Cylindrical battery cell, battery and power-consuming device

Abstract

Cylindrical battery cell comprising an electrolyte solution, an electrode assembly and a housing, wherein the housing accommodates the electrolyte solution and the electrode assembly, wherein: the electrolyte solution comprises an electrolyte salt, wherein the electrolyte salt comprises a hexafluorophosphate; the housing comprises a housing base body and a film layer, wherein the film layer is provided at least on one surface of the housing base body facing the electrode assembly, and wherein a base element of the film layer is a nickel element.

Description

CROSS-REFERENCE TO RELATED REGISTRATION

[0001] The present application claims priority over the Chinese patent applications under No. 202410543473.X and entitled “Cylinder battery cell, battery and power-consuming device”, which were filed with the State Intellectual Property Office in China on April 30, 2024 and are incorporated by reference in their entirety as part of the present application. TECHNICAL AREA

[0002] The present application relates to the field of rechargeable and dischargeable batteries, in particular a cylindrical battery cell, a battery and a power-consuming device. STATE OF THE ART

[0003] Battery cells are characterized by their high capacity and are therefore frequently used in electronic devices. Examples include mobile phones, laptops, battery-powered cars, electric vehicles, electric airplanes, electric boats, electric toy vehicles, electric toy boats, electric toy airplanes, power tools, and so on.

[0004] With the development of the battery cell sector and the gradual increase in battery performance requirements, the reliability and cycle performance of battery cells must be further improved. REVELATION OF THE INVENTION

[0005] The present application provides a cylindrical battery cell, a battery, and a power-consuming device. In the embodiments of the present application, the reliability and cycle performance can be improved when using a cylindrical battery cell.

[0006] A first aspect of the embodiments of the present application provides a cylindrical battery cell comprising an electrolyte solution, an electrode assembly and a housing, wherein the housing accommodates the electrolyte solution and the electrode assembly, wherein the electrolyte solution comprises an electrolyte salt, wherein the electrolyte salt comprises a hexafluorophosphate; wherein the housing comprises a housing base body and a film layer, wherein the film layer is provided at least on one surface of the housing base body facing the electrode assembly, and wherein a base element of the film layer is a nickel element.

[0007] Consequently, in the embodiment of the present application, the base element of the film layer is the nickel element, thus significantly improving the acid corrosion resistance of the film layer. Furthermore, if the cylindrical battery cell comprises a hexafluorophosphate, the nickel element can also effectively improve the acid corrosion resistance of the film layer, thereby reducing the risk of metal ion generation through metal corrosion in the casing. Moreover, the casing of the cylindrical battery cell can effectively distribute the force within a system, so that the casing is subjected to a uniform force and does not deform easily, which contributes to improved reliability in the use of the cylindrical battery cell and cycle performance, etc. In the embodiments of the present application, the base element is the element that constitutes the largest proportion in the film layer.

[0008] In some embodiments, the molar concentration of hexafluorophosphate is less than or equal to 1.2 mol / L. The molar concentration of hexafluorophosphate is within the above range, which further reduces the corrosion effect on the casing and improves the reliability of use, cycle performance, etc., of the cylindrical battery cell.

[0009] In some embodiments, the molar concentration of hexafluorophosphate is less than or equal to 0.9 mol / L. The molar concentration of hexafluorophosphate is within the above range, which further reduces the corrosion effect on the casing and improves the reliability of use, cycle performance, etc., of the cylindrical battery cell.

[0010] In some embodiments, the molar concentration of hexafluorophosphate ranges from 0.2 mol / L to 0.8 mol / L. The molar concentration of hexafluorophosphate is within the above range, which further improves the reliability of use, cycle performance, etc., of the cylindrical battery cell.

[0011] In some embodiments, the molar concentration of hexafluorophosphate is 0.3 mol / L to 0.7 mol / L. The molar concentration of hexafluorophosphate is within the above range, which further improves the reliability of use, cycle performance, etc., of the cylindrical battery cell.

[0012] In some embodiments, the film layer thickness ranges from 1.5 µm to 6.0 µm. When the film layer thickness is within the above range, it is advantageous to increase the corrosion resistance of the film layer, thereby improving the reliability of use and the cycle performance, etc., of the cylindrical battery cell.

[0013] In some embodiments, the film layer thickness is 2.0 µm to 4.0 µm. When the film layer thickness is within the above range, it is advantageous to increase the corrosion resistance of the film layer, thereby improving the reliability of use and the cycle performance, etc., of the cylindrical battery cell.

[0014] In some embodiments, the percentage by mass of the nickel element in the film layer is 70 wt.% to 100 wt.%. When the percentage by mass of the nickel element is in the above range, the corrosion resistance of the film layer is improved, which can increase the reliability of use and the cycle performance, etc., of the cylindrical battery cell.

[0015] In some embodiments, the percentage by mass of the nickel element in the film layer is 80 wt.% to 95 wt.%. When the percentage by mass of the nickel element is in the above range, the corrosion resistance of the film layer is improved, which can increase the reliability of use and the cycle performance, etc., of the cylindrical battery cell.

[0016] In some embodiments, the film layer further comprises an iron element, wherein the percentage by mass of the iron element in the film layer is 0.1 wt.% to 10 wt.%, optionally 1 wt.% to 5 wt.%. If the percentage by mass of the iron element is in the above range, the electrical conductivity of the housing can be effectively improved, which is advantageous for electron transfer.

[0017] In some embodiments, the film layer further comprises a carbon element, wherein the percentage by mass of the carbon element in the film layer is 0.1 wt.% to 15 wt.%, optionally 4 wt.% to 12 wt.%. If the percentage by mass of the carbon element is in the above range, the electrical conductivity of the housing can be effectively improved, which is advantageous for electron transfer.

[0018] In some embodiments, the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt is 0.06 to 6. When the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt is within the above range, the thermal stability of the electrolyte salt is improved, and it is less susceptible to acid corrosion through thermal decomposition. Furthermore, the electrochemical stability of the electrolyte salt is excellent, which can further improve the stability of the electrolyte salt and increase the reliability of use, cycle life, etc., of the battery cell.

[0019] In some embodiments, the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate is 0.2 to 2. If the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt is in the above range, the stability of the electrolyte salt can be further improved, thereby increasing the reliability of use as well as the cycle performance, etc., of the cylindrical battery cell.

[0020] In some embodiments, the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate is 0.3 to 1.5. If the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt is in the above range, the stability of the electrolyte salt can be further improved, thereby increasing the reliability of use as well as the cycle performance, etc., of the cylindrical battery cell.

[0021] In some embodiments, the molar concentration of the electrolyte salt is 0.5 mol / L to 2 mol / L. When the molar concentration of the electrolyte salt is in the above range, it is advantageous to further improve the stability of the electrolyte salt, the reliability of use, and the cycle performance, etc., of the battery cell. It is also advantageous to improve the liquid-phase transfer capability of the active ions, thereby improving the kinetic performance of the battery cell.

[0022] In some embodiments, the molar concentration of the electrolyte salt is 0.6 mol / L to 1.5 mol / L. When the molar concentration of the electrolyte salt is in the above range, it is advantageous to further improve the kinetic performance of the battery cell.

[0023] In some embodiments, the sulfonamide salt comprises an anion represented by formula A, where in formula A R1 and R2 each independently comprise a halogen atom or a C1 to C6 haloalkyl group.

[0024] As a result, the thermal stability of the sulfonamide salt in the above material is excellent in the embodiments of the present application, which reduces the corrosion of the electrolyte salt on the casing and improves the reliability of use and cycle performance, etc., of the battery cell.

[0025] In some embodiments, the halogen atom comprises a fluorine atom.

[0026] In some embodiments, the C1 to C6 haloalkyl group comprises a C1 to C6 fluoroalkyl group.

[0027] In some embodiments, in formula A, R1 and R2 each independently comprise a fluorine atom or a C1 to C3 fluoroalkyl group.

[0028] In some embodiments, the anion shown in formula A comprises one or more of the anions shown in formulas A-1 to A-5,

[0029] In some embodiments, the anion shown in formula A comprises one or more of the anions shown in formulas A-1 to A-2,

[0030] In some embodiments, the base material of the housing body is made of steel. The mechanical strength of the housing body made of this material is excellent and it is not easily deformed, which can further improve the reliability of the cylindrical battery cell.

[0031] In some embodiments, the electrode assembly comprises an anode foil, wherein the anode foil includes an anode collector and an anode film layer provided on at least one side of the anode collector and containing an active anode material, the active anode material comprising a silicon element. If the mass fraction of the silicon element is within the range mentioned above, the energy density of the cylindrical battery cell can be improved, and the cylindrical structure of the casing can have an inhibiting effect on the expansion of the electrode assembly, resulting in a more uniform force distribution on the casing. This makes the casing less prone to deformation, thereby improving the structural stability of the casing and increasing the reliability of the cylindrical battery cell.

[0032] In some embodiments, the percentage by mass of the silicon element in the anode film layer ranges from 1 wt.% to 32 wt.%. When the mass by mass of the silicon element is within the above range, the energy density of the cylindrical battery cell can be improved, and the reliability of its use can be enhanced.

[0033] In some embodiments, the electrolyte solution comprises a chain ester solvent, wherein the percentage by mass of the chain ester solvent in the electrolyte solution is greater than or equal to 25.5 wt.%.

[0034] Consequently, in the embodiments of the present application, the percentage by mass of the chain ester solvent is more than or equal to 25.5 wt.%, which results in a relatively high electrical conductivity of the electrolyte solution, which is beneficial for improving the liquid-phase transfer capability of the active ions, for improving the fast charging and discharging capability of the battery cell and thus for improving the multiplication performance of the battery cell.

[0035] In some embodiments, the percentage by mass of the chain ester solvent in the electrolyte solution is 25.5 wt% to 76.5 wt%. When the percentage by mass of the chain ester solvent is within the above range, it can further improve the multiplication performance and reliability of the battery cell, and it can also further improve the cycle performance of the battery cell.

[0036] In some embodiments, the percentage by mass of the chain ester solvent in the electrolyte solution is 25.5 wt% to 70 wt%. When the percentage by mass of the chain ester solvent is within the above range, it can further improve the multiplication performance and reliability of the battery cell, and it can also further improve the cycle performance of the battery cell.

[0037] In some embodiments, the percentage by mass of the chain ester solvent in the electrolyte solution is 42.5 wt% to 70 wt%. When the percentage by mass of the chain ester solvent is within the above range, it can further improve the multiplication performance and reliability of the battery cell, and it can also further improve the cycle performance of the battery cell.

[0038] In some embodiments, the chain ester solvent comprises a chain carbonate ester, wherein the percentage by mass of the chain carbonate ester in the electrolyte solution is 4 wt% to 70 wt%. When the percentage by mass of the chain carbonate ester is in the above range, it is able to improve the electrical conductivity of the electrolyte solution, improve the liquid-phase kinetic transfer performance of the electrolyte solution, and further improve the multiplication performance and reliability of the battery cell.

[0039] In some embodiments, the percentage by mass of the chain carbonate ester in the electrolyte solution ranges from 4 wt% to 42.5 wt%. When the percentage by mass of the chain carbonate ester is within the above range, it is able to improve the electrical conductivity of the electrolyte solution, enhance the liquid-phase kinetic transfer performance of the electrolyte solution, and further improve the multiplication performance and reliability of the battery cell.

[0040] In some embodiments, the chain carbonate ester comprises a compound represented in formula I, where in formula I R11 and R12 each independently comprise a C1 to C3 alkyl group or a C1 to C3 haloalkyl group.

[0041] Consequently, if the chain carbonate ester in the embodiments of the present application is the above material, it is able to further improve the multiplication performance and reliability of the use of the battery cell.

[0042] In some embodiments, in formula A, R11 and R12 each independently comprise a C1 to C3 alkyl group or a C1 to C3 fluoroalkyl group.

[0043] In some embodiments, the chain carbonate ester comprises one or more of the compounds shown in Formula I-1 to Formula I-6,

[0044] In some embodiments, the chain carbonate ester comprises a compound represented in formula 1-1,

[0045] In some embodiments, the chain ester solvent further comprises a chain carboxylic acid ester, wherein the percentage by mass of the chain carboxylic acid ester in the electrolyte solution is 4 wt.% to 70 wt.%. When the chain carboxylic acid ester and the chain carbonate ester are used in combination, it is able to improve the electrical conductivity of the electrolyte solution, improve the liquid-phase transfer kinetics of the electrolyte solution, and further improve the multiplication performance and reliability of the battery cell.

[0046] In some embodiments, the percentage by mass of the chain carboxylic acid ester in the electrolyte solution ranges from 8.5 wt% to 60 wt%. When the percentage by mass of the chain carboxylic acid ester in the electrolyte solution is within the above range, it is able to improve the electrical conductivity of the electrolyte solution, enhance the liquid-phase transfer kinetics of the electrolyte solution, and further improve the multiplication performance and reliability of the battery cell.

[0047] In some embodiments, the chain carboxylic acid ester comprises a compound represented in formula II, where in Formula II R 21 comprises a hydrogen atom, a halogen atom, a C1 to C3 alkyl group or a C1 to C3 haloalkyl group; R 22 comprises a C1 to C3 alkyl group or a C1 to C3 haloalkyl group.

[0048] Consequently, when the chain carbonate ester and the chain carboxylic acid ester in the above material are used in combination in the embodiments of the present application, it is able to further improve the multiplication performance and reliability of the use of the battery cell.

[0049] In some embodiments, R comprises 21 a hydrogen atom, a fluorine atom, a C1 to C3 alkyl group or a C1 to C3 fluoroalkyl group.

[0050] In some embodiments, R comprises 22 a C1 to C3 alkyl group or a C1 to C3 fluoroalkyl group.

[0051] In some embodiments, the chain carboxylic acid ester comprises one or more of the compounds shown in Formula II-1 to Formula II-6,

[0052] In some embodiments, the chain carboxylic acid ester comprises one or more of the compounds shown in Formula II-2 and in Formula II-3,

[0053] In some embodiments, the chain carbonate ester comprises a compound represented in formula I-1, wherein the percentage mass fraction of the compound represented by formula I-1 in electrolyte solution is 8.5 wt.% to 35 wt.%; wherein the chain carboxylic acid ester comprises the compounds shown in formula II-2 and in formula II-3, wherein the percentage by mass of the compounds shown in formula II-2 and in formula II-3 in electrolyte solution is 20 wt.% to 55 wt.%;

[0054] In some embodiments, the housing comprises a housing body and an end cap, wherein the housing body comprises a side wall and an end wall connected to the side wall, wherein the housing body has an opening, wherein the end cap is connected to the side wall and covers the opening, and wherein the end cap and the end wall are opposite each other along an axial direction of the cylindrical battery cell.

[0055] In some embodiments, the base material of the side wall is made of steel, with a thickness of 0.30 mm to 1.2 mm. When the side wall thickness is within the above range, it has higher strength and greater compressive strength, effectively reducing the risk of side wall deformation, decreasing the risk of battery cell bulging, and thus improving the reliability of the battery cell's use.

[0056] In some embodiments, the sidewall thickness is 0.30 mm to 0.55 mm. If the sidewall thickness is within the above range, the risk of sidewall deformation and battery cell bulging can be effectively reduced, thus improving the reliability of battery cell use.

[0057] In some embodiments, the side wall and the end wall form a single-piece molded structure.

[0058] In some embodiments, the end cap is provided with a pressure relief mechanism. Under the influence of internal pressure, the pressure relief mechanism deforms to connect the interior of the housing to the exterior, allowing the gas inside the housing to escape and thus reducing the risk of battery cell explosion.

[0059] In some embodiments, the pressure relief mechanism includes a weak section, the base material of which is steel, with a thickness of 0.01 mm to 0.3 mm. When the thickness of the weak section is within the above range, it exhibits higher strength and greater pressure resistance, which can effectively improve the pressure resistance of the battery cell and the reliability of its use.

[0060] In some embodiments, the thickness of the weak section is 0.05 mm to 0.2 mm. If the thickness of the weak section is within the above range, the reliability of the battery cell's use can be further improved.

[0061] In some embodiments, the end cap is provided with a concave section, where the bottom wall of the concave section is the weak point. This structural shape is simple and convenient to process.

[0062] In some embodiments, the cylindrical battery cell is further provided with an electrode connection on the end wall, wherein the cylindrical battery cell comprises an electrode assembly which is received in the housing body, wherein the electrode assembly comprises a first electrode tab and a second electrode tab of opposite polarity, wherein the first electrode tab is electrically connected to the end wall, while the second electrode tab is electrically connected to the electrode connection.

[0063] In some embodiments, the size of the housing along its own axial direction is 1.3 to 2.5 times the size of the housing along a radial direction of the cylindrical battery cell.

[0064] In some embodiments, the size of the housing along the axial direction of the cylindrical battery cell is 50mm to 150mm.

[0065] In some embodiments, the size of the housing along the radial direction of the cylindrical battery cell is 40 mm to 80 mm.

[0066] A second aspect of the embodiments of the present application further provides a battery, the battery comprising a cylindrical battery cell according to one of the embodiments of the first aspect of the present application.

[0067] A third aspect of the embodiments of the present application further provides a power-consuming device comprising a battery according to one of the embodiments of the second aspect of the present application. PRESENTATION OF THE INVENTION

[0068] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings, which are to be used in the embodiments of the present application, are briefly described below. Of course, the accompanying drawings described below are only some of the embodiments of the present application, and other accompanying drawings can be derived from the accompanying drawings by a person with normal technical knowledge without any creative effort. Fig.Figure 1 shows a schematic representation of the structure of a vehicle according to some embodiments of the present application; Fig. Figure 2 shows a schematic exploded view of a battery according to some embodiments of the present application; Fig. Figure 3 shows a schematic exploded view of a battery module according to Fig. 2; Fig. Figure 4 shows a schematic representation of the structure of a cylindrical battery cell according to some embodiments of the present application; Fig. Figure 5 shows a schematic exploded view of the cylindrical battery cell according to some embodiments of the present application; Fig. 6 shows a schematic sectional view of the cylindrical battery cell according to some embodiments of the present application; Fig. Figure 7 shows an enlarged schematic representation of the cylindrical battery cell of A in Fig. 6;

[0069] The attached drawings may not be to scale. Reference symbol list:

[0070] X. Axial direction; Y. Radial direction; 1. Vehicle; 2. Battery; 3. Control unit; 4. Engine; 5. Box; 5a. First box section; 5b. Second box section; 5c. Receiving compartment; 6. Battery module; 7. Cylindrical battery cell; 10. Electrode assembly; 111. First electrode tab; 112. Second electrode tab; 12. Main body section; 20. Housing; 21. Housing body; 211. End wall; 212. Side wall; 22. End cap; 220. Pressure relief mechanism; 221. Concave section; 222. Weak section; 30. Electrode connection; 40. Current collector element. SPECIFIC EXECUTION FORMS

[0071] In the following, exemplary embodiments of the cylindrical battery cell, the battery, and the power-consuming device of the present application are disclosed in detail with corresponding reference to the accompanying drawings. However, there will be instances where an unnecessarily detailed description is omitted. For example, detailed descriptions of things that are already well known and repeated descriptions of the same structure are omitted. This is to avoid making the following description unnecessarily long and to facilitate understanding by the person skilled in the art. Furthermore, the accompanying drawings and the following description serve to enable the person skilled in the art to fully understand the present application and are not intended to limit the subject matter specified in the claims.

[0072] The "range" disclosed here is defined in terms of a lower bound and an upper bound, with a particular range being defined by selecting a lower bound and an upper bound that establish the limits of that range. Ranges defined in this way can include or exclude end values ​​and can be combined in any way; that is, any lower bound can be combined with any upper bound to form a range. For example, if a range of 60-120 and 80-110 is specified for a particular parameter, then a range of 60-110 and 80-120 is also to be expected. Furthermore, if the minimum values ​​of 1 and 2 and the maximum values ​​of 3, 4, and 5 are specified, then the following ranges can be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.Unless otherwise specified, the range "ab" denotes any combination of real numbers between a and b, where both a and b are real numbers. For example, the range "0-5" means that all real numbers between 0 and 5 are listed here, and 0-5 is simply a shorthand representation of the combination of these values. Furthermore, stating that a parameter is an integer ≥ 2 is equivalent to stating that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on.

[0073] Unless expressly stated otherwise, all embodiments and optional embodiments of the present application may be combined to form new technical solutions.

[0074] Unless expressly stated otherwise, all technical features of the present application, as well as optional technical features, may be combined to form a new technical solution.

[0075] Unless expressly stated otherwise, all steps of the present application may be carried out sequentially or randomly, preferably sequentially. For example, the phrase "procedure comprising steps (a) and (b)" means that the procedure may include steps (a) and (b) carried out one after the other, or that it may include steps (b) and (a) carried out one after the other. The indication that the procedure may also include step (c) means, for example, that step (c) may be added to the procedure in any order; e.g., the procedure may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b).

[0076] The reference to "exemplarities" in the present application means that certain features, structures, or properties described in connection with exemplary embodiments may be included in at least one exemplary embodiment of the present application. The presence of the expression in different places in the description does not necessarily refer to the same exemplary embodiment, nor does it constitute a separate or alternative exemplary embodiment that mutually excludes other exemplary embodiments.

[0077] In the description of this application, it should be noted that the terms, e.g., "mounted," "connected," "attached," are to be understood broadly, unless expressly stated otherwise and limited, e.g., as either a permanent connection, a detachable connection, or a connection in one piece; a direct connection, or an indirect connection via an intermediate medium, or a connection within two elements. The specific meaning of the above terms in this application is clear to a person competent in the field.

[0078] The term “and / or” in the present application merely describes an associative relationship between the associated objects and indicates that three types of relationships are possible, e.g., A and / or B, which can mean that A exists alone, that both A and B exist, and that B exists alone. Furthermore, the symbol “ / *” in the present application generally indicates that the associated objects are in an “or” relationship.

[0079] In the embodiments of the present application, the same symbols denote the same parts, and for the sake of simplicity, detailed descriptions of the same parts in different embodiments are omitted. The dimensions (thickness, length, width, etc.) of the various components in the embodiments of the present application and the overall thickness, length, width, etc., of the integrated device shown in the accompanying drawings are merely exemplary and are not intended to limit the present application.

[0080] The term "multiple" as used in the present application refers to more than two (including two). In the embodiments of the present application, the battery cell can be a secondary battery, i.e., a battery cell that can be recharged after the battery cell has been discharged, so that the active material can be reactivated and used again.

[0081] The battery cell may contain, but is not limited to, a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium-metal battery cell, a sodium-metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, and the like.

[0082] The battery cell can, for example, be a cylindrical battery cell, and cylindrical battery cell means a battery cell whose shape has a cylindrical structure or is similar to a cylindrical structure.

[0083] The batteries mentioned in the embodiments of the present application may comprise one or more battery cells in order to achieve a higher voltage and capacity.

[0084] In some embodiments, the battery can be a battery module; in the case of multiple batteries, the multiple battery cells are arranged and attached in such a way that they form a battery module.

[0085] In some embodiments, the battery may be a battery pack comprising a box and a battery cell, with the battery cell or battery module being contained within the housing.

[0086] In some embodiments, the box can be part of the vehicle's chassis structure. For example, parts of the box can be at least part of the vehicle's floor, or parts of the box can be at least part of a cross member and a longitudinal member of the vehicle.

[0087] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, and the like.

[0088] The battery cell comprises an electrolyte solution and a casing. The electrolyte solution contains an electrolyte salt such as hexafluorophosphate, which has poor thermal stability and tends to decompose, forming hydrofluoric acid (HF). HF can corrode the casing, particularly the metal casing, posing a risk to the reliability of the cylindrical battery cell. Furthermore, metal ions generated by corrosion of the metal casing may also be present in the electrolyte solution, which can negatively affect the battery cells, for example, by reducing their cycle life and storage capacity.

[0089] In light of this, the embodiments of the present application provide a cylindrical battery cell. The housing of the cylindrical battery cell comprises a housing base body and a film layer, wherein the base element of the film layer is the nickel element, thus significantly improving the acid corrosion resistance of the film layer. If the cylindrical battery cell further comprises a hexafluorophosphate, the nickel element can also effectively improve the acid corrosion resistance of the film layer, thereby reducing the risk of metal ion generation through metal corrosion in the housing, which contributes to improving the reliability in use of the cylindrical battery cell and its cycle performance, etc.

[0090] The embodiments described in the present application describe a cylindrical battery cell suitable for batteries and power-consuming devices with batteries.

[0091] The cylindrical battery cell, the battery, and the power-consuming device disclosed in the embodiments of this application can be used in power-consuming devices that use batteries as a power source or in various energy storage systems that use batteries as an energy storage element. The power-consuming device can be, among other things, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, an electric bicycle, an electric vehicle, a ship, a spacecraft, and the like. Electric toys can include stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric boat toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0092] For the sake of simplicity, the following exemplary embodiments are presented using the power-consuming device as an example of a vehicle.

[0093] Fig. Figure 1 shows a schematic representation of the structure of a vehicle according to some embodiments of the present application.

[0094] As in Fig. As shown in Figure 1, vehicle 1 is equipped with a battery 2 inside. The battery 2 can be located on the underside, at the front, or at the rear of vehicle 1. The battery 2 can be used to power vehicle 1. For example, the battery 2 can be used as the operating power source for vehicle 1.

[0095] The vehicle 1 may further comprise a control unit 3 and a motor 4, wherein the control unit 3 serves to control the battery 2 in order to supply energy to the motor 4, e.g. for the operating energy requirements of the vehicle 1 for starting, navigating and driving.

[0096] In some embodiments of the present application, the battery 2 can be used not only as an operating energy source for the vehicle 1, but also as a propulsion energy source for the vehicle 1, instead of or partially instead of heating oil or natural gas to provide propulsion energy for the vehicle 1.

[0097] Fig. Figure 2 shows a schematic exploded view of a battery according to some embodiments of the present application. As in Fig. As shown in Figure 2, battery 2 comprises a box 5 and a cylindrical battery cell (in Fig.2 not shown), wherein the cylindrical battery cell is housed in box 5.

[0098] The box 5 serves to hold the cylindrical battery cell, and the box 5 can have various structures. In some embodiments, the box 5 can comprise a first box section 5a and a second box section 5b, wherein the first box section 5a and the second box section 5b overlap each other and together define a receiving space 5c for holding the cylindrical battery cells. The second box section 5b can be a hollow structure with an opening at one end. The first box section 5a is a plate-shaped structure, and the first box section 5a covers an opening side of the second box section 5b to form a box 5 with the receiving space 5c.Both the first box section 5a and the second box section 5b can also be hollow structures with an opening on one side, the opening side of the first box section 5a covering the opening side of the second box section 5b to form the box 5 with a receiving chamber 5c. Naturally, the first box section 5a and the second box section 5b can have different structures, such as cylindrical, rectangular, and the like.

[0099] To improve the sealing of the first box section 5a and the second box section 5b when they are connected, a sealing element, such as a sealant, a sealing ring and the like, may also be provided between the first box section 5a and the second box section 5b.

[0100] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be referred to as the upper box lid, and the second box section 5b can also be referred to as the lower box body.

[0101] Battery 2 can contain one or more cylindrical battery cells. If multiple cylindrical battery cells are present, they can be connected in series, parallel, or in a mixed circuit, where a mixed circuit means that the multiple cylindrical battery cells are connected in both series and parallel. The multiple cylindrical battery cells can be connected directly in series, parallel, or in a mixed circuit, and then the entire assembly formed by the multiple cylindrical battery cells is housed in box 5. Alternatively, the multiple cylindrical battery cells can first be connected in series, parallel, or in a mixed circuit to form a battery module 6, and the multiple battery modules 6 can then be connected in series, parallel, or in a mixed circuit to form a complete assembly, which is then housed in box 5.

[0102] The cylindrical battery cells can be the smallest units that make up the battery.

[0103] Fig. Figure 3 shows a schematic representation of the structure of a battery module according to Fig. 2.

[0104] In some embodiments, such as in Fig. As shown in Figure 3, there are multiple cylindrical battery cells 7, and these multiple cylindrical battery cells 7 are first connected in series, parallel, or in a mixed circuit to form a battery module 6. The multiple battery modules 6 are then connected in series or parallel in a mixed circuit to form a whole and are enclosed in the box.

[0105] The multiple cylindrical battery cells 7 in the battery module 6 can be electrically connected to one another by means of a converging component to enable a parallel, series, or mixed connection of the multiple cylindrical battery cells 7 in the battery module. The converging components can be one or more, with each converging component serving to electrically connect at least two cylindrical battery cells.

[0106] Fig. Figure 4 shows a schematic representation of the structure of a cylindrical battery cell according to some embodiments of the present application, and Fig. Figure 5 shows a schematic exploded view of the cylindrical battery cell according to Fig. 4.

[0107] As in Fig. 4 and Fig.As shown in Figure 5, in some embodiments the cylindrical battery cell 7 comprises an electrode assembly 10 and a housing 20, wherein the electrode assembly 10 is received in the housing 20.

[0108] The housing 20 has a cylindrical structure, and the housing 20 comprises a housing body 21, wherein the housing body 21 has a cylindrical structure corresponding to the shape of the electrode assembly 10, which is also a cylindrical structure.

[0109] In some embodiments, the size of the housing 20 along the axial direction X of the cylindrical battery cell 7 is 1.3 to 2.5 times the size of the housing 20 along the radial direction Y of the cylindrical battery cell 7, such as 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, or any value in a range between any two of these values. If the housing 20 meets the above size requirements, the volume expansion of the electrode assembly 10 can be effectively limited, so that the pressure force on the housing 20 is distributed more evenly, the housing 20 is less prone to deformation, and the reliability of the cylindrical battery cell 7 can be improved.

[0110] For example, the size of the housing 20 along the axial direction X is 50 mm to 150 mm, such as 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, 125 mm, 130 mm, 135 mm, 140 mm, 145 mm, 150 mm or any value in a range between two of these values.

[0111] For example, the size of the housing 20 along the radial direction Y is 40 mm to 80 mm, e.g. 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm or any value in a range between two of these values.

[0112] The electrode assembly 10 comprises a cathode and an anode. During charging and discharging of the cylindrical battery cell 7, active ions (e.g., lithium ions) are embedded and unembedded between the cathode and the anode. Optionally, the electrode assembly 10 also includes a separator element positioned between the cathode and the anode. This separator element reduces the risk of a short circuit between the cathode and the anode while allowing the active ions to pass through.

[0113] In some embodiments, the cathode can be a cathode foil, and the cathode foil can comprise a cathode collector and a cathode film layer provided on at least one surface of the cathode collector, wherein the cathode film layer comprises an active cathode material.

[0114] For example, the cathode collector has two surfaces that are opposite each other in its thickness direction, and the cathode film layer is provided on one or both of the two surfaces opposite the cathode collector.

[0115] For example, the cathode collector can be a metal foil or a composite collector. Metal foils can be made of stainless steel, copper, aluminum, nickel, charcoal concentrate, carbon, nickel, titanium, silver-plated aluminum, or stainless steel. The composite collector can consist of a polymer base layer and a metal layer. A composite collector can be formed by depositing metallic material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) onto a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0116] For example, if the cylindrical battery cell 7 of the embodiments of the present application is a lithium-ion battery, the active cathode material can comprise at least one of the following materials: a phosphate, a layered transition metal oxide, and their respective modified compounds. Optionally, the active cathode material can comprise the layered transition metal oxide and its respective modified compound, which contributes to increasing the energy density of the cylindrical battery cell 7. However, the present application is not limited to these materials, and other conventional materials that can be used as the cathode film layer in batteries can also be used. It is possible to use only one of these active cathode materials or to use more than two in combination.

[0117] Phosphates include, for example, lithium iron phosphate (e.g., LiFePO4 (which can also be abbreviated as LFP)), a compound of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a compound of lithium manganese phosphate and carbon, a compound of lithium ferromanganese phosphate, and lithium manganese iron phosphate and carbon.

[0118] The layered transition metal oxide comprises at least one compound with the general formula of Li,Ni3Co c M d O e Ar or a modified compound thereof. 0.8 ≤ a ≤ 1.2, 0.3 ≤ b < 1, 0 < c < 1, 0 < d < 1, 1 ≤ e ≤ 2, 0 ≤ f ≤ 1, M comprises at least one of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A comprises at least one of N, F, S and Cl. Optionally, 0.5 ≤ b < 1, and further optionally, 0.75 ≤ b ≤ 0.98.

[0119] Layered transition metal oxides include, for example, at least one of the following compounds: lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi1). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 (can be abbreviated), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 (can be abbreviated), 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 (designated), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 (designated) and LiNi 0.9 Co 0.05 Mn 0.05 O2 (also known as Ni90), lithium nickel cobalt aluminum oxide (e.g. LiNi) 0.80 Co 0.15 Al 0.05O2) and modified compounds thereof and the like.

[0120] If the cylindrical battery cell 7 of the embodiments of the present application is a sodium ion battery, the active cathode material may comprise, but is not limited to, at least a sodium-containing transition metal oxide, a polyanionic material (e.g. a phosphate, a fluorophosphate, a pyrophosphate, a sulfate and the like) or a Prussian blue-like material.

[0121] For example, the active cathode material for the sodium-ion battery can include at least one of the following materials: NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 213 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3O2, NaFePO4, NaMnPO4, NaCoPO4, a Prussian blue-like material, a material with the general formula XpM'q(PO4)rOxY3-x. In the general formula X p M' q (PO4),O x Y 3-x , 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, X includes at least one of H + , Li + , N / a + , K + and NH4+, and M' is a transition metal cation, optionally at least one of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, Y is a halogen anion, optionally at least one of F, Cl and Br.

[0122] In the embodiments of the present application, the modified compound of each of the above active cathode materials can be a doped modification and / or a modification of the surface coating of the active cathode material, such as a modification of the carbon coating, a modification of the coating of a fast ionic conductor and the like.

[0123] During charging and discharging, the cylindrical battery cell 7 undergoes debedding and depletion of active ions, such as Li, and the molar Li content of the cylindrical battery cell 7 varies depending on the discharge state. In the listing of active cathode materials in the embodiments of the present application, the molar Li content represents an initial state of the material, i.e., the state before input, and the molar Li content can change when the active cathode material is inserted into the battery system after a charge and discharge cycle.

[0124] In the listing of active cathode materials in the embodiments of the present application, the molar fraction of oxygen O is only a theoretical state value; the lattice release of oxygen leads to a change in the molar fraction of oxygen O, and in practice the molar fraction of oxygen O will fluctuate.

[0125] In the embodiments of the present application, the proportion of elements in the active cathode material is of a meaning known in the art and can be determined using equipment and methods known in the art. With reference to EPA 60100-2014, it is measured, for example, by inductively coupled plasma atomic emission spectrometry (ICP-OES, instrument model: Thermo ICAP7400). First, 0.4 g of the active cathode material was weighed and 10 ml (50% concentration) of aqua regia was added. It was then placed on a plate at 180 °C for 30 minutes. After dissipation on the plate, it was fixed to a volume of 100 mL and quantitatively tested using the standard curve method.

[0126] In some embodiments, the cathode can consist of a foam metal. This foam metal can be nickel foam, copper foam, aluminum foam, a foam alloy, or carbon foam. When the foam metal is used as the cathode, its surface need not be coated with a cathode film, but it can be. For example, a lithium source material, a potassium metal, or a sodium metal can also be embedded in and / or deposited within the foam metal, with the lithium source material being a lithium metal and / or a lithium-rich material.

[0127] In some embodiments, the cathode film layer optionally comprises a conductive cathode material. The embodiments of the present application do not specifically restrict the type of conductive cathode material, and by way of example, the conductive cathode material comprises at least one of the following: superconducting carbon, conductive graphite, acetylene black, carbon black, cotinine black, carbon dots, carbon nanotubes, graphene, and carbon nanofibres. In some embodiments, the percentage by mass of the conductive cathode material in the cathode film layer is ≤ 5 wt.%.

[0128] In some embodiments, the cathode film layer optionally comprises a cathode binder. The embodiments of the present application do not expressly restrict the type of cathode binder; for example, the cathode binder may comprise at least one of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene propylene terpolymer, vinylidene fluoride-hexafluoropropylene tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resins. In some embodiments, the percentage by mass of the cathode binder in the cathode film layer is ≤5 wt.%.

[0129] The cathode film layer is typically produced by applying a cathode slurry to the cathode collector, drying, and cold pressing. The cathode slurry is usually prepared by dispersing the active cathode material, an optional conductive agent, an optional binder, and other components in a solvent and mixing thoroughly. The solvent can be, but is not limited to, N-methylpyrrolidone (NMP).

[0130] In some embodiments, the anode can be an anode foil, and the anode foil can comprise an anode collector and an anode film layer provided on at least one surface of the anode collector, wherein the anode film layer comprises an active anode material.

[0131] For example, the anode collector has two surfaces that are opposite each other in its thickness direction, and the anode film layer is provided on one or both of the two surfaces opposite the anode collector.

[0132] For example, the anode collector can be a metal foil, a foam metal, or a composite collector. The metal foil can be made of aluminum or stainless steel with a silver coating, stainless steel, copper, aluminum, nickel, or electrodes made of charcoal concentrate, carbon, nickel, or titanium. The foam metal can be nickel foam, copper foam, aluminum foam, a foam alloy, or carbon foam. The composite collector can consist of a polymer base layer and a metal layer. A composite collector can be formed by depositing metallic material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) onto a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0133] For example, the active anode material can be an active anode material known in the art for use in cylindrical battery cells 7. The active anode material can, for example, comprise at least one of the following materials: carbon material (e.g., the carbon material comprises at least one of the following: synthetic graphite, natural graphite, soft carbon, hard carbon), silicon-based material, tin-based material, and lithium titanate. The silicon-based material can comprise at least one of monolithic silicon, silicon oxides, silicon-carbon complexes, silicon-nitrogen complexes, and silicon alloys. The tin-based material can comprise at least one of monolithic tin, tin oxide compounds, and tin alloys.However, the present application is not limited to these materials, and other conventional materials that can be used as the anode film layer in batteries may also be used. It is possible to use only one of these anode film layers or to use more than two in combination.

[0134] In some embodiments, the active anode material comprises silicon elements, wherein the silicon element can be in the form of a silicon-based material; for example, the silicon-based material can comprise at least one of monolithic silicon, silicon oxides, silicon-carbon complexes, silicon-nitrogen complexes, and silicon alloys. The introduction of the silicon element can increase the energy density of the cylindrical battery cell 7.

[0135] In some embodiments, the mass fraction of the silicon element in the anode film layer is 1 wt.% to 32 wt.%, optionally 2 wt.% to 19 wt.%, and further optionally 6 wt.% to 13 wt.%. In the system of the cylindrical battery cell 7, when the mass fraction of the silicon element is in the above range, the energy density of the cylindrical battery cell 7 can be improved, and the cylindrical structure of the housing 20 can have an inhibiting effect on the expansion of the electrode assembly 10, so that the force distribution of the electrode assembly 10 on the housing 20 is more uniform, the housing 20 is not easily deformed, thereby improving the structural stability of the housing 20 and increasing the reliability of the use of the cylindrical battery cell 7.

[0136] In the embodiments of the present application, the mass fraction of the silicon element in the anode film layer is of a known technical meaning and can be tested using known technical equipment and methods. For example, the anode film is immersed in a solvent such as water, the active anode material is separated from the anode collector, and the active anode material is recovered by pumping and filtering. The silicon element fraction can be determined by placing the active anode material in an inductively coupled plasma emission spectrometer, model ICAP7400, manufactured by Thermo Fisher Scientific Company, in accordance with standard GB / T30902-2014.

[0137] In some embodiments, the anode film layer optionally comprises a conductive anode material. The embodiments of the present application do not specifically restrict the type of conductive anode material, and, by way of example, the conductive anode material may comprise at least one of the following: superconducting carbon, conductive graphite, acetylene black, carbon black, cotinine black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the percentage by mass of the conductive anode material in the anode film layer is ≤5 wt.%.

[0138] In some embodiments, the anode film layer optionally comprises an anode binder. The embodiments of the present application do not expressly restrict the type of anode binder; for example, the anode binder may comprise at least one of the following: styrene-butadiene rubber (SBR), a water-soluble unsaturated resin SR-1B, an aqueous acrylic resin (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS). In some embodiments, the percentage by mass of the anode binder in the anode film layer is ≤5 wt.%.

[0139] In some embodiments, the anode film layer optionally comprises other additives. These additives may include, for example, thickening agents such as sodium carboxymethylcellulose (CMC-Na), PTC thermistor materials, and the like. In some embodiments, the percentage by mass of these other additives in the anode film layer is ≤2 wt.%.

[0140] In some embodiments, the material of the cathode collector can be aluminum and the material of the anode collector can be copper.

[0141] In some embodiments, the separating element further comprises a separating film. The present application does not impose any specific restrictions regarding the type of separating film, and any known separating film with a porous structure and good chemical and mechanical stability can be selected.

[0142] The embodiments of the present application do not impose any specific restrictions regarding the type of separating film, and any known separating film with a porous structure and good chemical and mechanical stability can be selected.

[0143] In some embodiments, the separating film material can comprise at least one or more glass fibers, nonwoven fabrics, polyethylene, polypropylene, and polyvinylidene fluoride. The separating film can be a single-layer film or a multi-layer composite film without any particular restriction. If the insulating film is a multi-layer composite film, the materials of the layers can be the same or different without any particular restriction.

[0144] In some embodiments, the separating film may comprise a porous base film and a coating on at least one side of the porous base film, wherein the coating may comprise at least one of inorganic particles or organic particles.

[0145] The porous base film may contain one or more of polyethylene and polypropylene.

[0146] The inorganic particles have improved heat resistance and can enhance the overall heat resistance of the insulating membrane. The inorganic particles are essentially immune to oxidation and reduction reactions with the metal dendrites across the operating voltage range of the sodium-ion battery; in other words, the inorganic particles are configured to be immune to oxidation and reduction reactions with alkali metals and / or alkaline earth metals at the nominal voltage of the sodium-ion battery.

[0147] In some embodiments, the inorganic particles comprise one or more of Burmit γ-AlOOH, aluminum oxide Al2O3, aluminum hydroxide Al(OH)3, barium sulfate BaSO4, magnesium oxide MgO, magnesium hydroxide Mg(OH)2, calcium oxide CaO, cerium oxide CeO2, zirconium titanate SrTiO3, barium titanate BaTiO3 and magnesium fluoride MgF2.

[0148] In some embodiments, the organic particles comprise at least one of polystyrene, polyethylene, polyimide, melamine resin, phenolic resin, polypropylene, polyester (e.g. polyethylene terephthalate, ethyl polyethylene naphthalene dicarboxylic acid ester, polybutylene terephthalate), polyphenylene sulfide, polyarylamide, polyamidopyrimide, polyimide, copolymers of butyl acrylate and ethyl methacrylate and mixtures thereof.

[0149] In some embodiments, the cylindrical battery cell 7 further comprises an electrolyte solution.

[0150] During the charging and discharging of the battery cell, active ions are intercalated and embedded between the cathode foil and the anode foil, and the electrolyte solution acts as a conductor for active ions between the cathode foil and the anode foil. The embodiments of the present application do not impose any particular restrictions regarding the type of electrolyte solution; the embodiment can be selected according to actual requirements.

[0151] This electrolyte solution consists of an electrolyte salt and a solvent. There are no particular restrictions on the type of electrolyte salt and solvent.

[0152] In some embodiments, the electrolyte solution optionally includes an additive. This additive may, for example, include a film-forming additive for the anode and a film-forming additive for the cathode, and may also include an additive that can improve certain battery properties, such as an additive to improve the battery's overcharge performance, an additive to improve its high-temperature performance, an additive to improve its low-temperature performance, etc.

[0153] The additives include, for example, at least one of the following compounds: cyclic carbonate compounds with unsaturated bonds, sulfate compounds, sulfite compounds, sulfonolactone compounds, disulfonate compounds, nitrile compounds, aromatic compounds, isocyanate compounds, phosphonitrile compounds, acid anhydrides, cyclic anhydride compounds, phosphite compounds, phosphate compounds, boronates and carboxylic acid ester compounds.

[0154] As in the Fig. 4 and Fig. As shown in Figure 5, the electrode assembly 10 can be a wound structure or a stacked sheet structure in some embodiments, and optionally the electrode assembly 10 is a wound structure. The cathode foil and the anode foil are wound within the wound structure.

[0155] For example, multiple cathode foils and multiple anode foils can be provided separately, and multiple cathode foils and multiple anode foils can be provided in alternating layers.

[0156] In some embodiments, the housing 20 comprises a housing body 21 and an end cap 22, wherein the housing body 21 is provided with an opening and the end cap 22 is used to cover the opening.

[0157] The housing body 21 is a component that interacts with the end cap 22 to form an inner cavity of the cylindrical battery cell 7. The resulting inner cavity can be used to accommodate the electrode assembly 10, the electrolyte, and other components.

[0158] The housing body 21 and the end cap 22 can be separate components. For example, an opening can be provided in the housing body 21 to form the inner cavity of the cylindrical battery cell 7, with the end cap 22 covering the opening at the point of opening.

[0159] The end cap 22 is attached to the housing body 21 by welding, gluing, snap-lock or other means.

[0160] The housing body 21 can have an opening at one end or at both ends. In some examples, the housing 21 can be a structure with an opening on one side, and the end caps 22 are provided as a single unit and cover the housing body 21. In other examples, the housing body 21 can also be a structure with openings on both sides, and the end caps 22 are provided as two, with the two end caps 22 covering the two openings of the housing body 21.

[0161] In some embodiments, the housing body 21 comprises a side wall 212 and an end wall 211 connected to the side wall 212, wherein the end wall 211 and the end caps 22 are opposite each other along an axial direction of the cylindrical battery cell 7, the end caps 22 are sealed to the side wall 212 and the side wall 212 is arranged around the electrode assembly 10.

[0162] In some embodiments, the end wall 211 and the side wall 212 can have the same polarity.

[0163] In some embodiments, the end wall 211 and the side wall 212 can be formed in one piece, i.e., the housing body 21 is a single-piece element. Of course, the end wall 211 and the side wall 212 can also consist of two separate parts, which are then joined together by welding, riveting, gluing, or similar methods.

[0164] The appearance of the electrode assembly 10 shows that it comprises a main body section 12, a first electrode tab 111, and a second electrode tab 112, wherein the first electrode tab 111 and the second electrode tab 112 have opposite polarities and project from the main body section 12, respectively. The first electrode tab 111 is a section of the first electrode foil that is not coated with the active material layer, and the second electrode tab 112 is a section of the second electrode foil that is not coated with the active material layer. The first electrode tab 111 and the second electrode tab 112 are used to draw current from the main body section 12. The first electrode tab and the second electrode tab have opposite polarities, i.e.,One of the first and second electrode tabs is a cathode foil and the other of the first and second electrode tabs is an anode foil.

[0165] To illustrate the example, let the first electrode tab 111 be an anode foil and the second electrode tab 112 be a cathode foil; the section of the anode collector in the anode foil that is not coated with an active material layer is the anode tab, the active material coated onto the anode collector of the anode foil forms an anode film layer, and the anode film layer and the anode collector coated with the active material are part of the main body section 12. The section of the cathode collector in the cathode foil that is not coated with an active material layer is the cathode tab, the active material coated onto the cathode collector of the cathode foil forms a cathode film layer, and the cathode film layer and the cathode collector coated with the active material are part of the main body section 12.

[0166] In some embodiments, the cylindrical battery cell 7 comprises a first electrode discharge section and a second electrode discharge section, wherein the first electrode discharge section is electrically connected to the first electrode tab 111 and the second electrode discharge section is electrically connected to the second electrode tab 112.

[0167] In the axial direction of the main body section 12, the first electrode discharge section and the second electrode discharge section can also be arranged on both sides of the electrode assembly 10, or the first electrode discharge section and the second electrode discharge section are located on the same side of the electrode assembly 10, for example, the second electrode discharge section includes an electrode connection 30 which is provided insulated at the end wall 211, and the first electrode discharge section is the end wall 211.

[0168] The first electrode tab 111 and the second electrode tab 112 can extend from the same side of the main body section 12, or they can extend from opposite sides.

[0169] The first electrode tab 111 and the second electrode tab 112 can be arranged on both sides of the main body section 12 along the axial direction; in other words, the first electrode tab 111 and the second electrode tab 112 are arranged at both ends of the electrode assembly 10 along the axial direction.

[0170] Optionally, the first electrode tab 111 is wound in a plurality of turns around the central axis of the electrode assembly 10, and the first electrode tab 111 comprises a plurality of turns of the electrode tab layer. After completion of the winding, the first electrode tab 111 essentially has the form of a column, and a gap remains between two adjacent turns of the electrode tab layer. The embodiments of the present application can treat the first electrode tab 111 such that the gap between the electrode tab layers is reduced in order to facilitate the connection of the first electrode tab 111 to other conductive structures.For example, the embodiments of the present application can perform a kneading treatment on the first electrode tab 111 in order to close and join the ends of the first electrode tab 111 facing away from the main body section 12; the kneading treatment creates a dense end surface at the end of the first electrode tab 111 facing away from the main body section 12, reduces the gap between the electrode tab layers, and facilitates the connection of the first electrode tab 111 with the other conductive structures. Alternatively, the embodiments of the present application can also fill the electrically conductive material between two adjacent windings of the electrode tab layers in order to reduce the gap between the electrode tab layers.

[0171] Optionally, the second electrode tab 112 is wound in a plurality of turns around the central axis of the electrode assembly 10, and the second electrode tab 112 comprises a plurality of turns of the electrode tab layer. For example, the second electrode tabs 112 are also kneaded to reduce the gap between the electrode tab layers of the second electrode tab 112.

[0172] The first electrode tab 111 is electrically connected to the end cap 22. The first electrode tab 111 can be electrically connected to the end cap 22 directly or indirectly via other electrically conductive structures, and the end cap 22 is electrically connected to the end wall 211.

[0173] The second electrode tab 112 is electrically connected to an electrode terminal 30 of the cylindrical battery cell 7, the electrode terminal 30 being insulated and provided on the end wall 211. The second electrode tab 112 can be electrically connected to the electrode terminal 30, and can also be electrically connected to the electrode terminal 30 directly or indirectly via other electrically conductive structures.

[0174] In some embodiments, the second electrode tab 112 can be directly connected to the electrode terminal 30, for example by soldering, crimping, or otherwise connecting the electrode terminals 30. Alternatively, the second electrode tab 112 can be indirectly connected to the electrode terminal 30 via other electrically conductive components, such as the current collector element 40, in order to electrically connect the second electrode tab 112 to the electrode terminal 30.

[0175] The electrode terminal 30 is insulated to be provided on the end wall 211, so that the electrode terminal 30 and the end wall 211 can have different polarities and the electrode terminal 30 and the end wall 211 can act as different output electrodes.

[0176] The end wall 211 can be provided with an electrode discharge hole, and the electrode connection 30 is insulated in the end wall 211 and mounted in the electrode discharge hole, and the electrode discharge hole facilitates the discharge of electrical energy from the electrode assembly 10 to the outside of the housing body 21.

[0177] The central axis of the electrode assembly 10 is a virtual straight line, and the central axis of the electrode assembly 10 can pass through the electrode discharge hole or be offset from the electrode discharge hole, which is not restricted in the present application.

[0178] The electrode connection 30 can be attached to the end wall 211. The electrode connection 30 can be attached to the outside of the end wall 211 as a whole, or it can extend through the electrode discharge hole into the interior of the housing 20.

[0179] In the case where the first electrode tab 111 is an anode tab and the second electrode tab 112 is a cathode tab, the end wall 211 is a negative output electrode of the cylindrical battery cell 7, and the electrode terminal 30 is a positive output electrode of the cylindrical battery cell 7.

[0180] In some embodiments, the cylindrical battery cell 7 comprises a housing 20, an electrode assembly 10, and an electrolyte solution, wherein the housing 20 accommodates the electrode assembly 10 and the electrolyte solution, the electrolyte solution comprising an electrolyte salt, the electrolyte salt comprising a hexafluorophosphate; wherein the housing 20 comprises a housing base body and a film layer, the film layer being provided at least on one surface of the housing base body facing the electrode assembly 10, and wherein a base element of the film layer is a nickel element.

[0181] The hexafluorophosphate can comprise one or more of lithium hexafluorophosphate, sodium hexafluorophosphate, and the like. Hexafluorophosphate has good solubility and high conductivity in the organic solvent, resulting in good kinetic performance of the battery cell; and hexafluorophosphate is able to form an excellent solid electrolyte interface film (SEI film) on the surface of the anode film layer, providing excellent protection for the anode film layer.

[0182] The basic element of the film layer is the nickel element, which significantly improves the acid corrosion resistance of the film layer. Furthermore, if the cylindrical battery cell 7 comprises a hexafluorophosphate, the nickel element can also effectively improve the acid corrosion resistance of the film layer, thereby reducing the risk of metal ion generation through metal corrosion in the housing 20. In addition, the housing 20 of the cylindrical battery cell 7 can effectively distribute the force within a system, so that the housing 20 is subjected to a uniform force and does not deform easily, which contributes to improved reliability in the use of the cylindrical battery cell 7 and its cycle performance, etc. In the embodiments of the present application, the basic element is the element that constitutes the largest proportion in the film layer. The nickel element can be present in the film layer in the form of a nickel monomer or a nickel alloy, etc.may be present, and the nickel alloy can be an alloy containing nickel as the base element and iron and carbon, etc., as auxiliary elements.

[0183] In some embodiments, the molar concentration of the hexafluorophosphate is less than or equal to 1.2 mol / L, optionally less than or equal to 0.9 mol / L, optionally 0.2 mol / L to 0.8 mol / L, and further optionally 0.3 mol / L to 0.7 mol / L. The molar concentration of the hexafluorophosphate is within the above range, which further reduces the corrosion effect on the housing 20 and improves the reliability of use as well as the cycle performance, etc., of the cylindrical battery cell 7.

[0184] For example, the molar concentration of hexafluorophosphate can be 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L, 0.45 mol / L, 0.5 mol / L, 0.55 mol / L, 0.6 mol / L, 0.65 mol / L, 0.7 mol / L, 0.75 mol / L, 0.8 mol / L, 0.85 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, 1.15 mol / L, 1.2 mol / L, or any value in a range between any two of these values.

[0185] In some embodiments, the film layer thickness is 1.5 µm to 6.0 µm, optionally 2.0 µm to 4.0 µm. When the film layer thickness is within the above range, it is advantageous to increase the corrosion resistance of the film layer, thereby improving the reliability of use and the cycle performance, etc., of the cylindrical battery cell 7.

[0186] For example, the thickness of the film layer can be 1.5 µm, 1.8 µm, 2 µm, 2.5 µm, 3 µm, 3.5 µm, 4 µm, 4.5 µm, 5 µm, 5.5 µm, 6 µm, 6.5 µm or any value in a range between two of these values.

[0187] In some embodiments, the percentage by mass of the nickel element in the film layer is 70 wt.% to 100 wt.%, optionally 80 wt.% to 95 wt.%. When the percentage by mass of the nickel element is in the above range, the corrosion resistance of the film layer is improved, thereby increasing the reliability of use and the cycle performance, etc., of the cylindrical battery cell 7.

[0188] For example, the percentage by mass of the nickel element in the film layer can be 70 wt.%, 71 wt.%, 72 wt.%, 73 wt.%, 74 wt.%, 75 wt.%, 76 wt.%, 80 wt.%, 82 wt.%, 85 wt.%, 88 wt.%, 90 wt.%, 92 wt.%, 95 wt.%, 98 wt.%, 99 wt.%, 100 wt.% or any value in a range between two of these values.

[0189] In some embodiments, the film layer further comprises an iron element, wherein the percentage by mass of the iron element in the film layer is 0.1 wt.% to 10 wt.%, optionally 1 wt.% to 5 wt.%. If the percentage by mass of the iron element is in the above range, the electrical conductivity of the housing 20 can be effectively improved, which is advantageous for electron transfer.

[0190] For example, the percentage by mass of the iron element in the film layer can be 0.1 wt.%, 0.5 wt.%, 0.8 wt.%, 1 wt.%, 1.2 wt.%, 1.5 wt.%, 2 wt.%, 2.5 wt.%, 3 wt.%, 3.5 wt.%, 4 wt.%, 4.5 wt.%, 5 wt.%, 5.5 wt.%, 6 wt.%, 6.5 wt.%, 7 wt.%, 7.5 wt.%, 8 wt.%, 8.5 wt.%, 9 wt.%, 10 wt.% or any value in a range between any two of these values.

[0191] In some embodiments, the film layer further comprises a carbon element, wherein the percentage by mass of the carbon element in the film layer is 0.1 wt.% to 15 wt.%, optionally 4 wt.% to 12 wt.%. If the percentage by mass of the carbon element is in the above range, the electrical conductivity of the housing 20 can be effectively improved, which is advantageous for electron transfer.

[0192] For example, the percentage by mass of the carbon element in the film layer can be 0.1 wt.%, 0.5 wt.%, 0.8 wt.%, 1 wt.%, 1.2 wt.%, 1.5 wt.%, 2 wt.%, 2.5 wt.%, 3 wt.%, 3.5 wt.%, 4 wt.%, 4.5 wt.%, 5 wt.%, 5.5 wt.%, 6 wt.%, 6.5 wt.%, 7 wt.%, 7.5 wt.%, 8 wt.%, 8.5 wt.%, 9 wt.%, 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%, 14 wt.%, 15 wt.%, or any value in a range between any two of these values.

[0193] In some embodiments, the electrolyte salt further comprises a sulfonamide salt, and the hexafluorophosphate and the sulfonamide salt are used together, resulting in a relatively high thermal stability of the electrolyte system, which can improve the stability of the electrolyte solution and the cycle performance of the cylindrical battery cell 7.

[0194] The sulfonamide salt may comprise one or more of lithium sulfonimide and sodium sulfonimide, and the like.

[0195] In some embodiments, the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate is 0.06 to 6, optionally 0.2 to 2, and further optionally 0.3 to 1.5. When the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt is within the above range, the thermal stability of the electrolyte salt is improved, and it is less susceptible to acid corrosion through thermal decomposition. Furthermore, the electrochemical stability of the electrolyte salt is superior, which can further enhance the stability of the electrolyte salt and increase the reliability of use, cycle life, etc., of the battery cell.

[0196] For example, the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt can be 0.06, 0.08, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, 5, 5.2, 5.5, 5.8, 6 or any value in a range between any two of these values.

[0197] In some embodiments, the molar concentration of the electrolyte salt is 0.5 mol / L to 2 mol / L, optionally 0.6 mol / L to 1.5 mol / L. When the molar concentration of the electrolyte salt is in the above range, it is advantageous to further improve the stability of the electrolyte salt, the reliability of use, and the cycle performance, etc., of the battery cell. It is also advantageous to improve the liquid-phase transfer capability of the active ions, thereby improving the kinetic performance of the battery cell.

[0198] For example, the molar concentration of the electrolyte salt can be 0.5 mol / L, 0.55 mol / L, 0.6 mol / L, 0.65 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2 mol / L or any value in a range between any two of these values.

[0199] In some embodiments, when the molar concentration of the hexafluorophosphate is 0.2 mol / L to 0.8 mol / L, the film thickness is 1.5 µm to 6.0 µm. The molar concentration of the hexafluorophosphate and the film thickness are adjusted to improve the reliability and cycle performance of the cylindrical battery cells 7 in a balanced manner.

[0200] In some embodiments, when the molar concentration of the hexafluorophosphate is 0.3 mol / L to 0.7 mol / L, the film thickness is 2.0 µm to 4.0 µm. The molar concentration of the hexafluorophosphate and the film thickness are adjusted to improve the reliability and cycle performance of the cylindrical battery cells 7 in a balanced manner.

[0201] In some embodiments, when the molar concentration of hexafluorophosphate is 0.2 mol / L to 0.8 mol / L, the percentage by mass of nickel in the film layer is 70 wt.% to 100 wt.%. The molar concentration of hexafluorophosphate and the percentage by mass of nickel in the film layer are adjusted to improve the reliability and cycle performance of the cylindrical battery cells 7 in a balanced manner.

[0202] In some embodiments, when the molar concentration of hexafluorophosphate is 0.3 mol / L to 0.7 mol / L, the percentage by mass of nickel in the film layer is 80 wt.% to 95 wt.%. The molar concentration of hexafluorophosphate and the percentage by mass of nickel in the film layer are adjusted to improve the reliability and cycle performance of the cylindrical battery cells 7 in a balanced manner.

[0203] In some embodiments, when the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt is from 0.06 to 6, the film layer thickness is 1.5 µm to 6.0 µm. The electrolyte salt and the film layer thickness are adjusted to improve the reliability and cycle performance of the cylindrical battery cells 7 in a balanced manner.

[0204] In some embodiments, when the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt is 0.2 to 2, the film layer thickness is 2.0 µm to 4.0 µm. The electrolyte salt and the film layer thickness are adjusted to improve the reliability and cycle performance of the cylindrical battery cells 7 in a balanced manner.

[0205] In some embodiments, when the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt is 0.06 to 6, the percentage by mass of the nickel element in the film layer is 70 wt.% to 100 wt.%. The electrolyte salt and the percentage by mass of the nickel element are adjusted to improve the reliability and cycle performance of the cylindrical battery cells 7 in a balanced manner.

[0206] In some embodiments, when the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt is 0.2 to 2, the percentage by mass of the nickel element in the film layer is 80 wt.% to 95 wt.%. The electrolyte salt and the percentage by mass of the nickel element are adjusted to improve the reliability and cycle performance of the cylindrical battery cells 7 in a balanced manner.

[0207] In some embodiments, where the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt is 0.3 to 1.5, the layered transition metal oxide comprises at least one compound with the chemical formula of Li a Ni b Co c M d O e A fand a modified compound thereof, 0.3 ≤ b < 1, optionally 0.5 ≤ b < 1, further optionally 0.75 ≤ b ≤ 0.98. The relatively high percentage by mass of the nickel element makes the interfacial properties of the layered transition metal oxide and the electrolyte solution more active, and when the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate salt is in the above range, the sulfonamide salt is able to improve the interfacial stability of the layered transition metal oxide and the electrolyte solution, reduce the risk of a side reaction occurring, and improve the cycle performance of the cylindrical battery cell 7.

[0208] For example, b can be 0.3, 0.4, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.88, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98 or any value in a range between any two of these values.

[0209] In some embodiments, the sulfonamide salt comprises an anion represented by formula A, where in formula A R1 and R2 each independently comprise a halogen atom or a C1 to C6 haloalkyl group.

[0210] The thermal stability of the sulfonamide salt in the above material is excellent, which reduces the corrosion of the electrolyte salt on the casing 20 and improves the reliability of use and cycle performance, etc., of the battery cell.

[0211] In some embodiments, the halogen atom comprises a fluorine atom.

[0212] In some embodiments, the C1 to C6 haloalkyl group comprises a C1 to C6 fluoroalkyl group.

[0213] In some embodiments, in formula A, R1 and R2 each independently comprise a fluorine atom or a C1 to C3 fluoroalkyl group. The above material can readily dissociate active ions, and the viscosity of the electrolyte salt is relatively low, which can improve the liquid-phase transfer capability of the electrolyte solution and the kinetic performance of the electrolyte solution.

[0214] For example, the anion shown in formula A comprises one or more of the anions shown in formulas A-1 to A-5,

[0215] Optionally, the anion shown in formula A comprises one or more of the anions shown in formulas A-1 to A-2,

[0216] The film layer can provide protection for the housing base, and the housing base material can vary. For example, the base material of the housing base includes, but is not limited to, copper, iron, aluminum, steel, aluminum alloy, and similar materials. Optionally, the base material of the housing base can include steel, such as stainless steel. The mechanical strength of the above material is excellent, and it is not easily deformed, which can further improve the reliability of the cylindrical battery cell 7. In every embodiment of the present application, the base material is the predominant material, and of course, the housing base can also be made of steel.

[0217] The housing 20 comprises a housing body 21 and an end cap 22; the housing body 21 may comprise a housing base body, in which case the housing body 21 comprises a housing base body and a film layer; the end cap 22 may comprise a housing base body, in which case the end cap 22 comprises a housing base body and a film layer; and both the housing body 21 and the end cap 22 comprise a housing base body.

[0218] In some embodiments, the electrolyte solution comprises a chain ester solvent, wherein the percentage by mass of the chain ester solvent in the electrolyte solution is greater than or equal to 25.5 wt.%.

[0219] In some embodiments, the cylindrical battery cell 7 comprises a housing 20, an electrode assembly 10 and an electrolyte solution, wherein the housing 20 accommodates the electrode assembly 10 and the electrolyte solution, wherein the housing 20 has a cylindrical structure, wherein the electrolyte solution comprises a chain ester solvent, wherein the percentage by mass of the chain ester solvent in the electrolyte solution is more than or equal to 25.5 wt.%.

[0220] The percentage by mass of the chain ester solvent is more than or equal to 25.5 wt.%, which results in a relatively high electrical conductivity of the electrolytes, contributing to the improvement of the liquid-phase transfer capability of the active ions, the improvement of the fast charging and discharging capability of the cylindrical battery cell 7, and thus to the improvement of the multiplication performance of the cylindrical battery cell 7.The solvent may cause problems with the generation of decomposition gases during the cyclic charging and discharging of the cylindrical battery cell 7, but the casing 20 of the cylindrical battery cell 7 adopts a cylindrical structure, and the cylindrical structure can distribute the pressure evenly within the cylindrical battery cell 7, so that the casing 20 is subjected to a uniform force at all points, which can effectively increase the pressure resistance of the casing 20, thereby improving the reliability of the use of the cylindrical battery cell 7.

[0221] On the other hand, the electrode assembly 10 is subjected to extrusion and backflow of the electrolyte solution due to the cyclic charging and discharging process. Since the housing 20 has a cylindrical structure, the size of the cylindrical battery cell 7 can be much larger along the axial direction than its size in the radial direction, resulting in a longer electrolyte backflow path in the axial direction and making it difficult for the electrode assembly 10 to be sufficiently infiltrated. Furthermore, the electrolyte solution in the embodiment of the present application contains a chain ester solvent, and the percentage by mass of the chain ester solvent is greater than or equal to 25.5% by weight.-%, so that the viscosity of the electrolyte system is relatively low and it is easier to flow through the electrode assembly 10, which can improve the fast charging and discharging capability of the cylindrical battery cell 7 and thus improve the multiplication performance of the cylindrical battery cell 7;.

[0222] As a result, the embodiments of the present application are able to improve the multiplication performance of the cylindrical battery cell 7 and the reliability of its use in a balanced manner by using a specific electrolyte system in conjunction with the cylindrical housing 20.

[0223] In some embodiments, the percentage by mass of the chain ester solvent in the electrolyte solution is 25.5 wt% to 76.5 wt%, optionally 25.5 wt% to 70 wt%, and further optionally 42.5 wt% to 70 wt%. When the percentage by mass of the chain ester solvent is within the above range, it can further improve the multiplication performance and reliability of the use of battery cell 7, and it can also further improve the cycle performance of battery cell 7.

[0224] For example, the percentage by mass of the chain ester solvent in the electrolyte solution can be 25.5 wt.%, 26 wt.%, 27 wt.%, 28 wt.%, 29 wt.%, 30 wt.%, 32 wt.%, 35 wt.%, 38 wt.%, 40 wt.%, 42 wt.%, 45 wt.%, 48 wt.%, 50 wt.%, 52 wt.%, 55 wt.%, 58 wt.% in the electrolyte, 60 wt.%, 62 wt.%, 65 wt.%, 68 wt.%, 70 wt.%, 72 wt.%, 75 wt.%, 76.5 wt.%, or any value in a range between any two of these values.

[0225] In some embodiments, the chain ester solvent comprises a chain carbonate ester. The chain carboxylic acid ester is able to improve the electrical conductivity of the electrolyte solution, improve the kinetic liquid-phase transfer performance of the electrolyte solution, and further improve the multiplication performance and reliability of the use of the cylindrical battery cell 7.

[0226] In some embodiments, the percentage by mass of the chain carbonate ester in the electrolyte solution is 4 wt% to 70 wt%. Optionally, the percentage by mass of the chain carbonate ester is 4 wt% to 42.5 wt%, or optionally 8.5 wt% to 35 wt%. When the percentage by mass of the chain carbonate ester is in the above range, it is able to improve the electrical conductivity of the electrolyte solution, the liquid-phase kinetic transfer performance of the electrolyte solution, and the multiplication performance and reliability of the use of battery cell 7, and further improve the cycle performance of battery cell 7.

[0227] For example, the percentage by mass of the chain carbonate ester in the electrolyte solution can be 4 wt.%, 4.5 wt.%, 5 wt.%, 8 wt.%, 10 wt.%, 12 wt.%, 15 wt.%, 18 wt.%, 20 wt.%, 22 wt.%, 25 wt.%, 30 wt.%, 35 wt.%, 40 wt.%, 45 wt.%, 50 wt.%, 55 wt.%, 60 wt.%, 65 wt.%, 70 wt.% or any value in a range between any two of these values.

[0228] In some embodiments, the chain carbonate ester comprises a compound represented in formula 1, where in formula IR 11 and R 12 Each independently comprises a C1 to C3 alkyl group or a C1 to C3 haloalkyl group. When the chain carbonate ester consists of the above materials, it can further improve the multiplication performance and reliability of the use of the cylindrical battery cell 7, and it can also further improve the cycle performance of the cylindrical battery cell 7.

[0229] In some embodiments, formula AR includes 11 and R 12 Each independently of each other a C1 to C3 alkyl group or a C1 to C3 fluoroalkyl group.

[0230] Optionally, the chain carbonate ester comprises one or more of the compounds shown in Formula I-1 to Formula I-6,

[0231] Optionally, the chain carbonate ester comprises a compound represented in formula I-1,

[0232] For example, the chain carbonate ester comprises a compound represented in formula I-1, wherein the percentage by mass of the compound represented in formula 1-1 in the electrolyte solution is 4 wt.% to 42.5 wt.%, optionally 8.5 wt.% to 35 wt.%;

[0233] In some embodiments, the chain ester solvent further comprises a chain carboxylic acid ester. When used in combination, the chain carboxylic acid ester and the chain carbonate ester are able to improve the electrical conductivity of the electrolyte solution, enhance the liquid-phase transfer kinetics of the electrolyte solution, and further improve the multiplication performance and reliability of the cylindrical battery cell 7, as well as the cycle performance of the cylindrical battery cell 7. Of course, the chain carboxylic acid esters can also be used as a standalone solvent system.

[0234] In some embodiments, the percentage by mass of the chain carboxylic acid ester in the electrolyte solution is 4 wt% to 70 wt%, optionally 8.5 wt% to 60 wt%, and further optionally 20 wt% to 55 wt%. When the percentage by mass of the chain carboxylic acid ester in the electrolyte solution is in the above range, it is able to improve the electrical conductivity of the electrolyte solution, improve the liquid-phase transfer kinetics of the electrolyte solution, and further improve the multiplication performance and reliability of the use of battery cell 7.

[0235] For example, the percentage by mass of the chain carboxylic acid ester in the electrolyte solution is 4 wt%, 4.5 wt%, 5 wt%, 8 wt%, 8.5 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt% or any value in a range between any two of these values.

[0236] In some embodiments, the chain carboxylic acid ester comprises a compound represented in formula II, where in Formula II R 21 comprises a hydrogen atom, a halogen atom, a C1 to C3 alkyl group or a C1 to C3 haloalkyl group; R 22 comprises a C1 to C3 alkyl group or a C1 to C3 haloalkyl group.

[0237] In some embodiments, R comprises 21 a hydrogen atom, a fluorine atom, a C1 to C3 alkyl group or a C1 to C3 fluoroalkyl group.

[0238] In some embodiments, R comprises 22 a C1 to C3 alkyl group or a C1 to C3 fluoroalkyl group.

[0239] For example, the chain carboxylic acid ester comprises one or more of the compounds shown in formula II-1 to formula II-6,

[0240] Optionally, for example, the chain carboxylic acid ester comprises one or more of the compounds shown in Formula II-1 to Formula II-6,

[0241] The chain carboxylic acid ester can include a variety of options,

[0242] For example, the chain carboxylic acid ester comprises the compound shown in formula 11-2, wherein the percentage mass fraction of the compound shown in formula II-2 in the electrolyte solution is 20 wt.% to 55 wt.%.

[0243] For the other example, the chain carboxylic acid ester comprises the compound shown in formula II-3, wherein the percentage by mass of the compound shown in formula II-3 in the electrolyte solution is 20 wt.% to 55 wt.%.

[0244] For a further example, the chain carboxylic acid ester comprises the compounds shown in formula 11-2 and in formula II-3, wherein the percentage by mass of the compounds shown in formula II-2 and in formula II-3 in the electrolyte solution is 20 wt.% to 55 wt.%;

[0245] For example, the chain ester solvent of the electrolyte solution may further comprise a compound shown in Formula I-1 and in Formula II-2, the percentage by mass of the chain ester solvent in the electrolyte solution being 25.5 wt.% to 76.5 wt.%, optionally 25.5 wt.% to 70 wt.%, optionally 42.5 wt.% to 70 wt.%. For example, the percentage by mass of the compound shown in Formula I-1 in the electrolyte solution is 8.5 wt.% to 35 wt.%, and the percentage by mass of the compound shown in Formula II-2 is 20 wt.% to 55 wt.%.

[0246] For example, the chain ester solvent of the electrolyte solution may further comprise a compound shown in Formula I-1 and in Formula II-3, the percentage by mass of the chain ester solvent in the electrolyte solution being 25.5 wt% to 76.5 wt%, optionally 25.5 wt% to 70 wt%, optionally 42.5 wt% to 70 wt%. For example, the percentage by mass of the compound shown in Formula I-1 in the electrolyte solution is 8.5 wt% to 35 wt%, and the percentage by mass of the compound shown in Formula II-3 in the electrolyte solution is 20 wt% to 55 wt%.

[0247] For example, the chain ester solvent of the electrolyte solution may further comprise a compound shown in Formula I-1, Formula II-2, and Formula II-3, the percentage by mass of the chain ester solvent in the electrolyte solution being 25.5 wt.% to 76.5 wt.%, optionally 25.5 wt.% to 70 wt.%, optionally 42.5 wt.% to 70 wt.%. For example, the percentage by mass of the compound shown in Formula I-1 in the electrolyte solution is 8.5 wt.% to 35 wt.%, the percentage by mass of the compound shown in Formula II-2 in the electrolyte solution is 8.5 wt.% to 35 wt.%, and the percentage by mass of the compound shown in Formula II-3 in the electrolyte solution is 8.5 wt.% to 35 wt.%.

[0248] The housing 20 has a cylindrical structure, and the housing 20 comprises a housing body 21, the housing body 21 being able to have a cylindrical structure corresponding to the shape of the electrode assembly 10, which is also a cylindrical structure. The material of the housing 20 can be different; for example, the base material of the housing 20 includes, but is not limited to, copper, iron, aluminum, steel, aluminum alloy, and the like. Optionally, the base material of the housing 20 includes steel, for example, stainless steel. For example, the base material of the housing body 21 includes steel, for example, stainless steel. The shape of the end cap 22 can be adapted to the shape of the housing body 21 so that it fits into the housing body 21. The base material of the end cap 22 and the base material of the housing body 21 can be the same or different. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (e.g.,The end cap 22 can be manufactured from materials such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc., so that it is less likely to deform when subjected to extrusion and collision, thus enabling the cylindrical battery cell 7 to have higher structural strength and improved reliability. Optionally, the base material of the end cap 22 can include steel, such as stainless steel. In the embodiments of the present application, the base material is the predominant material.

[0249] In some embodiments, the housing 20 comprises a housing body 21 and an end cap 22, wherein the housing body 21 comprises a side wall 212 and an end wall 211 connected to the side wall 212, wherein the housing body 21 is provided with an opening, wherein the end cap 22 is connected to the side wall 212 and covers the opening, and wherein the end cap 22 and the end wall 211 are opposite each other along an axial direction of the housing 20.

[0250] In some embodiments, the side wall 212 and the end wall 211 form a single-piece molded structure.

[0251] In some embodiments, the base material of the side wall 212 comprises steel, with the thickness of the side wall 212 being 0.30 mm to 1.2 mm, optionally 0.30 mm to 0.55 mm. When the thickness of the side wall 212 is within the above range, the side wall 212 has higher strength and greater compressive strength, which effectively reduces the risk of deformation of the side wall 212, decreases the risk of bulging of the cylindrical battery cell 7, and thus improves the reliability of the use of the cylindrical battery cell 7.

[0252] For example, the thickness of the side wall 212 can be 0.30 mm, 0.31 mm, 0.32 mm, 0.35 mm, 0.38 mm, 0.4 mm, 0.45 mm, 0.48 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.5 mm or any value in a range between two of these values.

[0253] In some embodiments, the base material of the side wall 212 comprises steel. When the thickness of the side wall 212 is 0.30 mm to 1.2 mm, the percentage by mass of the chain ester solvent is 25.5 wt.% to 76.5 wt.%. While the percentage by mass of the chain ester solvent in the above range can improve the multiplication performance of the cylindrical battery cell 7, it also generates a certain amount of gas within the cylindrical battery cell 7, which poses a risk of bulging.If the thickness of the housing 20 is in the above range, the housing 20 has a higher strength and greater pressure resistance, which effectively reduces the risk of deformation of the housing 20, decreases the risk of bulging of the cylindrical battery cell 7 and thus improves the reliability of the use of the cylindrical battery cell 7, and the cycle performance of the cylindrical battery cell 7 can also be improved.

[0254] In some embodiments, the base material of the side wall 212 comprises steel. When the thickness of the side wall 212 is 0.30 mm to 0.55 mm, the percentage by mass of the chain ester solvent is 25.5 wt.% to 70 wt.%. The thickness of the casing 20 and the percentage by mass of the chain ester solvent are matched as described above to increase the multiplication performance and reliability of the use of the cylindrical battery cell 7 in a balanced manner and to improve the cycle performance of the cylindrical battery cell 7.

[0255] Fig. Figure 6 shows a sectional view of the structure of a cylindrical battery cell 7 according to some embodiments of the present application, and Fig. Figure 7 shows a schematic enlarged representation of the cylindrical battery cell 7 of A in Fig. 6.

[0256] As in Fig. 6 and Fig.Figure 7 shows that in some embodiments the housing 20 comprises a housing body 21 and an end cap 22, wherein the housing body 21 is provided with an opening, wherein the end cap 22 is connected to the housing body 21 and covers the opening, and wherein the end cap 22 is provided with a pressure relief mechanism 220.

[0257] If a short circuit, overcharging, or similar event occurs, the electrolyte solution and the active materials react, releasing gases and heat. The pressure relief mechanism 220 is configured to deform when the internal pressure or temperature of the housing 20 reaches a threshold, allowing the interior of the housing 20 to be connected to the exterior space to release the pressure or temperature within the housing 20. Deformations of the pressure relief mechanism 220 include, but are not limited to, breakage, melting, and the like. The threshold determination varies depending on the design requirements. The threshold may depend on the material of one or more of the cathode foils, the anode foils, the electrolyte solution, and the separator element in the cylindrical battery cell 7.

[0258] In the embodiments of the present application, the deformation of the pressure relief mechanism 220 can be triggered by the internal pressure of the housing 20, by the internal temperature of the housing 20, or by a combination of the internal pressure and the internal temperature of the housing 20.

[0259] For example, if the gas continues to accumulate in the housing 20, the internal pressure of the housing 20 can reach or even exceed a pressure threshold. When the internal pressure of the housing 20 reaches the pressure threshold, the pressure relief mechanism 220 deforms under the influence of the internal pressure to connect the interior of the housing 20 to the outside, and the gas inside the housing 20 can be released, thereby reducing the risk of explosion of the cylindrical battery cell 7.

[0260] For example, if the electrolyte solution and the active material react and rapidly release heat, an increase in the internal temperature of the housing 20 is triggered, and the temperature increase also causes an increase in the internal pressure of the housing 20. When the internal temperature of the housing 20 reaches the threshold, the pressure relief mechanism 220 deforms under the influence of the pressure and temperature to connect the interior of the housing 20 to the outside space, and the gas inside the housing 20 can be released, thereby reducing the risk of explosion of the cylindrical battery cell 7.

[0261] In the event that the internal pressure or temperature of the housing 20 reaches a threshold value, embodiments of the present application can utilize the deformation of the pressure relief mechanism 220 to connect the interior of the housing 20 with the exterior space, thereby venting the internal gas and pressure of the housing 20 and reducing the risk of explosion of the cylindrical battery cell 7.

[0262] In some embodiments, the end cap 22 is provided with a concave section 221, wherein a bottom wall of the concave section 221 is the weak section 222. The weak section 222 is configured to rupture when the internal pressure of the cylindrical battery cell 7 reaches a threshold value in order to release the internal pressure.

[0263] When the weak section 222 breaks, a channel is formed that can be used to release the internal pressure. Upon breaking of the weak section 222, the internal gases of the cylindrical battery cell 7 are vented outwards from the broken section, allowing pressure relief of the cylindrical battery cell 7 at a controlled pressure, thus preventing a potentially more serious accident.

[0264] In some embodiments, the base material of the weak section 222 comprises steel, and the thickness of the weak section 222 is 0.01 mm to 0.3 mm, optionally 0.05 mm to 0.2 mm. When the thickness of the weak section 222 is in the above range, the weak section 222 has higher strength and greater compressive strength, which can effectively improve the compressive strength of the cylindrical battery cell 7 and the reliability of its use.

[0265] For example, the thickness of the weak section 222 can be 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm or any value in a range between two of these values.

[0266] In some embodiments, the base material of the weakened section 222 comprises steel. When the thickness of the weakened section 222 is 0.01 mm to 0.3 mm, the percentage by mass of the chain ester solvent is 25.5 wt.% to 76.5 wt.%. While a percentage by mass of the chain ester solvent in the above range can improve the multiplication performance of the cylindrical battery cell 7, it also generates a certain amount of gas within the cylindrical battery cell 7, creating a risk of bulging. In embodiments of the present application, when the thickness of the weakened section 222 is in the above range, the weakened section 222 exhibits higher strength, greater pressure resistance, and effectively improves the pressure resistance of the cylindrical battery cell 7, thereby enhancing the reliability of its use.

[0267] In some embodiments, the base material of the weak section 222 comprises steel. When the thickness of the weak section 222 is 0.05 mm to 0.2 mm, the percentage by mass of the chain ester solvent is 25.5 wt.% to 70 wt.%. The thickness of the casing 20 and the percentage by mass of the chain ester solvent are matched as described above to increase the multiplication performance and reliability of the cylindrical battery cell 7 in a balanced manner.

[0268] In some embodiments, the organic solvent may also comprise, but is not limited to, at least one of the following cyclic carbonates: butyl carbonate (BC), fluoroethylene carbonate (FEC), 1,4-butyrolactone (GBL), cyclobutyl sulfone (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE). Optionally, the organic solvent may also contain a cyclic carbonate. The cyclic carbonate may, for example, comprise at least one of the following compounds: ethylene carbonate (EC), propylene carbonate (PC), or fluorinated ethylene carbonate (FEC).

[0269] The qualitative characterization and quantitative characterization of each substance or element in the electrolyte solution in the present application can be tested using suitable equipment and methods known to those skilled in the art. The relevant test procedure may refer to domestic and foreign testing standards, domestic and foreign company standards, etc. Those skilled in the art may also adaptively modify certain test steps / instrument parameters, etc., with regard to accuracy, in order to obtain a more accurate test result. A test procedure may be used qualitatively or quantitatively, and several test procedures may be used together for a qualitative or quantitative determination.

[0270] In the embodiments of the present application, the type and content of the inorganic component / lithium salt concentration in the electrolyte solution are known in the art and can be detected using equipment and methods known in the art; for example, the inorganic component / lithium salt concentration in the electrolyte solution can be analyzed qualitatively or quantitatively by means of ion chromatography with reference to the standard JY / T020-1996 "General principles of ion chromatography analysis methods".In the embodiments of the present application, a freshly prepared electrolyte solution can be taken as a sample, or a discharged battery (which has been discharged to a lower limit voltage so that the state of charge of the battery is approximately 0% SOC) can be disassembled in reverse, and the free electrolyte solution obtained from the battery can be taken as a sample and tested using the ion chromatographic analysis method.

[0271] In the embodiments of the present application, the nature and concentration of the organic components in the electrolyte solution are known in the art and can be detected using equipment and methods known in the art. For example, the organic components in the electrolyte solution can be qualitatively and quantitatively analyzed by gas chromatography with reference to GB / T9722-2006 "General principles for the gas chromatography of chemical reagents". In the embodiments of the present application, a freshly prepared electrolyte solution can be taken as a sample, or a discharged battery (which has been discharged to a lower limit voltage so that the state of charge of the battery is approximately 0% SOC) can be disassembled in the reverse manner, and the free electrolyte solution obtained from the battery can be taken as a sample and tested using the ion chromatographic method.

[0272] In the embodiments of the present application, the thickness of the weak section 222 has a meaning known in the art and can be determined using devices and methods known in the art, such as by testing the thickness with a micrometer.

[0273] In the embodiments of the present application, the thickness of the film layer has a meaning known in the art and can be tested using devices and methods known in the art, e.g. by cutting the housing 20, checking the thickness of the film layer at different locations with an X-ray thickness gauge and determining the average value as the thickness of the film layer.

[0274] In the embodiments of the present application, the type and proportion of elements in the film layer are known in the prior art and can be tested using equipment and methods known in the prior art. For example, an energy spectrometer and a scanning electron microscope are used to test the type and proportion of elements on the surface of the film layer, and the proportion of the type and proportion of elements on the surface of the film layer is essentially the same as the proportion of the type and proportion of elements in the film layer, and the type and proportion of elements in the film layer are characterized by testing the proportion of the type and proportion of elements on the surface of the film layer. Example of implementation

[0275] The following embodiments describe in more detail what is disclosed in the embodiments of the present application, and these embodiments serve only for illustration, since various modifications and variations within the scope of disclosure of the embodiments of the present application will be obvious to the person skilled in the art. Unless otherwise stated, all parts, percentages, and ratios given in the following embodiments are based on mass counts, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the equipment used in the embodiments is commercially available. Example 11. Production of the cathode foil:

[0276] The cathode foil comprises a cathode collector and a cathode film layer. The cathode film layer is located on both sides of the cathode collector, which is an aluminum foil. The cathode film layer is a cathode slurry (whose solvent is N-methylpyrrolidone, NMP) uniformly coated onto the surface of the aluminum foil of the cathode collector. The film layer is formed after drying and cold pressing and comprises an active cathode material, a conductive acetylene black, and a polyvinylidene fluoride binder in a mass ratio of 96.5:2:1.5.

[0277] The active cathode material comprises a compound with the molecular formula LiNi 0.9 Co 0.05 Mn 0.05 O2(Ni90). 2. Production of the anode foil:

[0278] The anode foil comprises an anode collector and an anode film layer. The anode film layer is located on both sides of the anode collector. The anode collector is a copper foil, and the anode film layer is an anode slurry (whose solvent is deionized water) uniformly coated onto the surface of the copper foil of the anode collector. The film layer is formed after drying and cold pressing and comprises an active anode material, a styrene-butadiene rubber (SBR) binder, a sodium carboxymethylcellulose (CMC-Na) thickener, and a conductive acetylene black in a mass ratio of 96.2:1.8:1.2:0.8.

[0279] The active anode material comprises synthetic graphite and silicon-based materials (especially silicon-carbon compounds), and the silicon content in the anode film layer is 5%. 3. Separating film

[0280] The separation membrane is a polypropylene (PP) film layer. 4. Preparation of the electrolyte solution

[0281] The electrolyte solution comprises an organic solvent and a lithium salt. The organic solvent includes a chain ester solvent and a cyclic ester solvent (vinyl carbonate). The chain ester solvent comprises chain carbonate esters (dimethyl carbonate, DMC) and chain carboxylic acid esters (methyl acetate and ethyl acetate in a mass ratio of 1:1). The mass ratio of chain carbonate, chain carboxylic acid esters, and vinyl carbonate is 3:4:3. The lithium salt comprises lithium hexafluorophosphate (LiPF6) and lithium bis(trifluorosulfonyl)imide (LiFSI).After mixing dimethyl carbonate DMC, methyl acetate, ethyl acetate and vinyl carbonate according to the above mass ratio, the sufficiently dried lithium salt was dissolved in the mixed organic solvent to formulate the electrolyte solution, wherein the molar concentration of lithium hexafluorophosphate LiPF6 is 0.6 mol / l and the molar concentration of lithium bifluorosulfonimide LiFSI is 0.4 mol / l. 5. Production of the cylindrical battery cell

[0282] Stacking the above cathode foil, separator film, and anode foil in sequence, such that the separator film is located between the cathode foil and the anode foil, and winding the cathode foil, separator film, and anode foil to obtain the electrode assembly; the electrode assembly is arranged in a housing with a cylindrical structure, dried, and injected with electrolyte solution, and after vacuum encapsulation, storage, forming, shaping, and other processes, a cylindrical battery cell is obtained, wherein the housing comprises a housing body and an end cap, the housing body comprising a side wall and an end wall formed in one piece, the side wall being arranged around the electrode assembly, the end cap and the end wall being opposite each other along the axial direction of the housing, the side wall comprising a housing base body and a film layer.wherein the film layer is arranged on two surfaces of the housing base body. The housing base body is made of stainless steel, the film layer has a thickness of 3 µm, and the film layer consists of 90 wt.% nickel, 2 wt.% iron, and 5 wt.% carbon. Comparative example 1

[0283] A cylindrical battery cell is manufactured according to a similar process to that in embodiment 1, and in contrast to embodiment 1, the lithium salt comprises 0.9 mol / L lithium hexafluorophosphate LiPF6, and the side wall does not comprise a film layer. Exemplary embodiment 2-1 to Exemplary embodiment 2-11

[0284] A cylindrical battery cell is manufactured according to a similar process as in embodiment 1, and in contrast to embodiment 1, the composition of the lithium salt is adapted. Exemplary embodiment 3-1 and Exemplary embodiment 3-2

[0285] A cylindrical battery cell is manufactured according to a similar process as in embodiment 1, and in contrast to embodiment 1, the type of sulfonamide salt in the lithium salt is adapted. Performance test 1. Cycle performance test of the battery cell

[0286] At 45 °C, the cylindrical battery cells produced in each embodiment and comparative example are charged at a constant current with a multiplication rate of 0.5 C up to a charging cut-off voltage of 4.25 V, then charged at a constant voltage to a current of less than or equal to 0.05 C and stored for 5 minutes. They are then discharged at a constant current with a multiplication rate of 0.33 C down to a discharge cut-off voltage of 2.5 V and stored for another 5 minutes, constituting one charge-discharge cycle. After the aforementioned charge / discharge cycle test on the battery cell, the battery cell's capacity retention rate is calculated after 800 cycles. 2. Testing gas generation during battery storage

[0287] At 25 °C, the cylindrical battery cells produced in each embodiment and comparative example are charged at a constant current with a multiplication rate of 0.5 C up to 4.25 V, and then charged at a constant voltage to a current of ≤0.05 C, and then the battery is placed at 60 °C for storage for 100 days, and the internal pressure of the battery is determined using an external pressure gauge (MPa). 3. Internal resistance test of the battery cell

[0288] At 45 °C, the cylindrical battery cells produced in each embodiment and comparative example are charged at a constant current with a multiplication rate of 1 C up to 4.25 V, and then charged at a constant voltage to a current of less than or equal to 0.05 C, and then discharged at 1 C for 30 min, and the capacity of the battery cell is set to a 50% state of charge (SOC).

[0289] The positive and negative pins of the TH2523A AC internal resistance meter were used to contact the cathode and anode of the battery cell, and the internal resistance value (mΩ) of the battery cell was read using the internal resistance meter. Test result

[0290] The test results are listed in Table 1. Table 1 Positions electrolyte solution Battery power Capacity maintenance rate / % Internal pressure / MPa Internal resistance / m Ω Molar concentration of lithium hexafluorophosphate M1 / (mol / L) Sulfonamide salt M1+M2 / (mol / L) M2 / M1 material Molar concentrationM2 / (mol / L) Comparative example 1 0,9 / / 0,9 / 71,2 0,288 18,3 Example 1 0,6 Formula A-1 0,4 1,0 0,67 80,0 0,250 5,0 Example 2-1 0,2 Formula A-1 0,4 0,6 2,00 82,4 0,242 8,9 Example 2-2 0,3 Formula A-1 0,4 0,7 1,33 80,5 0,245 5,8 Example 2-3 0,7 Formula A-1 0,4 1,1 0,57 77,6 0,252 5,1 Example 2-4 0,8 Formula A-1 0,4 1,2 0,50 75,3 0,261 4,5 Example 2-5 0,6 Formula A-1 0,2 0,8 0,33 75,4 0,258 8,9 Example 2-6 0,6 Formula A-1 0,3 0,9 0,50 78,6 0,251 5,8 Example 2-7 0,6 Formula A-1 0,6 1,2 1,00 79,8 0,246 5,1 Example 2-8 0,6 Formula A-1 0,9 1,5 1,50 82,5 0,244 4,5 Example 2-9 0,9 Formula A-1 0,2 1,1 0,22 74,5 0,259 6,5 Example 2-10 0,9 / / 0,9 / 73,0 0,265 13,0 Example 2-11 1,2 / / 1,2 / 74,0 0,286 10,0 Example 3-1 0,6 Formula A-2 0,4 1,0 0,67 78,6 0,254 6,8 Example 3-2 0,6 Formula A-3 0,4 1,0 0,67 77,5 0,258 7,3

[0291] In Table 1: Formula A-1 represents a bis(trifluorosulfonyl)imide ion, and the corresponding cation is a lithium ion. Formula A-2 represents a bis(trifluoromethanesulfonyl)imide ion, and the corresponding cation is a lithium ion, and Formula A-3 represents a (fluorosulfonyl)(trifluoromethanesulfonyl)imide ion, and the corresponding cation is a lithium ion.

[0292] As can be seen from Table 1:

[0293] The housing in Comparative Example 1 is made of stainless steel, which is readily corroded by lithium hexafluorophosphate. In comparison to Comparative Example 1, the embodiment of the present application, by applying a nickel-containing film layer to the surface of the housing, can effectively improve the corrosion resistance of the housing, reduce the risk of corrosion of the housing by the hydrofluoric acid produced by the decomposition of the lithium hexafluorophosphate, thus contributing to an improvement in the cycle performance of the cylindrical battery cell, and can also reduce the internal pressure of the cylindrical battery cell, decrease the amount of gas generation, and improve the reliability of the use of the cylindrical battery cell.

[0294] By adjusting the composition of the lithium salt, embodiments 2-1 to 2-11 can further improve the cycle performance of the cylindrical battery cell, reduce the internal pressure of the cylindrical battery cell, decrease the amount of gas generation, improve the reliability of the cylindrical battery cell, improve the ion-liquid-phase transfer capability of the electrolyte system, reduce the electrical resistance, and improve the multiplication performance. By adjusting the composition of the sulfonamide salt, embodiments 3-1 and 3-2 can further improve the cycle performance of the cylindrical battery cell, reduce the internal pressure of the cylindrical battery cell, decrease the amount of gas generation, improve the reliability of the cylindrical battery cell, improve the ion-liquid-phase transfer capability of the electrolyte system, reduce the electrical resistance, and improve the multiplication performance. Example 4

[0295] A cylindrical battery cell is manufactured according to a similar process as in embodiment 1, and in contrast to embodiment 1, the thickness of the film layer in the side wall of the housing is adjusted. Example 5

[0296] A cylindrical battery cell is manufactured according to a similar process as in embodiment 1, and in contrast to embodiment 1, the composition of the film layer in the side wall of the housing is adapted.

[0297] The test results are listed in Table 2. Table 2 Positions Film layer in the side wall of the housing Battery power Percentage of Ni by weight % Percentage of iron / weight by mass % Percentage of C by mass (% of weight) Thickness / µm Capacity maintenance rate / % Internal pressure / MPa Internal resistance / mΩ Example 4 90 2 5 2,0 80,4 0,253 5,5 Example 5 80 8 12 3,0 80,3 0,252 5,4

[0298] As can be seen from Table 2, the electrolyte system in the embodiments of the present application is applicable to metal housings with different film thicknesses, e.g. 1.5 µm to 6.0 µm, optionally 2.0 µm to 4.0 µm; if the film layer meets the above-mentioned ranges, the battery has excellent cycle performance and reliability of use.

[0299] The electrolyte system in the embodiments of the present application is applicable to metal housings with film layers of varying nickel content, such as 70 wt.% to 100 wt.%, optionally 80 wt.% to 95 wt.%; if the percentage mass fraction of the nickel element meets the above range, the battery has excellent cycle performance and reliability of use. Exemplary embodiment 6-1 and Exemplary embodiment 6-2

[0300] A cylindrical battery cell is manufactured according to a similar process as in embodiment 1, and in contrast to embodiment 1, the percentage mass fraction of the silicon element in the anode film layer is adjusted.

[0301] The test results are listed in Table 3. Table 3 Positions Anode film layer Battery power Percentage of Si by mass / wt% Capacity maintenance rate % Internal pressure / MPa Internal resistance / mΩ Example 6-1 3 85,0 0,245 4 Example 6-2 20 75,0 0,270 10

[0302] As can be seen from Table 3, by adjusting the percentage mass fraction of the silicon element in the anode film layer, embodiments 6-1 to 6-2 can further improve the cycle performance of the cylindrical battery cell and reduce the internal pressure of the cylindrical battery cell, decrease the amount of gas generation and improve the reliability of the use of the cylindrical battery cell.

[0303] Although illustrative embodiments have been demonstrated and described, those skilled in the art should understand that the above embodiments are not to be construed as limiting the present application and that changes, replacements and modifications to the embodiments may be made without departing from the spirit, principles and scope of the present application. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 202410543473

[0001]

Claims

[1] Cylindrical battery cell comprising an electrolyte solution, an electrode assembly and a housing, wherein the housing accommodates the electrolyte solution and the electrode assembly, wherein: the electrolyte solution comprises an electrolyte salt, wherein the electrolyte salt comprises a hexafluorophosphate; the housing comprises a housing base body and a film layer, wherein the film layer is provided at least on one surface of the housing base body facing the electrode assembly, and wherein a base element of the film layer is a nickel element. [2] Cylindrical battery cell according to claim 1, wherein the molar concentration of the hexafluorophosphate is less than or equal to 1.2 mol / L. [3] Cylindrical battery cell according to claim 2, wherein the molar concentration of the hexafluorophosphate is less than or equal to 0.9 mol / L. [4] Cylindrical battery cell according to claim 3, wherein the molar concentration of the hexafluorophosphate is 0.2 mol / L to 0.8 mol / L. [5] Cylindrical battery cell according to claim 4, wherein the molar concentration of the hexafluorophosphate is 0.3mol / L to 0.7mol / L. [6] Cylindrical battery cell according to any one of claims 1 to 5, wherein the thickness of the film layer is 1.5 µm to 6.0 µm. [7] Cylindrical battery cell according to claim 6, wherein the thickness of the film layer is 2.0 µm to 4.0 µm. [8] Cylindrical battery cell according to one of claims 1 to 7, wherein a percentage by mass of the nickel element in the film layer is 70 wt.% to 100 wt.%. [9] Cylindrical battery cell according to claim 8, wherein the percentage by mass of the nickel element in the film layer is 80 wt.% to 95 wt.%. [10] Cylindrical battery cell according to any one of claims 1 to 9, wherein the film layer further comprises an iron element, wherein the percentage by mass of the iron element in the film layer is 0.1 wt.% to 10 wt.%, and / or wherein The film layer further comprises a carbon element, wherein the percentage mass fraction of the carbon element in the film layer is 0.1 wt.% to 15 wt.%. [11] Cylindrical battery cell according to claim 10, wherein the percentage by mass of the iron element in the film layer is 1 wt.% to 5 wt.%. [12] Cylindrical battery cell according to claim 10 or 11, wherein the percentage mass fraction of the carbon element in the film layer is 4 wt.% to 12 wt.%. [13] Cylindrical battery cell according to one of claims 1 to 12, wherein the electrolyte salt comprises a sulfonamide salt, wherein the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate is 0.06 to 6. [14] Cylindrical battery cell according to claim 13, wherein the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate is 0.2 to 2. [15] Cylindrical battery cell according to claim 14, wherein the ratio of the molar concentration of the sulfonamide salt to the molar concentration of the hexafluorophosphate is 0.3 to 1.

5. [16] Cylindrical battery cell according to one of claims 13 to 15, wherein the molar concentration of the electrolyte salt is 0.5 mol / L to 2 mol / L. [17] Cylindrical battery cell according to claim 16, wherein the molar concentration of the electrolyte salt is 0.6 mol / L to 1.5 mol / L. [18] Cylindrical battery cell according to any one of claims 13 to 17, wherein the sulfonamide salt comprises an anion represented in formula A, where in formula A R1 and R2 each independently comprise a halogen atom or a C1 to C6 haloalkyl group. [19] Cylindrical battery cell according to claim 18, wherein the halogen atom comprises a fluorine atom; and / or wherein the C1 to C6 halogenalkyl group comprises a C1 to C6 fluoroalkyl group. [20] Cylindrical battery cell according to claim 18 or 19, wherein R1 and R2 each independently comprise a fluorine atom or a C1 to C3 fluoroalkyl group. [21] Cylindrical battery cell according to one of claims 18 to 20, wherein the anion shown in formula A comprises one or more of the anions shown in formula A-1 to formula A-5, [22] Cylindrical battery cell according to claim 21, wherein the anion shown in formula A comprises one or more of the anions shown in formula A-1 to formula A-2, [23] Cylindrical battery cell according to one of claims 1 to 22, wherein a base material of the housing base body is made of steel. [24] Cylindrical battery cell according to one of claims 1 to 23, wherein the electrode assembly comprises an anode foil, wherein the anode foil comprises an anode collector and an anode film layer provided on at least one side of the anode collector and containing an active anode material, wherein the active anode material comprises a silicon element, [25] Cylindrical battery cell according to claim 24, wherein the percentage by mass of the silicon element in the anode film layer is 1 wt.% to 32 wt.%. [26] Cylindrical battery cell according to any one of claims 1 to 25, wherein the electrolyte solution comprises a chain ester solvent, wherein the percentage by mass of the chain ester solvent in the electrolyte solution is more than or equal to 25.5 wt.%. [27] Cylindrical battery cell according to claim 26, wherein the percentage by mass of the chain ester solvent in the electrolyte solution is 25.5 wt.% to 76.5 wt.%. [28] Cylindrical battery cell according to claim 26 or 27, wherein the chain ester solvent comprises a chain carbonate, wherein the percentage by mass of the chain carbonate in the electrolyte solution is 4 wt.% to 70 wt.%. [29] Cylindrical battery cell according to claim 28, wherein the chain carbonate comprises a compound represented in formula I, wherein in formula IR 11 and R 12 each independently comprise a C1 to C3 alkyl group or a C1 to C3 haloalkyl group. [30] Cylindrical battery cell according to claim 29, wherein R 11 and R 12 each independently comprise a C1 to C3 alkyl group or a C1 to C3 haloalkyl group. [31] Cylindrical battery cell according to claim 29 or 30, wherein the chain carbonate comprises one or more of the compounds shown in Formula I-1 to Formula I-6, [32] Cylindrical battery cell according to claim 31, wherein the chain carbonate comprises a compound as illustrated in formula 1-1, [33] Cylindrical battery cell according to one of claims 26 to 32, wherein the chain ester solvent further comprises a chain carboxylic acid ester, wherein the percentage by mass of the chain carboxylic acid ester in the electrolyte solution is 4 wt.% to 70 wt.%. [34] Cylindrical battery cell according to claim 33, wherein the percentage by mass of the chain carboxylic acid ester in the electrolyte solution is 8.5 wt.% to 60 wt.%. [35] Cylindrical battery cell according to claim 33 or 34, wherein the chain carboxylic acid ester comprises a compound represented in formula II, where in Formula II R 21 comprises a hydrogen atom, a halogen atom, a C1 to C3 alkyl group or a C1 to C3 haloalkyl group; R 22 comprises a C1 to C3 alkyl group or a C1 to C3 haloalkyl group. [36] Cylindrical battery cell according to claim 35, wherein: R 21 comprising a hydrogen atom, a fluorine atom, a C1 to C3 alkyl group or a C1 to C3 fluoroalkyl group; and / or wherein R 22 comprises a C1 to C3 alkyl group or a C1 to C3 fluoroalkyl group. [37] Cylindrical battery cell according to claim 35 or 36, wherein the chain carboxylic acid ester comprises one or more of the compounds shown in formula II-1 to formula II-6, [38] Cylindrical battery cell according to claim 37, wherein: the chain carboxylic acid ester comprises one or more of the compounds shown in formula II-2 and in formula II-3. [39] Cylindrical battery cell according to claim 38, wherein the chain carbonate comprises a compound represented in formula I-1, wherein the percentage by mass of the compound represented in formula I-1 in the electrolyte solution is 8.5 wt.% to 35 wt.%; wherein the chain carboxylic acid ester comprises the compounds shown in formula II-2 and in formula 11-3, wherein the percent mass fraction of the compounds shown in formula 11-2 and in formula II-3 in the electrolyte solution is 20 wt.% to 55 wt.%; [40] Cylindrical battery cell according to any one of claims 1 to 39, wherein the housing comprises a housing body and an end cap, wherein the housing body comprises a side wall and an end wall connected to the side wall, wherein the housing body has an opening, wherein the end cap is connected to the side wall and covers the opening, and wherein the end cap and the end wall are opposite each other along an axial direction of the cylindrical battery cell. [41] Cylindrical battery cell according to claim 40, wherein the base material of the side wall is made of steel, wherein the thickness of the side wall is 0.30 mm to 1.2 mm. [42] Cylindrical battery cell according to claim 40 or 41, wherein the side wall and the end wall form a one-piece molded structure. [43] Cylindrical battery cell according to one of claims 40 to 42, wherein the end cap is provided with a pressure relief mechanism. [44] Cylindrical battery cell according to claim 43, wherein the pressure relief mechanism comprises a weak section, wherein the base material of the weak section comprises steel, wherein the thickness of the weak section is 0.01 mm to 0.3 mm. [45] Cylindrical battery cell according to claim 44, wherein the end cap is provided with a concave section, wherein a bottom wall of the concave section is the weak section. [46] Cylindrical battery cell according to one of claims 40 to 45, wherein the cylindrical battery cell is further provided with an electrode connection provided at the end wall; wherein the cylindrical battery cell comprises an electrode assembly which is received in the housing body, wherein the electrode assembly comprises a first electrode tab and a second electrode tab with opposite polarity, wherein the first electrode tab is electrically connected to the end wall, while the second electrode tab is electrically connected to the electrode connection. [47] Cylindrical battery cell according to any one of claims 1 to 46, wherein the size of the housing along the axial direction of the cylindrical battery cell is 1.3 to 2.5 times the size of the housing along a radial direction of the cylindrical battery cell. [48] ​​Cylindrical battery cell according to any one of claims 1 to 47, wherein the size of the housing along the axial direction of the cylindrical battery cell is 50 mm to 150 mm; and / or wherein the size of the housing along the radial direction of the cylindrical battery cell is 40 mm to 80 mm. [49] Battery comprising a cylindrical battery cell according to any one of claims 1 to 48. [50] Power consumption device comprising a battery according to claim 49.

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