anti-corrosion layer through the second region to the first region, which helps to reduce the risk of the insulating film peeling off.

[0018] As an optional technical solution in this application embodiment, the first region has a first surface that is away from the outer peripheral surface of the first anti-corrosion layer, and the second region has a transition surface that connects the first surface and the outer peripheral surface of the first anti-corrosion layer. The transition surface is an inclined surface.

[0019] In the above technical solution, the insulating film covering the outer sidewall can gradually transition from the outer peripheral surface of the first anti-corrosion layer to the first surface through the transition surface. When the transition surface is inclined, it is more conducive to reducing the risk of the insulating film lifting.

[0020] As an optional technical solution in this application embodiment, the angle between the transition surface and the axis of the cylindrical battery cell is α, where α ≤ 60°.

[0021] In the above technical solution, when α≤60°, the angle between the transition surface and the axis of the cylindrical battery cell is small, the transition surface is relatively smooth, which is more conducive to reducing the risk of the insulating film lifting.

[0022] As an optional technical solution in this application embodiment, the first region has a first surface that is away from the outer peripheral surface of the first anti-corrosion layer. Along the radial direction of the cylindrical battery cell, the distance between the first surface and the outer peripheral surface of the first anti-corrosion layer is H, which satisfies: 3μm≤H≤100μm.

[0023] In the above technical solution, when H ≥ 3 μm, the thickness of the first region is relatively large, which provides better protection, helps alleviate the rusting of the first substrate, and improves the lifespan of the cylindrical battery cell. When H ≤ 100 μm, the thickness of the first region is not excessive, which helps reduce space occupation and improves the energy density of the cylindrical battery cell. Therefore, when 3 μm ≤ H ≤ 100 μm, both the lifespan and energy density of the cylindrical battery cell can be balanced.

[0024] As an optional technical solution in this application embodiment, 5μm≤H≤20μm.

[0025] In the above technical solutions, when H ≥ 5 μm, the thickness of the first region is greater, providing better protection, mitigating rusting of the first substrate, and improving the lifespan of the cylindrical battery cell. When H ≤ 20 μm, the thickness of the first region is not excessive, reducing space occupation and improving the energy density of the cylindrical battery cell. Therefore, when 5 μm ≤ H ≤ 20 μm, a better balance between the lifespan and energy density of the cylindrical battery cell can be achieved.

[0026] As an optional technical solution in this application embodiment, the protective coating includes a first portion disposed on the outer peripheral surface of the first anti-corrosion layer along the axial direction of the cylindrical battery cell, and the size of the first portion is L, satisfying: 0.5mm≤L≤10mm.

[0027] In the above technical solution, when L ≥ 0.5 mm, the first part has a larger axial dimension along the cylindrical battery cell, resulting in a larger area of ​​the protective coating covering the outer periphery of the first anti-corrosion layer. This is beneficial for improving the protective effect of the protective coating, alleviating rusting of the first substrate, and extending the lifespan of the cylindrical battery cell. When L ≤ 10 mm, the first part's axial dimension along the cylindrical battery cell is not too large, ensuring that the area of ​​the protective coating covering the outer periphery of the first anti-corrosion layer is not too large, thus reducing the production cost of the cylindrical battery cell. Therefore, when 0.5 mm ≤ L ≤ 10 mm, it is beneficial for both extending the lifespan of the cylindrical battery cell and reducing its production cost.

[0028] As an optional technical solution in this application embodiment, 1mm≤L≤5mm.

[0029] In the above technical solution, when L≥1mm, the first part has a larger axial dimension along the cylindrical battery cell, resulting in a larger area of ​​the protective coating covering the outer periphery of the first anti-corrosion layer. This improves the protective effect of the coating, helps alleviate rusting of the first substrate, and extends the lifespan of the cylindrical battery cell. When L≤5mm, the first part's axial dimension along the cylindrical battery cell is not too large, preventing the protective coating from covering an excessively large area of ​​the outer periphery of the first anti-corrosion layer, thus reducing the production cost of the cylindrical battery cell. Therefore, when 1mm≤L≤5mm, it is beneficial to both improve the lifespan of the cylindrical battery cell and reduce its production cost.

[0030] As an optional technical solution in this application embodiment, the protective coating has a ring structure, and at least a portion of the protective coating is disposed around the outer peripheral surface of the first anti-corrosion layer.

[0031] In the above technical solution, at least a portion of the protective coating is provided around the outer peripheral surface of the first anti-corrosion layer, which can protect the sidewalls along the circumference of the cylindrical battery cell. This is beneficial to improving the protective effect of the protective coating, alleviating the rusting phenomenon of the first substrate, and improving the lifespan of the cylindrical battery cell.

[0032] As an optional technical solution in this application embodiment, along the axial direction of the cylindrical battery cell, the protective coating is at a distance from the end of the sidewall that is away from the end wall.

[0033] In the above technical solution, the area of ​​the first anti-corrosion layer near the end of the sidewall away from the end wall has a lower risk of cracking during processing. Furthermore, due to its distance from the end wall, the risk of spilled electrolyte seeping into the first substrate is lower. Therefore, the area of ​​the first substrate near the end of the sidewall away from the end wall has a lower risk of rusting. By maintaining a distance between the protective coating and the end of the sidewall away from the end wall along the axial direction of the cylindrical battery cell, it is beneficial to reduce the production cost of the cylindrical battery cell.

[0034] As an optional technical solution in this application embodiment, the protective coating includes a metallic material, the electrode potential of which is lower than that of steel.

[0035] In the above technical solution, by making the protective coating include metal material and making the electrode potential of the metal material lower than that of steel, the metal material can act as a sacrificial anode, which helps to alleviate the rusting phenomenon of the first substrate and improves the lifespan of the cylindrical battery cell.

[0036] As an optional technical solution in this application embodiment, the mass ratio of the metal material is greater than or equal to 10%.

[0037] In the above technical solution, by making the mass ratio of metal material greater than or equal to 10%, the mass of metal material is relatively large, which has sufficient sacrificial protection capability and is conducive to improving the protective effect of the protective coating.

[0038] As an optional technical solution in this application embodiment, the protective coating includes petroleum sulfonate.

[0039] In the above technical solution, the sulfonic acid groups in petroleum sulfonate molecules form chemical bonds with the metal surface (especially the first substrate exposed under the crack of the first anti-corrosion layer) to construct a nanoscale dense protective film, which can effectively block the penetration of corrosive factors, thereby achieving a good anti-rust effect.

[0040] Secondly, embodiments of this application also provide a battery device, which includes the aforementioned cylindrical battery cell.

[0041] 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

[0042] 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.

[0043] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0044] Figure 2 Exploded views of battery devices provided in some embodiments of this application;

[0045] Figure 3 This is a schematic diagram of the structure of a cylindrical battery cell provided in some embodiments of this application;

[0046] Figure 4 Exploded views of cylindrical battery cells provided in some embodiments of this application;

[0047] Figure 5 A top view schematic diagram of the housing provided for some embodiments of this application;

[0048] Figure 6 for Figure 5 A cross-sectional view at position AA in the middle;

[0049] Figure 7 for Figure 6 A magnified view of position B in the middle;

[0050] Figure 8 Partial cross-sectional view of the housing provided for other embodiments of this application;

[0051] Figure 9 Schematic diagrams of the structure of a cylindrical battery cell provided in some embodiments of this application;

[0052] Figure 10 Exploded views of a cylindrical battery cell provided for some embodiments of this application;

[0053] Figure 11 A top view schematic diagram of the housing provided for some embodiments of this application;

[0054] Figure 12 for Figure 11 A cross-sectional view at position CC;

[0055] Figure 13 for Figure 12 A magnified view of position D in the middle;

[0056] Figure 14 A partial cross-sectional view of the housing provided in some embodiments of this application.

[0057] Icons: 10-Box body; 11-First box body; 12-Second box body; 20-Cylindrical battery cell; 21-Outer shell; 211-Shell; 2111-Side wall; 21111-First substrate; 21112-First anti-corrosion layer; 21113-Outer peripheral surface of the first anti-corrosion layer; 21114-Recess; 2112-End wall; 21121-Lead-out hole; 21122-Second substrate; 21123-Second anti-corrosion layer; 21124-Outer surface of the second anti-corrosion layer; 2113-Corner wall; 21131-Third substrate; 21132-Third anti-corrosion layer; 21133-Outer surface of the third anti-corrosion layer; 21134-First end; 2113 5-Second end; 212-End cap; 22-Electrode assembly; 221-Main body; 222-Electrode tab; 2221-First electrode tab; 2222-Second electrode tab; 23-Electrode terminal; 231-Injection hole; 24-Current collector; 241-First current collector; 242-Second current collector; 25-Sealing pin; 26-Protective coating; 261-First part; 2611-First region; 26111-Third end; 26112-Fourth end; 26113-First surface; 2612-Second region; 26121-Transition surface; 262-Second part; 100-Battery device; 200-Controller; 300-Motor; 1000-Vehicle. Detailed Implementation

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] In this application, "multiple" means two or more (including two).

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.).

[0071] 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 0.05 At least one of O2 and its modified compounds.

[0072] 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.

[0073] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0074] 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.).

[0075] 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.

[0076] 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.

[0077] 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.

[0078] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0079] In some embodiments, the separator is a separator membrane. The separator membrane can be any known porous structure separator membrane with good chemical and mechanical stability.

[0080] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0081] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0082] 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 liquid, gel-like, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0083] 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.

[0084] 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.

[0085] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0086] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0087] As an example, polymer solid electrolytes can be polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0088] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0089] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0090] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0091] In some implementations, the electrode assembly is a stacked structure.

[0092] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0093] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0094] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0095] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0096] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0097] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] As an example, a battery module can be formed by bundling multiple cylindrical battery cells together with cable ties.

[0103] 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.

[0104] 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.

[0105] As an example, cylindrical battery cell assemblies can also be housed in a housing by directly fixing multiple cylindrical battery cells to the housing.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] In typical battery cells, the outer casing is usually made of aluminum. This casing has advantages such as low hardness and good plasticity, resulting in better formability. To meet strength requirements, the aluminum casing needs to be thicker. However, with a fixed battery cell volume, a thicker aluminum casing results in a lower volumetric energy density, thus affecting the battery cell's volumetric energy density. Therefore, a steel casing can be used. While meeting strength requirements, the outer casing can be made thinner, thereby increasing the battery cell's volumetric energy density.

[0113] In related technologies, the steel shell includes a housing and end caps. The housing includes an integrally formed end wall and side walls. The side walls surround the end wall, with one end connected to the end wall and the other end connected to the end cap. Generally, steel with a pre-coated anti-corrosion layer is stamped to form the housing. However, during processing, the anti-corrosion layer on the side wall near the end wall is subjected to significant tensile stress, making it prone to cracking. This exposes the steel substrate, making it susceptible to rust. Furthermore, because the end wall has injection holes or electrode terminals with injection holes, some electrolyte inevitably spills out during the injection of electrolyte into the cylindrical battery cell. This spilled electrolyte seeps into the steel substrate through cracks, accelerating corrosion and resulting in a shorter cycle life for the cylindrical battery cell.

[0114] Therefore, this application provides a cylindrical battery cell, which includes an electrode assembly, a housing, and a protective coating. The electrode assembly is housed within the housing. The housing includes an end wall and a side wall, with the side wall surrounding the end wall. The side wall includes a first substrate and a first anti-corrosion layer, with the first anti-corrosion layer disposed on the outer surface of the first substrate. The end wall includes a second substrate and a second anti-corrosion layer, with the second anti-corrosion layer disposed on the outer surface of the second substrate. The first and second substrates are integrally formed, as are the first and second anti-corrosion layers, and the materials of the first and second substrates include steel. The end wall is provided with a liquid injection hole, or the end wall is provided with an electrode terminal, with the electrode terminal having a liquid injection hole. The protective coating is at least partially disposed on the outer peripheral surface of the first anti-corrosion layer, and along the axial direction of the cylindrical battery cell, the protective coating extends at least to the end of the outer peripheral surface of the first anti-corrosion layer near the second anti-corrosion layer.

[0115] The outer casing can be manufactured using a stamping process, allowing the first and second substrates to be integrally formed, as well as the first and second anti-corrosion layers. By applying a protective coating to the outer circumferential surface of the first anti-corrosion layer, extending at least to the end of the outer circumferential surface of the first anti-corrosion layer along the axis of the cylindrical battery cell near the second anti-corrosion layer, the protective coating can cover cracks generated in the first anti-corrosion layer during processing. This helps reduce the risk of electrolyte spilling during electrolyte injection into the first substrate, alleviates rusting of the first substrate, and improves the lifespan of the cylindrical battery cell.

[0116] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells and battery devices. The electrical devices can be of various types, 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.

[0117] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] Please refer to Figure 2 , Figure 2 This 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 , Figure 3 This is a schematic diagram of the structure of a cylindrical battery cell 20 provided in some embodiments of this application. Figure 4 An exploded view of a cylindrical battery cell 20 provided in some embodiments of this application. Figure 5 This is a top view of the housing 21 provided for some embodiments of this application. Figure 6 for Figure 5 A cross-sectional view at position AA. Figure 7 for Figure 6Enlarged view of position B. This application provides a cylindrical battery cell 20, which includes an electrode assembly 22, a housing 21, and a protective coating 26. The electrode assembly 22 is housed within the housing 21. The housing 21 includes an end wall 2112 and a side wall 2111, with the side wall 2111 surrounding the end wall 2112. The side wall 2111 includes a first substrate 21111 and a first anti-corrosion layer 21112, the first anti-corrosion layer 21112 being disposed on the outer surface of the first substrate 21111. The end wall 2112 includes a second substrate 21122 and a second anti-corrosion layer 21123, the second anti-corrosion layer 21123 being disposed on the outer surface of the second substrate 21122. The first substrate 21111 and the second substrate 21122 are integrally formed, as are the first anti-corrosion layer 21112 and the second anti-corrosion layer 21123. The material of the first substrate 21111 and the second substrate 21122 includes steel. The end wall 2112 is provided with a liquid injection hole 231, or the end wall 2112 is provided with an electrode terminal 23, and the electrode terminal 23 is provided with a liquid injection hole 231. The protective coating 26 is at least partially disposed on the outer peripheral surface 21113 of the first anti-corrosion layer, and along the axial direction of the cylindrical battery cell 20, the protective coating 26 extends at least to the end of the outer peripheral surface 21113 of the first anti-corrosion layer near the second anti-corrosion layer 21123.

[0126] Cylindrical battery cell 20 refers to the smallest unit that makes up battery device 100.

[0127] The housing 21 includes a housing 211 and an end cap 212. The housing 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 housing 211 and closes the opening.

[0128] End cap 212 is a component that covers the opening of housing 211 to isolate the internal environment of cylindrical battery cell 20 from the external environment. End cap 212 can be connected to housing 211 by welding or roll sealing to close the opening of housing 211. The shape of end cap 212 can be adapted to the shape of housing 21; for example, if housing 211 is cylindrical, end cap 212 is a circular plate structure adapted to housing 211.

[0129] 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.

[0130] 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 or stacking positive and negative electrode sheets, and typically a separator 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.

[0131] The axial direction of the cylindrical battery cell 20 is the extension direction of the central axis of the cylindrical battery cell 20. Please refer to... Figure 3 and Figure 4 The axial direction of the cylindrical battery cell 20 is the X direction shown in the figure.

[0132] The housing 211 includes an end wall 2112 and a side wall 2111, which are integrally formed. The side wall 2111 surrounds the end wall 2112. Along the axial direction of the cylindrical battery cell 20, one end of the side wall 2111 is connected to the end wall 2112, and the other end of the side wall 2111 is connected to the end cap 212. In other words, along the axial direction of the cylindrical battery cell 20, the end wall 2112 and the end cap 212 are arranged opposite to each other, and the end wall 2112 and the end cap 212 are respectively connected to the two ends of the side wall 2111. During manufacturing, steel pre-coated with an anti-corrosion layer can be used for stamping to form the housing 211.

[0133] The first substrate 21111 is the base material of the sidewall 2111, and the first substrate 21111 can be made of steel, such as carbon steel. The first anti-corrosion layer 21112 is the surface layer of the sidewall 2111, and the thickness of the first anti-corrosion layer 21112 is less than the thickness of the first substrate 21111. The first anti-corrosion layer 21112 can be a plating layer disposed on the surface of the first substrate 21111. The material of the first anti-corrosion layer 21112 can include at least one of nickel, aluminum, zinc, etc.

[0134] As an example, in Figure 7 In this structure, the outer peripheral surface 21113 of the first anti-corrosion layer is the outer peripheral surface of the sidewall 2111, making the first anti-corrosion layer 21112 the surface layer of the sidewall 2111. The first anti-corrosion layer 21112 has better corrosion resistance than the first substrate 21111, giving the sidewall 2111 excellent rust prevention capabilities.

[0135] In some embodiments, the first anti-corrosion layer 21112 includes a nickel layer.

[0136] It is possible that a portion of the first anti-corrosion layer 21112 is a nickel layer, or the first anti-corrosion layer 21112 itself is a nickel layer.

[0137] The nickel layer has good corrosion resistance and high hardness. The first anti-corrosion layer 21112 includes a nickel layer, which improves the corrosion resistance and wear resistance of the sidewall 2111.

[0138] The second substrate 21122 is the base material of the end wall 2112, and the second substrate 21122 can be made of steel, such as carbon steel. The second anti-corrosion layer 21123 is the surface layer of the end wall 2112, and the thickness of the second anti-corrosion layer 21123 is less than the thickness of the second substrate 21122. The second anti-corrosion layer 21123 can be a plating layer disposed on the surface of the second substrate 21122. The material of the second anti-corrosion layer 21123 can include at least one of nickel, aluminum, zinc, etc.

[0139] As an example, in Figure 7 In this design, the outer surface 21124 of the second anti-corrosion layer is the outer surface of the end wall 2112, making the second anti-corrosion layer 21123 the surface layer of the end wall 2112. The second anti-corrosion layer 21123 has better corrosion resistance than the second substrate 21122, giving the end wall 2112 excellent rust prevention capabilities.

[0140] In some embodiments, the second anti-corrosion layer 21123 includes a nickel layer.

[0141] It is possible that part of the second anti-corrosion layer 21123 is a nickel layer, or the second anti-corrosion layer 21123 is itself a nickel layer.

[0142] The nickel layer has good corrosion resistance and high hardness. The second anti-corrosion layer 21123 includes the nickel layer, which improves the corrosion resistance and wear resistance of the end wall 2112.

[0143] The first substrate 21111 and the second substrate 21122 can be directly connected, or they can be indirectly connected. The first anti-corrosion layer 21112 and the second anti-corrosion layer 21123 can be directly connected, or they can be indirectly connected. Please refer to... Figure 6 and Figure 7 In the embodiment shown in the figure, the first substrate 21111 and the second substrate 21122 are directly connected, and the first anti-corrosion layer 21112 and the second anti-corrosion layer 21123 are directly connected.

[0144] When steel with a pre-coated anti-corrosion layer is used for stamping to form the shell 211, the first substrate 21111 and the second substrate 21122 are both part of the steel, making the first substrate 21111 and the second substrate 21122 an integral structure. The first anti-corrosion layer 21112 and the second anti-corrosion layer 21123 are both part of the pre-coated anti-corrosion layer, making the first anti-corrosion layer 21112 and the second anti-corrosion layer 21123 an integral structure.

[0145] The first substrate 21111 and the second substrate 21122 are made of steel. The materials of the first substrate 21111 and the second substrate 21122 can be carbon steel or stainless steel. Carbon steel includes low-carbon steel, medium-carbon steel, and high-carbon steel. For example, carbon steel can be Q195 carbon steel, SPCC carbon steel, etc. Stainless steel can be SUS430 stainless steel, SUS304 stainless steel, SUS316 stainless steel, or modified stainless steel, etc.

[0146] The cylindrical battery cell 20 includes an injection hole 231, which is a through hole for injecting electrolyte into the casing 21.

[0147] In some embodiments, the injection hole 231 is disposed on the end wall 2112, and the injection hole 231 penetrates the second substrate 21122 and the second anti-corrosion layer 21123 along the axial direction of the cylindrical battery cell 20.

[0148] The cylindrical battery cell 20 includes an electrode terminal 23 disposed on the housing 21. The electrode terminal 23 is used to electrically connect to the tab 222 of the electrode assembly 22 to input or output electrical energy of the cylindrical battery cell 20. The electrode terminal 23 and the tab 222 can be directly connected, for example, by welding the electrode terminal 23 to the tab 222. The electrode terminal 23 and the tab 222 can also be indirectly connected, for example, by connecting the electrode terminal 23 and the tab 222 through a current collector 24. The 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 the electrode assembly 22 (one of the positive tab and the negative tab) can be electrically connected to the electrode terminal 23, and the other tab 222 of the electrode assembly 22 (the other of the positive tab and the negative tab) can be electrically connected to the housing 21.

[0149] The outer casing 21 is provided with a lead-out hole 21121, and the electrode terminal 23 is mounted in the lead-out hole 21121. As an example, the liquid injection hole 231 and the lead-out hole 21121 can both be provided on the end wall 2112. The lead-out hole 21121 penetrates the second substrate 21122 and the second anti-corrosion layer 21123 along the axial direction of the cylindrical battery cell 20. That is, the lead-out hole 21121 is a through hole provided on the end wall 2112. In this case, the liquid injection hole 231 and the lead-out hole 21121 are spaced apart on the end wall 2112, and the liquid injection hole 231 and the lead-out hole 21121 are two different through holes.

[0150] As an example, the injection hole 231 can be provided on the end wall 2112, and the outlet hole 21121 can be provided on the end cap 212.

[0151] In other embodiments, electrode terminals 23 are disposed on end walls 2112, and liquid injection holes 231 are disposed on electrode terminals 23, with the liquid injection holes 231 penetrating the electrode terminals 23 along the axial direction of the cylindrical battery cell 20.

[0152] The cylindrical battery cell 20 also includes a sealing pin 25, which is used to seal the injection hole 231 after the cylindrical battery cell 20 is filled with electrolyte.

[0153] As an example, such as Figure 3 and Figure 4As shown, an electrode terminal 23 is provided on the end wall 2112, and an injection hole 231 is provided on the electrode terminal 23. Both ends of the electrode assembly 22 have tabs 222, which are respectively a first tab 2221 and a second tab 2222. 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. The cylindrical battery cell 20 also includes an insulating component, at least a portion of which is disposed between the first current collector 241 and the end wall 2112 to insulate and isolate the first current collector 241 and the end wall 2112.

[0154] The protective coating 26 may cover a portion or all of the outer peripheral surface 21113 of the first anti-corrosion layer. The protective coating 26 is at least partially disposed on the outer peripheral surface 21113 of the first anti-corrosion layer. The protective coating 26 serves to prevent media from the external environment from contacting the first substrate 21111 through cracks in the first anti-corrosion layer 21112, thereby achieving a rust-proof effect. Therefore, the protective coating 26 can also be referred to as a rust-proof layer. The protective coating 26 may be an insulating material, or it may include metallic materials.

[0155] The phrase "along the axial direction of the cylindrical battery cell 20, the protective coating 26 extends at least to the end of the outer peripheral surface 21113 of the first anti-corrosion layer near the second anti-corrosion layer 21123" can mean: one end of the protective coating 26 extends to the end of the outer peripheral surface 21113 of the first anti-corrosion layer near the second anti-corrosion layer 21123 along the axial direction of the cylindrical battery cell 20, and the other end of the protective coating 26 is at a distance from the end of the outer peripheral surface 21113 of the first anti-corrosion layer away from the second anti-corrosion layer 21123 along the axial direction of the cylindrical battery cell 20; or one end of the protective coating 26 extends to the end of the outer peripheral surface 21113 of the first anti-corrosion layer near the second anti-corrosion layer 21123 along the axial direction of the cylindrical battery cell 20, and the other end of the protective coating 26 extends to the first anti-corrosion layer... The outer peripheral surface 21113 extends away from the second anti-corrosion layer 21123 along the axial direction of the cylindrical battery cell 20 (that is, the two ends of the protective coating 26 extend to the two ends of the outer peripheral surface 21113 of the first anti-corrosion layer, respectively). It can be that the protective coating 26 extends to the end of the outer peripheral surface 21113 of the first anti-corrosion layer along the axial direction of the cylindrical battery cell 20 and closes to the second anti-corrosion layer 21123 and ends, or the protective coating 26 extends to the end of the outer peripheral surface 21113 of the first anti-corrosion layer along the axial direction of the cylindrical battery cell 20 and closes to the second anti-corrosion layer 21123 and continues to extend (that is, the protective coating 26 can extend beyond the end of the outer peripheral surface 21113 of the first anti-corrosion layer along the axial direction of the cylindrical battery cell 20 and closes to the second anti-corrosion layer 21123).

[0156] Please refer to Figure 6 and Figure 7 In the embodiment shown in the figure, one end of the protective coating 26 extends to the outer peripheral surface 21113 of the first anti-corrosion layer along the axial direction of the cylindrical battery cell 20 and is close to the end of the second anti-corrosion layer 21123. The end face of the protective coating 26 at the aforementioned end is flush with the outer surface 21124 of the second anti-corrosion layer. The other end of the protective coating 26 is at a distance from the end of the outer peripheral surface 21113 of the first anti-corrosion layer along the axial direction of the cylindrical battery cell 20 and away from the second anti-corrosion layer 21123.

[0157] The outer casing 21 can be manufactured by stamping, so that the first substrate 21111 and the second substrate 21122 are integrally formed, as are the first anti-corrosion layer 21112 and the second anti-corrosion layer 21123. By providing a protective coating 26 on the outer peripheral surface 21113 of the first anti-corrosion layer, and extending the protective coating 26 at least to the end of the outer peripheral surface 21113 of the first anti-corrosion layer near the second anti-corrosion layer along the axis of the cylindrical battery cell 20, the protective coating 26 can cover the cracks generated in the first anti-corrosion layer 21112 during processing. This helps reduce the risk of electrolyte spilled during injection seeping into the first substrate 21111, helps alleviate the rusting phenomenon of the first substrate 21111, and helps improve the lifespan of the cylindrical battery cell 20.

[0158] Please refer to Figure 8 , Figure 8 This is a partial cross-sectional view of the housing 21 provided for other embodiments of this application. In other embodiments, the outer peripheral surface 21113 of the first anti-corrosion layer is provided with a recess 21114, and a portion of the protective coating 26 is accommodated within the recess 21114.

[0159] The recess 21114 is a groove structure or a recessed structure. The recess 21114 provided on the outer peripheral surface 21113 of the first anti-corrosion layer is recessed from the outer peripheral surface 21113 of the first anti-corrosion layer into the first anti-corrosion layer 21112.

[0160] The portion of the protective coating 26 accommodated within the recess 21114 may or may not completely fill the recess 21114. Alternatively, the portion of the protective coating 26 accommodated within the recess 21114 may be connected to the wall of the recess 21114; or the portion may not be connected to the wall of the recess 21114, for example, the portion of the protective coating 26 accommodated within the recess 21114 may be inserted into the recess 21114, such that the portion of the protective coating 26 accommodated within the recess 21114 only maintains contact with the wall of the recess 21114.

[0161] In some embodiments, the recess 21114 is a crack generated by tensile stress on the first anti-corrosion layer 21112 during processing. In other embodiments, the recess 21114 is a groove artificially processed. For example, the recess 21114 provided on the outer peripheral surface 21113 of the first anti-corrosion layer can be formed on the outer peripheral surface 21113 of the first anti-corrosion layer by laser cleaning, stamping, milling, etc. The cross-section of the recess 21114 can be rectangular, V-shaped, semi-circular, etc., and the cross-section of the recess 21114 is perpendicular to the extension direction of the recess 21114. Figure 8 (Not shown in the image). The extension trajectory of the recess 21114 can be a straight line, an arc, a circle, a planar spiral, a helix, etc.

[0162] In some embodiments, a plurality of recesses 21114 are provided on the outer peripheral surface 21113 of the first anti-corrosion layer, and the plurality of recesses 21114 are spaced apart. The number of recesses 21114 can be two, three, four, five, six or more.

[0163] By providing a recess 21114 on the outer peripheral surface 21113 of the first anti-corrosion layer and accommodating a portion of the protective coating 26 within the recess 21114, the recess 21114 can restrict the protective coating 26 to a certain extent, which helps to improve the firmness of the protective coating 26 on the sidewall 2111, achieve long-term protection of the sidewall 2111, reduce the risk of the protective coating 26 falling off the outer peripheral surface 21113 of the first anti-corrosion layer in a short period of time and causing protective failure, help to alleviate the rusting phenomenon of the first substrate 21111, and help to improve the life of the cylindrical battery cell 20.

[0164] Please refer to Figure 8 In some embodiments, the portion of the protective coating 26 contained within the recess 21114 is connected to the wall of the recess 21114.

[0165] The portion of the protective coating 26 contained within the recess 21114 is connected to the wall surface of the recess 21114, resulting in a certain degree of adhesion between the portion of the protective coating 26 contained within the recess 21114 and the wall surface of the recess 21114. The portion of the protective coating 26 contained within the recess 21114 may cover a portion of the wall surface of the recess 21114, or it may cover the entire wall surface of the recess 21114. It is understood that if the portion of the protective coating 26 contained within the recess 21114 completely fills the recess 21114, then the portion of the protective coating 26 contained within the recess 21114 covers the entire wall surface of the recess 21114.

[0166] The wall of the recess 21114 defines the internal space of the recess 21114. Taking the cross-section of the recess 21114 as rectangular as an example, the wall of the recess 21114 may include a side surface and a bottom surface. The bottom surface is disposed opposite to the open end of the recess 21114. The portion of the protective coating 26 accommodated in the recess 21114 may be connected to the side surface and / or the bottom surface of the recess 21114.

[0167] The portion of the protective coating 26 contained within the recess 21114 is connected to the wall of the recess 21114, which helps to increase the contact area between the protective coating 26 and the housing 211, thereby increasing the adhesion of the protective coating 26 to the housing 211 and further improving the firmness of the protective coating 26 on the housing 211.

[0168] Please refer to Figure 9 , Figure 10 , Figure 11 , Figure 12 and Figure 13 , Figure 9 This is a schematic diagram of the structure of a cylindrical battery cell 20 provided in some embodiments of this application. Figure 10 An exploded view of a cylindrical battery cell 20 provided in some embodiments of this application. Figure 11 A top view of the housing 21 provided for some embodiments of this application. Figure 12 for Figure 11 A cross-sectional view at position CC. Figure 13 for Figure 12 Enlarged view of position D. In some embodiments, the outer casing 21 includes a corner wall 2113, which includes a third substrate 21131 and a third anti-corrosion layer 21132, the third anti-corrosion layer 21132 being disposed on the outer surface of the third substrate 21131. The material of the third substrate 21131 includes steel, and the third substrate 21131 connects to the first substrate 21111 and the second substrate 21122, the first substrate 21111, the second substrate 21122 and the third substrate 21131 being integrally formed. The third anti-corrosion layer 21132 connects to the first anti-corrosion layer 21112 and the second anti-corrosion layer 21123, the first anti-corrosion layer 21112, the second anti-corrosion layer 21123 and the third anti-corrosion layer 21132 being integrally formed. The outer surface 21133 of the third anti-corrosion layer connects the outer surface 21124 of the second anti-corrosion layer and the outer peripheral surface 21113 of the first anti-corrosion layer, and the protective coating 26 covers at least a portion of the outer surface 21133 of the third anti-corrosion layer.

[0169] The corner wall 2113 is the wall connecting the side wall 2111 and the end wall 2112 of the outer casing 21. The corner wall 2113 surrounds the end wall 2112, and the end wall 2112 smoothly transitions to the side wall 2111 through the corner wall 2113, thereby reducing the stress at the connection point between the end wall 2112 and the side wall 2111. Please refer to... Figure 13Within the cross-section passing through the axis of the cylindrical battery cell 20, the cross-sectional shape of the corner wall 2113 extends along a circular arc trajectory. The corner wall 2113 can be understood as a rounded transition wall connecting the side wall 2111 and the end wall 2112.

[0170] To distinguish between sidewall 2111, corner wall 2113, and end wall 2112, Figure 13 The boundary positions of side wall 2111, corner wall 2113, and end wall 2112 are shown by dashed lines. It should be noted that the dashed lines are only used to mark the boundary positions of side wall 2111, corner wall 2113, and end wall 2112, and do not represent any other meaning.

[0171] The third substrate 21131 is the base material of the corner wall 2113, and can be made of steel, such as carbon steel. The third anti-corrosion layer 21132 is the surface layer of the corner wall 2113, and the thickness of the third anti-corrosion layer 21132 is less than the thickness of the third substrate 21131. The third anti-corrosion layer 21132 can be a plating layer applied to the surface of the third substrate 21131. The material of the third anti-corrosion layer 21132 can include at least one of nickel, aluminum, zinc, etc.

[0172] As an example, in Figure 13 In this design, the outer surface 21133 of the third anti-corrosion layer is the outer surface of the corner wall 2113, making the third anti-corrosion layer 21132 the surface layer of the corner wall 2113. The third anti-corrosion layer 21132 has better corrosion resistance than the third substrate 21131, giving the corner wall 2113 excellent rust prevention capabilities.

[0173] In some embodiments, the third anti-corrosion layer 21132 includes a nickel layer.

[0174] It can be that part of the third anti-corrosion layer 21132 is a nickel layer, or the third anti-corrosion layer 21132 is a nickel layer.

[0175] The nickel layer has good corrosion resistance and high hardness. The third anti-corrosion layer 21132 includes a nickel layer, which improves the corrosion resistance and wear resistance of the corner wall 2113.

[0176] When steel with a pre-coated anti-corrosion layer is used for stamping to form the shell 211, the first substrate 21111, the second substrate 21122, and the third substrate 21131 are all part of the steel, making the first substrate 21111, the second substrate 21122, and the third substrate 21131 an integral structure. The first anti-corrosion layer 21112, the second anti-corrosion layer 21123, and the third anti-corrosion layer 21132 are all part of the pre-coated anti-corrosion layer, making the first anti-corrosion layer 21112, the second anti-corrosion layer 21123, and the third anti-corrosion layer 21132 an integral structure.

[0177] The material of the third substrate 21131 includes steel, which can be carbon steel or stainless steel. Carbon steel includes low-carbon steel, medium-carbon steel, and high-carbon steel. For example, carbon steel can be Q195 carbon steel, SPCC carbon steel, etc. Stainless steel can be SUS430 stainless steel, SUS304 stainless steel, SUS316 stainless steel, or modified stainless steel, etc.

[0178] The outer peripheral surface 21113 of the first anti-corrosion layer smoothly transitions to the outer surface 21124 of the second anti-corrosion layer through the outer surface 21133 of the third anti-corrosion layer, and the protective coating 26 covers part or all of the outer surface 21133 of the third anti-corrosion layer.

[0179] In some embodiments, the outer surface 21133 of the third anti-corrosion layer is provided with a recess 21114, and a portion of the protective coating 26 is accommodated within the recess 21114 to improve the adhesion of the protective coating 26 to the corner wall 2113. In some embodiments, the recess 21114 on the outer surface 21133 of the third anti-corrosion layer is a crack generated by tensile stress on the third anti-corrosion layer 21132 during processing. In other embodiments, the recess 21114 on the outer surface 21133 of the third anti-corrosion layer is a groove artificially processed. For example, the recess 21114 on the outer surface 21133 of the third anti-corrosion layer can be formed on the outer surface 21133 of the third anti-corrosion layer by laser cleaning, stamping, milling, or other methods.

[0180] In some embodiments, a plurality of recesses 21114 are provided on the outer peripheral surface of the third anti-corrosion layer 21132, and the plurality of recesses 21114 are spaced apart. The number of recesses 21114 can be two, three, four, five, six or more.

[0181] By providing a corner wall 2113 that connects the end wall 2112 and the side wall 2111, the risk of stress concentration at the connection point between the end wall 2112 and the side wall 2111 can be reduced. By covering at least a portion of the outer surface 21133 of the third anti-corrosion layer with the protective coating 26, the protective coating 26 can cover cracks generated in the third anti-corrosion layer 21132 during processing. This helps reduce the risk of electrolyte spilled during injection seeping into the third substrate 21131, alleviates rusting of the third substrate 21131, and improves the lifespan of the cylindrical battery cell 20.

[0182] Please refer to Figure 9 , Figure 10 , Figure 11 , Figure 12 and Figure 13In some embodiments, the outer surface 21133 of the third anti-corrosion layer includes a first end 21134 and a second end 21135. The first end 21134 is connected to the outer peripheral surface 21113 of the first anti-corrosion layer, and the second end 21135 is connected to the outer surface 21124 of the second anti-corrosion layer. The protective coating 26 includes a first portion 261 disposed on the outer peripheral surface 21113 of the first anti-corrosion layer and a second portion 262 disposed on the outer surface 21133 of the third anti-corrosion layer, with the first portion 261 and the second portion 262 connected. Along the direction from the first end 21134 to the second end 21135 of the outer surface 21133 of the third anti-corrosion layer, the distance between the outer surface of the second portion 262 and the outer surface 21133 of the third anti-corrosion layer gradually decreases.

[0183] The outer surface 21133 of the third anti-corrosion layer includes a first end 21134 and a second end 21135 disposed opposite to each other along its extending direction. The first end 21134 is the end of the outer surface 21133 of the third anti-corrosion layer that is connected to the outer peripheral surface 21113 of the first anti-corrosion layer. The second end 21135 is the end of the outer surface 21133 of the third anti-corrosion layer that is connected to the outer surface 21124 of the second anti-corrosion layer.

[0184] The first part 261 is the portion of the protective coating 26 disposed on the outer peripheral surface 21113 of the first anti-corrosion layer, and the second part 262 is the portion of the protective coating 26 disposed on the outer surface 21133 of the third anti-corrosion layer. The first part 261 and the second part 262 are connected.

[0185] "The distance between the outer surface of the second part 262 and the outer surface of the third anti-corrosion layer gradually decreases along the direction from the first end 21134 to the second end 21135 of the outer surface of the third anti-corrosion layer" means that the distance between the outer surface of the second part 262 and the outer surface of the third anti-corrosion layer gradually decreases along the direction from the first end 21134 to the second end 21135 of the outer surface of the third anti-corrosion layer, which also means that the thickness of the second part 262 gradually decreases from the first end 21134 to the second end 21135. It should be noted that in embodiments where a recess 21114 is provided on the outer surface of the third anti-corrosion layer and a portion of the protective coating 26 is accommodated within the recess 21114, when measuring the thickness of the second part 262, the distance between the outer surface of the second part 262 and the outer peripheral surface of the third anti-corrosion layer 21132 is directly measured, without considering the portion of the protective coating 26 accommodated within the recess 21114. The direction of the outer surface 21133 of the third anti-corrosion layer from the first end 21134 to the second end 21135 is as follows: In the extending direction of the outer surface 21133 of the third anti-corrosion layer, the direction from the first end 21134 to the second end 21135 is an arc. Please refer to... Figure 13The outer surface 21133 of the third anti-corrosion layer extends from the first end 21134 to the second end 21135 in the direction shown in the figure (N direction). During measurement, the casing 211 of the cylindrical battery cell 20 can be dissected for measurement, or it can be measured using a CT scan.

[0186] By gradually reducing the thickness of the second part 262 along the outer surface 21133 of the third anti-corrosion layer from the first end 21134 to the second end 21135, it is beneficial to reduce the risk of stress concentration in the second part 262 and the risk of peeling or cracking of the second part 262 in the short term, thus achieving long-term protection of the corner wall 2113.

[0187] Please refer to Figure 9 , Figure 10 , Figure 11 , Figure 12 and Figure 13 In some embodiments, the protective coating 26 completely covers the outer surface 21133 of the third anti-corrosion layer.

[0188] By ensuring that the protective coating 26 completely covers the outer surface 21133 of the third anti-corrosion layer, the protective effect on the third substrate 21131 is improved, the rusting phenomenon of the third substrate 21131 is further alleviated, and the lifespan of the cylindrical battery cell 20 is improved.

[0189] Please refer to Figure 9 , Figure 10 , Figure 11 , Figure 12 and Figure 13 In some embodiments, in the axial direction of the cylindrical battery cell 20, along the direction from the second substrate 21122 to the second anti-corrosion layer 21123, the protective coating 26 does not extend beyond the outer surface 21124 of the second anti-corrosion layer.

[0190] By ensuring that the protective coating 26 does not extend beyond the outer surface 21124 of the second anti-corrosion layer along the direction from the second substrate 21122 to the second anti-corrosion layer 21123, it is beneficial to reduce the risk of interference between the protective coating 26 and other components, and to reduce the risk of damage to the protective coating 26. On the other hand, it is beneficial to reduce space occupation and to improve the energy density of the cylindrical battery cell 20.

[0191] Please refer to Figure 14 , Figure 14This is a partial cross-sectional view of the housing 21 provided for some embodiments of this application. In some embodiments, the protective coating 26 includes a first portion 261 disposed on the outer peripheral surface 21113 of the first anti-corrosion layer. The first portion 261 includes a first region 2611 and a second region 2612. Along the axial direction of the cylindrical battery cell 20, the first region 2611 has a third end 26111 and a fourth end 26112 opposite to each other. The third end 26111 is connected to the second region 2612, and the fourth end 26112 extends to one end of the outer peripheral surface 21113 of the first anti-corrosion layer near the second anti-corrosion layer 21123. Along the direction from the fourth end 26112 to the third end 26111, the distance between the outer surface of the second region 2612 and the outer peripheral surface 21113 of the first anti-corrosion layer gradually decreases.

[0192] The first region 2611 is the portion of the first part 261 with a relatively uniform thickness. That is, the distance between the outer surface of the first region 2611 and the outer peripheral surface 21113 of the first anti-corrosion layer is approximately the same at various locations within the first region 2611 (the difference between the maximum and minimum distance between the outer surface of the first region 2611 and the outer peripheral surface 21113 of the first anti-corrosion layer does not exceed 10 μm). It should be noted that in embodiments where a recess 21114 is provided on the outer surface of the first anti-corrosion layer 21112, and a portion of the protective coating 26 is accommodated within the recess 21114, when measuring the thickness of the first region 2611, the distance between the outer surface of the first region 2611 and the outer peripheral surface 21113 of the first anti-corrosion layer can be measured directly, without considering the portion of the protective coating 26 accommodated within the recess 21114. During measurement, the casing 211 of the cylindrical battery cell 20 can be dissected for measurement, or it can be measured using a CT scan.

[0193] The third end 26111 and the fourth end 26112 are the two ends of the first region 2611 along the axial direction of the cylindrical battery cell 20, respectively. The third end 26111 is connected to the second region 2612, and the fourth end 26112 extends to the outer peripheral surface 21113 of the first anti-corrosion layer near the end of the second anti-corrosion layer 21123.

[0194] "The distance between the outer surface of the second region 2612 and the outer peripheral surface 21113 of the first anti-corrosion layer gradually decreases along the direction from the fourth end 26112 to the third end 26111." In other words, the thickness of the second region 2612 gradually decreases along the direction from the fourth end 26112 to the third end 26111. It should be noted that in embodiments where a recess 21114 is provided on the outer surface of the first anti-corrosion layer 21112, and a portion of the protective coating 26 is accommodated within the recess 21114, when measuring the thickness of the second region 2612, the distance between the outer surface of the second region 2612 and the outer peripheral surface 21113 of the first anti-corrosion layer is directly measured, without considering the portion of the protective coating 26 accommodated within the recess 21114. During measurement, the casing 211 of the cylindrical battery cell 20 can be cut open for measurement, or it can be measured by CT scan.

[0195] By gradually decreasing the thickness of the second region 2612 along the direction from the fourth end 26112 to the third end 26111, on the one hand, it helps to reduce the risk of stress concentration in the second region 2612 and the risk of peeling or cracking in the short term, thus achieving long-term protection for the sidewall 2111. On the other hand, it allows the insulating film covering the outside of the sidewall 2111 to gradually transition from the outer peripheral surface 21113 of the first anti-corrosion layer through the second region 2612 to the first region 2611, which helps to reduce the risk of the insulating film lifting.

[0196] Please refer to Figure 14 In some embodiments, the first region 2611 has a first surface 26113 facing away from the outer peripheral surface 21113 of the first anti-corrosion layer, and the second region 2612 has a transition surface 26121 that connects the first surface 26113 and the outer peripheral surface 21113 of the first anti-corrosion layer. The transition surface 26121 is a slope.

[0197] The first surface 26113 is the surface of the first region 2611 that faces away from the outer peripheral surface 21113 of the first anti-corrosion layer. The transition surface 26121 is the outer surface of the second region 2612. The transition surface 26121 connects the first surface 26113 and the outer peripheral surface 21113 of the first anti-corrosion layer. That is, the first surface 26113 transitions to the outer peripheral surface 21113 of the first anti-corrosion layer through the transition surface 26121.

[0198] The insulating film covering the outside of the sidewall 2111 can gradually transition from the outer peripheral surface 21113 of the first anti-corrosion layer to the first surface 26113 through the transition surface 26121. When the transition surface 26121 is a slope, it is more conducive to reducing the risk of the insulating film lifting.

[0199] Please refer to Figure 14 In some embodiments, the angle between the transition surface 26121 and the axis of the cylindrical battery cell 20 is α, where α ≤ 60°.

[0200] α represents the angle between the transition surface 26121 and the axis of the cylindrical battery cell 20. α can be 60°, 55°, 50°, 45°, 40°, 35°, 30°, 25°, 20°, etc.

[0201] When α≤60°, the angle between the transition surface 26121 and the axis of the cylindrical battery cell 20 is small, and the transition surface 26121 is relatively smooth, which is more conducive to reducing the risk of the insulating film lifting.

[0202] Please refer to Figure 14 In some embodiments, the first region 2611 has a first surface 26113 that is opposite to the outer peripheral surface 21113 of the first anti-corrosion layer. Along the radial direction of the cylindrical battery cell 20, the distance between the first surface 26113 and the outer peripheral surface 21113 of the first anti-corrosion layer is H, which satisfies: 3μm≤H≤100μm.

[0203] The radial direction of the cylindrical battery cell 20 is the direction in which the radius or diameter of the cylindrical battery cell 20 extends. Please refer to... Figure 14 The radial direction of the cylindrical battery cell 20 is the Y direction shown in the figure.

[0204] H represents the distance between the first surface 26113 along the radial direction of the cylindrical battery cell 20 and the outer peripheral surface 21113 of the first anti-corrosion layer. During measurement, the casing 211 of the cylindrical battery cell 20 can be cut open for measurement, or it can be measured by CT scan.

[0205] H can be: 3μm, 5μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, etc.

[0206] When H ≥ 3 μm, the thickness of the first region 2611 is relatively large, providing better protection and mitigating the rusting of the first substrate 21111, thus improving the lifespan of the cylindrical battery cell 20. When H ≤ 100 μm, the thickness of the first region 2611 is not excessive, reducing space occupation and improving the energy density of the cylindrical battery cell 20. Therefore, when 3 μm ≤ H ≤ 100 μm, both the lifespan and energy density of the cylindrical battery cell 20 can be balanced.

[0207] Optionally, 5μm≤H≤20μm.

[0208] H can be: 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, etc.

[0209] When H ≥ 5 μm, the thickness of the first region 2611 is greater, providing better protection and mitigating the rusting of the first substrate 21111, thus improving the lifespan of the cylindrical battery cell 20. When H ≤ 20 μm, the thickness of the first region 2611 is not excessive, reducing space occupation and improving the energy density of the cylindrical battery cell 20. Therefore, when 5 μm ≤ H ≤ 20 μm, a better balance between the lifespan and energy density of the cylindrical battery cell 20 can be achieved.

[0210] Please refer to Figure 14 In some embodiments, the protective coating 26 includes a first portion 261 disposed on the outer peripheral surface 21113 of the first anti-corrosion layer along the axial direction of the cylindrical battery cell 20. The size of the first portion 261 is L, which satisfies: 0.5mm≤L≤10mm.

[0211] L represents the length of the first part 261 along the axial direction of the cylindrical battery cell 20. It can be measured multiple times and the average value is taken as L.

[0212] L can be 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc.

[0213] When L ≥ 0.5 mm, the first portion 261 has a larger axial dimension along the cylindrical battery cell 20, resulting in a larger area covered by the protective coating 26 on the outer peripheral surface 21113 of the first anti-corrosion layer. This improves the protective effect of the protective coating 26, helps alleviate rusting of the first substrate 21111, and extends the lifespan of the cylindrical battery cell 20. When L ≤ 10 mm, the first portion 261's axial dimension along the cylindrical battery cell 20 is not too large, preventing the protective coating 26 from covering an excessively large area on the outer peripheral surface 21113 of the first anti-corrosion layer, thus reducing the production cost of the cylindrical battery cell 20. Therefore, when 0.5 mm ≤ L ≤ 10 mm, it is beneficial to both extend the lifespan of the cylindrical battery cell 20 and reduce its production cost.

[0214] Optionally, 1mm ≤ L ≤ 5mm.

[0215] L can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, etc.

[0216] When L ≥ 1 mm, the first portion 261 has a larger axial dimension along the cylindrical battery cell 20, resulting in a larger area covered by the protective coating 26 on the outer peripheral surface 21113 of the first anti-corrosion layer. This improves the protective effect of the protective coating 26, helps alleviate rusting of the first substrate 21111, and extends the lifespan of the cylindrical battery cell 20. When L ≤ 5 mm, the first portion 261's axial dimension along the cylindrical battery cell 20 is not too large, ensuring that the protective coating 26 does not cover an excessively large area on the outer peripheral surface 21113 of the first anti-corrosion layer, thus reducing the production cost of the cylindrical battery cell 20. Therefore, when 1 mm ≤ L ≤ 5 mm, it is beneficial to both improve the lifespan of the cylindrical battery cell 20 and reduce its production cost.

[0217] Please refer to Figure 9 , Figure 10 , Figure 11 , Figure 12 and Figure 13 In some embodiments, the protective coating 26 has an annular structure, and at least a portion of the protective coating 26 is disposed around the outer peripheral surface 21113 of the first anti-corrosion layer.

[0218] The protective coating 26 has a circular structure and can partially or completely surround the outer peripheral surface 21113 of the first anti-corrosion layer. For example, in an embodiment where the protective coating 26 is only disposed on the outer peripheral surface 21113 of the first anti-corrosion layer, the protective coating 26 completely surrounds the outer peripheral surface 21113 of the first anti-corrosion layer. In an embodiment where the first portion 261 of the protective coating 26 is disposed on the outer peripheral surface 21113 of the first anti-corrosion layer and the second portion 262 of the protective coating 26 is disposed on the outer surface 21133 of the third anti-corrosion layer, the first portion 261 surrounds the outer peripheral surface 21113 of the first anti-corrosion layer.

[0219] The circumferential direction of the cylindrical battery cell 20 is also the circumferential direction of the cylindrical battery cell 20. Please refer to [reference needed]. Figure 11 The circumferential direction of the cylindrical battery cell 20 is the Z direction shown in the figure.

[0220] The protective coating 26 is provided at least partially around the outer peripheral surface 21113 of the first anti-corrosion layer, which can protect the sidewall 2111 along the circumference of the cylindrical battery cell 20. This is beneficial to improving the protective effect of the protective coating 26, alleviating the rusting phenomenon of the first substrate 21111, and improving the life of the cylindrical battery cell 20.

[0221] Please refer to Figure 9 , Figure 10 , Figure 11 , Figure 12 and Figure 13In some embodiments, along the axial direction of the cylindrical battery cell 20, the protective coating 26 is at a distance from one end of the sidewall 2111 that is away from the endwall 2112.

[0222] "Along the axial direction of the cylindrical battery cell 20, there is a distance between the protective coating 26 and one end of the sidewall 2111 that is away from the end wall 2112." In other words, the protective coating 26 is at a distance from one end of the sidewall 2111 that is away from the end wall 2112 along the axial direction of the cylindrical battery cell 20. That is to say, the protective coating 26 does not extend to the end of the sidewall 2111 that is away from the end wall 2112.

[0223] The area of ​​the first anti-corrosion layer 21112 near the end of the sidewall 2111 opposite to the end wall 2112 has a lower risk of cracking during processing. Furthermore, due to its distance from the end wall 2112, the risk of spilled electrolyte seeping into the first substrate 21111 is lower. Therefore, the area of ​​the first substrate 21111 near the end of the sidewall 2111 opposite to the end wall 2112 has a lower risk of rusting. By maintaining a distance between the protective coating 26 and the end of the sidewall 2111 opposite to the end wall 2112 along the axial direction of the cylindrical battery cell 20, it is beneficial to reduce the production cost of the cylindrical battery cell 20.

[0224] In some embodiments, the protective coating 26 comprises a metallic material, the electrode potential of which is lower than that of steel.

[0225] When a metal comes into contact with its ionic solution, an electrical double layer forms at the metal / solution interface, generating a potential difference, i.e., electrode potential (unit: volts, V). The lower the potential (the more negative), the easier it is for the metal to lose electrons (oxidation reaction, such as corrosion); the higher the potential (the more positive), the easier it is for the metal to gain electrons (reduction reaction, such as deposition).

[0226] Metallic materials can be zinc, magnesium, aluminum, manganese, etc.

[0227] In embodiments where the protective coating 26 comprises a metallic material, the protective coating 26 may be a coating that can be observed with the naked eye or by scanning electron microscopy.

[0228] By including a metallic material in the protective coating 26 and making the electrode potential of the metallic material lower than that of the steel, the metallic material can act as a sacrificial anode, which helps to alleviate the rusting phenomenon of the first substrate 21111 and improves the lifespan of the cylindrical battery cell 20.

[0229] In some embodiments, the mass percentage of the metallic material is greater than or equal to 10%.

[0230] The mass percentage of metallic materials can be 10%, 12%, 15%, 20%, 25%, 30%, 35%, etc.

[0231] By making the mass ratio of the metal material greater than or equal to 10%, the mass of the metal material is larger, which provides sufficient sacrificial protection and helps to improve the protective effect of the protective coating 26.

[0232] In other embodiments, the protective coating 26 comprises petroleum sulfonate.

[0233] Petroleum sulfonates can be calcium petroleum sulfonate, sodium petroleum sulfonate, barium petroleum sulfonate, etc.

[0234] For embodiments where the protective coating 26 comprises petroleum sulfonate, this can be observed by elemental scanning.

[0235] The sulfonic acid groups in petroleum sulfonate molecules form chemical bonds with the metal surface (especially the first substrate 21111 exposed under the crack of the first anti-corrosion layer 21112) to build a nanoscale dense protective film, which can effectively block the penetration of corrosive agents, thereby achieving a good anti-rust effect.

[0236] This application embodiment also provides a battery device 100, which includes the above-described cylindrical battery cell 20.

[0237] 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.

[0238] According to some embodiments of this application, please refer to Figures 3-14 .

[0239] This application provides a cylindrical battery cell 20, which includes an electrode assembly 22, a housing 21, and a protective coating 26. The electrode assembly 22 is housed within the housing 21. The housing 21 includes an end wall 2112 and a side wall 2111, with the side wall 2111 surrounding the end wall 2112. The side wall 2111 includes a first substrate 21111 and a first anti-corrosion layer 21112, with the first anti-corrosion layer 21112 disposed on the outer surface of the first substrate 21111. The end wall 2112 includes a second substrate 21122 and a second anti-corrosion layer 21123, with the second anti-corrosion layer 21123 disposed on the outer surface of the second substrate 21122. The first substrate 21111 and the second substrate 21122 are integrally formed, as are the first anti-corrosion layer 21112 and the second anti-corrosion layer 21123. The first substrate 21111 and the second substrate 21122 are made of steel. The end wall 2112 is provided with a liquid injection hole 231, or the end wall 2112 is provided with an electrode terminal 23, and the electrode terminal 23 is provided with a liquid injection hole 231. A protective coating 26 is at least partially disposed on the outer peripheral surface 21113 of the first anti-corrosion layer, and along the axial direction of the cylindrical battery cell 20, the protective coating 26 extends at least to the end of the outer peripheral surface 21113 of the first anti-corrosion layer near the second anti-corrosion layer 21123. The outer casing 21 can be manufactured by stamping, so that the first substrate 21111 and the second substrate 21122 are integrally formed, and the first anti-corrosion layer 21112 and the second anti-corrosion layer 21123 are integrally formed. By providing a protective coating 26 on the outer peripheral surface 21113 of the first anti-corrosion layer, and extending the protective coating 26 at least to the end of the outer peripheral surface 21113 of the first anti-corrosion layer near the second anti-corrosion layer 21123 along the axis of the cylindrical battery cell 20, the protective coating 26 can cover the cracks generated in the first anti-corrosion layer 21112 during processing. This helps reduce the risk of electrolyte spilled during injection entering the first substrate 21111, helps alleviate the rusting phenomenon of the first substrate 21111, and helps improve the lifespan of the cylindrical battery cell 20.

[0240] A recess 21114 is provided on the outer peripheral surface 21113 of the first anti-corrosion layer, and a portion of the protective coating 26 is accommodated within the recess 21114. By providing the recess 21114 on the outer peripheral surface 21113 of the first anti-corrosion layer and accommodating a portion of the protective coating 26 within the recess 21114, the recess 21114 can restrict the protective coating 26 to a certain extent, which helps to improve the firmness of the protective coating 26 on the sidewall 2111, achieve long-term protection of the sidewall 2111, reduce the risk of the protective coating 26 falling off the outer peripheral surface 21113 of the first anti-corrosion layer in a short period of time and causing protective failure, help to alleviate the rusting phenomenon of the first substrate 21111, and help to improve the life of the cylindrical battery cell 20.

[0241] The outer casing 21 includes a corner wall 2113, which includes a third substrate 21131 and a third anti-corrosion layer 21132. The third anti-corrosion layer 21132 is disposed on the outer surface of the third substrate 21131. The material of the third substrate 21131 includes steel. The third substrate 21131 connects the first substrate 21111 and the second substrate 21122, which are integrally formed. The third anti-corrosion layer 21132 connects the first anti-corrosion layer 21112 and the second anti-corrosion layer 21123, which are integrally formed. The outer surface 21133 of the third anti-corrosion layer connects the outer surface 21124 of the second anti-corrosion layer and the outer peripheral surface 21113 of the first anti-corrosion layer. A protective coating 26 covers at least a portion of the outer surface 21133 of the third anti-corrosion layer. By providing a corner wall 2113 that connects the end wall 2112 and the side wall 2111, the risk of stress concentration at the connection point between the end wall 2112 and the side wall 2111 can be reduced. By covering at least a portion of the outer surface 21133 of the third anti-corrosion layer with the protective coating 26, the protective coating 26 can cover cracks generated in the third anti-corrosion layer 21132 during processing. This helps reduce the risk of electrolyte spilled during injection seeping into the third substrate 21131, alleviates rusting of the third substrate 21131, and improves the lifespan of the cylindrical battery cell 20.

[0242] Along the axial direction of the cylindrical battery cell 20, in the direction from the second substrate 21122 to the second anti-corrosion layer 21123, the protective coating 26 does not extend beyond the outer surface 21124 of the second anti-corrosion layer. By ensuring that the protective coating 26 does not extend beyond the outer surface 21124 of the second anti-corrosion layer in the direction from the second substrate 21122 to the second anti-corrosion layer 21123, on the one hand, it helps to reduce the risk of interference between the protective coating 26 and other components, and reduces the risk of damage to the protective coating 26. On the other hand, it helps to reduce space occupation and improve the energy density of the cylindrical battery cell 20.

[0243] The protective coating 26 has a ring-shaped structure, and at least a portion of the protective coating 26 is disposed around the outer peripheral surface 21113 of the first anti-corrosion layer. The fact that the protective coating 26 is disposed around the outer peripheral surface 21113 of the first anti-corrosion layer allows it to protect the sidewall 2111 along the circumference of the cylindrical battery cell 20, which improves the protective effect of the protective coating 26, helps alleviate the rusting of the first substrate 21111, and helps extend the lifespan of the cylindrical battery cell 20.

[0244] Along the axial direction of the cylindrical battery cell 20, the protective coating 26 is spaced apart from one end of the sidewall 2111 opposite to the end wall 2112. The area of ​​the first anti-corrosion layer 21112 near the end of the sidewall 2111 opposite to the end wall 2112 has a lower risk of cracking during processing. Furthermore, due to its distance from the end wall 2112, the risk of spilled electrolyte seeping into the first substrate 21111 is lower. Therefore, the risk of rusting in the area of ​​the first substrate 21111 near the end of the sidewall 2111 opposite to the end wall 2112 is lower. By maintaining a distance between the protective coating 26 and the end of the sidewall 2111 opposite to the end wall 2112 along the axial direction of the cylindrical battery cell 20, it is beneficial to reduce the production cost of the cylindrical battery cell 20.

[0245] 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: Electrode assembly; The housing contains the electrode assembly. The housing includes an end wall and a side wall. The side wall surrounds the end wall and includes a first substrate and a first anti-corrosion layer. The first anti-corrosion layer is disposed on the outer surface of the first substrate. The end wall includes a second substrate and a second anti-corrosion layer. The second anti-corrosion layer is disposed on the outer surface of the second substrate. The first substrate and the second substrate are integrally formed, and the first anti-corrosion layer and the second anti-corrosion layer are integrally formed. The material of the first substrate and the second substrate includes steel. The end wall is provided with a liquid injection hole, or the end wall is provided with an electrode terminal, and the electrode terminal is provided with a liquid injection hole. The protective coating has a ring structure, with at least a portion of the protective coating surrounding the outer peripheral surface of the first anti-corrosion layer. Along the axial direction of the cylindrical battery cell, the protective coating extends at least to one end of the outer peripheral surface of the first anti-corrosion layer near the second anti-corrosion layer.

2. The cylindrical battery cell according to claim 1, characterized in that, The outer peripheral surface of the first anti-corrosion layer is provided with a recess, and a portion of the protective coating is accommodated within the recess.

3. The cylindrical battery cell according to claim 1, characterized in that, The outer casing includes a corner wall, the corner wall includes a third substrate and a third anti-corrosion layer, the third anti-corrosion layer is disposed on the outer surface of the third substrate, the material of the third substrate includes steel, the third substrate connects the first substrate and the second substrate, the first substrate, the second substrate and the third substrate are integrally formed, the third anti-corrosion layer connects the first anti-corrosion layer and the second anti-corrosion layer, the first anti-corrosion layer, the second anti-corrosion layer and the third anti-corrosion layer are integrally formed; The outer surface of the third anti-corrosion layer is connected to the outer surface of the second anti-corrosion layer and the outer peripheral surface of the first anti-corrosion layer, and the protective coating covers at least a portion of the outer surface of the third anti-corrosion layer.

4. The cylindrical battery cell according to claim 3, characterized in that, The outer surface of the third anti-corrosion layer includes a first end and a second end, the first end being connected to the outer peripheral surface of the first anti-corrosion layer, and the second end being connected to the outer surface of the second anti-corrosion layer; The protective coating includes a first portion disposed on the outer peripheral surface of the first anti-corrosion layer and a second portion disposed on the outer surface of the third anti-corrosion layer. The first portion and the second portion are connected. Along the outer surface of the third anti-corrosion layer from the first end to the second end, the distance between the outer surface of the second portion and the outer surface of the third anti-corrosion layer gradually decreases.

5. The cylindrical battery cell according to claim 3, characterized in that, The protective coating completely covers the outer surface of the third anti-corrosion layer.

6. The cylindrical battery cell according to claim 5, characterized in that, Along the axial direction of the cylindrical battery cell, in the direction from the second substrate to the second anti-corrosion layer, the protective coating does not extend beyond the outer surface of the second anti-corrosion layer.

7. The cylindrical battery cell according to claim 1, characterized in that, The protective coating includes a first portion disposed on the outer peripheral surface of the first anti-corrosion layer. The first portion includes a first region and a second region. Along the axial direction of the cylindrical battery cell, the first region has a third end and a fourth end opposite to each other. The third end is connected to the second region, and the fourth end extends to one end of the outer peripheral surface of the first anti-corrosion layer near the second anti-corrosion layer. Along the direction from the fourth end to the third end, the distance between the outer surface of the second region and the outer peripheral surface of the first anti-corrosion layer gradually decreases.

8. The cylindrical battery cell according to claim 7, characterized in that, The first region has a first surface that is away from the outer peripheral surface of the first anti-corrosion layer, and the second region has a transition surface that connects the first surface and the outer peripheral surface of the first anti-corrosion layer. The transition surface is an inclined surface.

9. The cylindrical battery cell according to claim 8, characterized in that, The angle between the transition surface and the axis of the cylindrical battery cell is α, where α ≤ 60°.

10. The cylindrical battery cell according to claim 7, characterized in that, The first region has a first surface that is opposite to the outer peripheral surface of the first anti-corrosion layer. Along the radial direction of the cylindrical battery cell, the distance between the first surface and the outer peripheral surface of the first anti-corrosion layer is H, which satisfies: 3μm≤H≤100μm.

11. The cylindrical battery cell according to claim 10, characterized in that, 5μm≤H≤20μm.

12. The cylindrical battery cell according to claim 1, characterized in that, The protective coating includes a first portion disposed on the outer peripheral surface of the first anti-corrosion layer along the axial direction of the cylindrical battery cell. The size of the first portion is L, which satisfies: 0.5mm≤L≤10mm.

13. The cylindrical battery cell according to claim 12, characterized in that, 1mm≤L≤5mm.

14. The cylindrical battery cell according to any one of claims 1-13, characterized in that, Along the axial direction of the cylindrical battery cell, the protective coating is at a distance from the end of the sidewall that is opposite to the end wall.

15. The cylindrical battery cell according to any one of claims 1-13, characterized in that, The protective coating comprises a metallic material, the electrode potential of which is lower than that of steel.

16. The cylindrical battery cell according to claim 15, characterized in that, The mass percentage of the metallic material is greater than or equal to 10%.

17. The cylindrical battery cell according to any one of claims 1-13, characterized in that, The protective coating comprises petroleum sulfonate.

18. A battery device, characterized in that, Includes the cylindrical battery cell according to any one of claims 1-17.

19. An electrical appliance, characterized in that, Includes a cylindrical battery cell according to any one of claims 1-17, the cylindrical battery cell being used to provide electrical energy to the electrical device.

Images