Battery cell, battery, and electric device

Abstract

A battery cell, a battery, and an electric device. The battery cell comprises an electrode assembly; the electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a separator located between the positive electrode sheet and the negative electrode sheet; the negative electrode sheet comprises a negative electrode composite current collector and a negative electrode active layer located on at least one surface of the negative electrode composite current collector; and the negative electrode composite current collector comprises a polymer material supporting layer and a conductive layer located on the surface of the polymer material supporting layer.

Description

Battery cells, batteries, and electrical devices Technical Field

[0001] The present application relates to the field of batteries, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] In recent years, lithium-ion batteries and other batteries have been widely used in energy storage systems such as hydropower, thermal, wind, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, and other fields. As the scope of use of lithium-ion batteries and other batteries continues to expand, correspondingly higher requirements are placed on battery performance. During battery use, the expansion of the active layer in the negative electrode sheet can squeeze the negative electrode current collector, increasing the risk of damage to the negative electrode current collector and thus affecting battery performance.

[0004] Summary of the Invention

[0005] The present application provides a battery cell. The battery cell includes an electrode assembly; the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet; the negative electrode sheet includes a negative electrode composite current collector and a negative electrode active layer located on at least one surface of the negative electrode composite current collector; the negative electrode composite current collector includes a polymer material support layer and a conductive layer located on a surface of the polymer material support layer.

[0006] In the above battery cell, the negative electrode composite current collector including the polymer material support layer can reduce the impact of the negative electrode active layer expansion on the negative electrode composite current collector and reduce the risk of damage to the negative electrode composite current collector during use of the battery cell.

[0007] In some embodiments, the elongation at break of the negative electrode composite current collector is ≥30%. A higher elongation at break of the negative electrode composite current collector can further reduce the risk of damage to the negative electrode composite current collector.

[0008] In some embodiments, the elongation at break of the negative electrode composite current collector is 30% to 150%. The elongation at break of the negative electrode composite current collector within this range can achieve both good fracture resistance and good processing performance, facilitating the processing of the negative electrode composite current collector that meets the elongation at break condition.

[0009] In some embodiments, the electrode assembly is constructed as a flat structure, and includes a straight portion and corner portions located at both ends of the straight portion. By providing a negative electrode composite current collector including a polymer material support layer, the negative electrode composite current collector at the corners of the battery cell can maintain a relatively stable structure during use of the battery cell, reducing the risk of damage to the negative electrode composite current collector at the corners.

[0010] In some embodiments, at a battery cell SOC of 97%, the minimum gap between adjacent positive and negative electrode sheets at the corner is 20 μm to 40 μm. Within this range, the minimum gap between adjacent positive and negative electrode sheets at the corner of the battery cell at 97% SOC allows for better electrolyte penetration of the positive and negative electrode sheets, and reduces the risk of short circuits caused by contact between the positive and negative electrode sheets.

[0011] In some embodiments, at a 3% SOC of the battery cell, the minimum gap between adjacent positive and negative electrode sheets at the corner is 30 μm to 80 μm. Within this range, the minimum gap between adjacent positive and negative electrode sheets at the corner of the battery cell at 3% SOC allows for better electrolyte penetration of the positive and negative electrode sheets, and reduces the risk of short circuits caused by contact between the positive and negative electrode sheets.

[0012] In some embodiments, the negative electrode active material of the negative electrode active layer includes a silicon material. The negative electrode active material including the silicon material can increase the energy density of the battery.

[0013] In some embodiments, the mass percentage of the silicon material in the negative electrode active material is less than or equal to 5%, and the elongation at break of the negative electrode composite current collector is 60% to 100%.

[0014] In some embodiments, the mass percentage of the silicon material in the negative electrode active material is greater than 5% and less than or equal to 15%, and the elongation at break of the negative electrode composite current collector is 80% to 120%.

[0015] In some embodiments, the mass percentage of the silicon material in the negative electrode active material is greater than 15% and less than or equal to 25%, and the elongation at break of the negative electrode composite current collector is 90% to 130%.

[0016] In some embodiments, the mass percentage of the silicon material in the negative electrode active material is greater than 25% and less than or equal to 50%, and the elongation at break of the negative electrode composite current collector is 90% to 150%.

[0017] In some embodiments, the silicon material includes at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-graphene composite materials, and silicon-carbon nanotube composite materials.

[0018] In some embodiments, the polymer support layer comprises a polymer material having a number average molecular weight of 6000 to 9500. Polymer materials with a number average molecular weight within this range can enable the polymer support layer to have both good elongation and good processing properties.

[0019] In some embodiments, the polymer material includes at least one of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, and polyethylene.

[0020] In some embodiments, the battery cell includes a housing for accommodating the electrode assembly.

[0021] In some embodiments, the housing is square in shape and includes a shell and at least one end cover; wherein, the shell has an opening at only one end, and the end cover covers the opening; or both ends of the shell have openings, and the two end covers respectively cover the two openings.

[0022] In some embodiments, the shell is a soft package structure, and the material of the shell includes aluminum-plastic film.

[0023] In some embodiments, the housing is shaped like a cylinder, and includes a shell and at least one end cover, wherein the end cover covers an opening of the shell, and an outer diameter of the cylinder is greater than or equal to 30 mm.

[0024] A battery comprises the battery cell.

[0025] An electrical device comprises at least one of the battery cell and the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered as limiting the scope of the disclosed application, the embodiments or examples currently described, and any of the best modes currently understood for these applications. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the accompanying drawings:

[0027] FIG1 is a schematic diagram of a battery according to one embodiment of the present application.

[0028] FIG2 is an exploded view of the battery shown in FIG1 according to one embodiment of the present application.

[0029] FIG3 is a schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application.

[0030] Explanation of the accompanying reference numerals: 1. Battery cell; 11. Housing; 12. Electrode assembly; 13. Cover plate; 2. Electrical device.

[0031] In order to better describe and illustrate the embodiments and / or examples of the inventions disclosed herein, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered to limit the scope of the disclosed inventions, the presently described embodiments and / or examples, and any of the best modes currently understood for these inventions. DETAILED DESCRIPTION

[0032] To facilitate understanding of the present application, a more comprehensive description of the present application will be provided below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] The "ranges" disclosed in this application can be defined in the form of lower limits and upper limits. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. Ranges defined in this way can be inclusive or exclusive of the end values, any end value can be included or excluded independently, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4, and 5 are also listed, the following ranges are all expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise specified, the numerical range "a to b" is an abbreviation for any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to listing the parameter as, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on. For example, when a parameter is expressed as an integer selected from "2-10," this is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0035] In this application, "a plurality of" or "a plurality of" refers to a number greater than or equal to 2 unless otherwise specified. For example, "one or more" means one or more than or equal to two.

[0036] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0037] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment or implementation of the present application. The appearance of such phrases in various locations in the specification does not necessarily refer to the same embodiment, nor does it necessarily refer to independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments. References to "implementations" herein have a similar understanding.

[0038] Those skilled in the art will appreciate that, in the methods of each embodiment or example, the order in which the steps are written does not imply a strict order of execution and does not constitute any limitation on the implementation process, and the detailed order of execution of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of the present application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, it is mentioned that the method may also include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0039] In this application, open technical features or technical solutions described with words such as "contain," "include," and "includes" do not exclude additional members beyond the listed members unless otherwise specified, and can be regarded as providing both closed features or solutions consisting of the listed members and open features or solutions that include additional members beyond the listed members. For example, if A includes a1, a2, and a3, it may or may not include other members unless otherwise specified. This can be regarded as providing both the feature or solution of "A consists of a1, a2, and a3" and the feature or solution of "A includes not only a1, a2, and a3, but also other members."

[0040] In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0041] In this application, the terms "optionally," "optional," and "optional" mean optional or dispensable, i.e., they refer to either option being selected from two parallel options: "with" or "without." If a technical solution contains multiple "optional" clauses, each "optional" clause is considered independent unless otherwise specified and there are no conflicts or constraints.

[0042] One embodiment of the present application provides a battery cell. The battery cell includes an electrode assembly; the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator positioned between the positive and negative electrode sheets; the negative electrode sheet includes a negative electrode composite current collector and a negative electrode active layer positioned on at least one surface of the negative electrode composite current collector; the negative electrode composite current collector includes a polymer material support layer and a conductive layer positioned on a surface of the polymer material support layer. In the battery cell of this embodiment, the provision of the negative electrode composite current collector including the polymer material support layer can reduce the impact of the negative electrode active layer's expansion on the negative electrode composite current collector, thereby reducing the risk of damage to the negative electrode composite current collector during use of the battery cell.

[0043] In some embodiments, the elongation at break of the negative electrode composite current collector is ≥30%. A higher elongation at break of the negative electrode composite current collector can further reduce the risk of damage to the negative electrode composite current collector.

[0044] The elongation at break of the negative electrode composite current collector in this application can be tested in the following way: disassemble the battery cell at 97% SOC to obtain the negative electrode pole piece, remove the active layer on the surface of the negative electrode pole piece, and obtain the negative electrode composite current collector. Cut the negative electrode composite current collector to obtain a current collector sample with a length of 150 mm and a width of 25 mm. Fix the sample on a tensile testing machine, and clamp the sample with chucks at both ends of the tensile testing machine in the length direction of the sample. The distance between the chucks is L0, and L0 is usually 50 mm. Control the tensile testing machine at a speed of 5 m / min and stretch until the sample breaks. At this time, the distance between the chucks is L1. The elongation at break of the sample = (L1-L0) / L0×100%. It can be understood that SOC represents the state of charge of the battery cell.

[0045] In some embodiments, the elongation at break of the negative electrode composite current collector is 30% to 150%. Within this range, the elongation at break of the negative electrode composite current collector can achieve both good fracture resistance and good processing performance, facilitating the processing of the negative electrode composite current collector that meets the elongation at break condition. Alternatively, the elongation at break of the negative electrode composite current collector can be 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140%, 150%, or any value within a range consisting of any two of the above values. Further optionally, the elongation at break of the negative electrode composite current collector is 60% to 100%.

[0046] In some embodiments, the electrode assembly is constructed as a flat structure, and the electrode assembly includes a straight portion and corner portions provided at both ends of the straight portion. In this case, the corresponding battery cell is constructed as a wound battery cell. In this battery cell, the expansion of the active layer has a more significant effect on the corner portion than on the straight portion. By providing a negative electrode composite current collector including a polymer material support layer, the negative electrode composite current collector at the corner portion of the battery cell can maintain a relatively stable structure during the use of the battery cell, reducing the risk of damage to the negative electrode composite current collector at the corner.

[0047] In some embodiments, when the battery cell is at 97% SOC, at the corner of the electrode assembly, the minimum gap (i.e., the Gap value) between adjacent positive and negative electrode sheets is 20 μm to 40 μm. When the battery cell is at 97% SOC, at the corner of the electrode assembly, the minimum gap between adjacent positive and negative electrode sheets within this range can allow the electrolyte to better infiltrate the positive and negative electrode sheets, and can also reduce the risk of short circuit due to contact between the positive and negative electrode sheets. Optionally, when the battery cell is at 97% SOC, at the corner of the electrode assembly, the minimum gap between adjacent positive and negative electrode sheets can be 20 μm, 22 μm, 25 μm, 28 μm, 30 μm, 32 μm, 35 μm, 38 μm, 40 μm, and any value within the range consisting of any two of the above values.

[0048] In some embodiments, when the battery cell is at 3% SOC, at the corner of the electrode assembly, the minimum gap (i.e., the Gap value) between adjacent positive and negative electrode sheets is 30 μm to 80 μm. When the battery cell is at 3% SOC, at the corner of the electrode assembly, the minimum gap between adjacent positive and negative electrode sheets within this range can allow the electrolyte to better infiltrate the positive and negative electrode sheets, and can also reduce the risk of short circuit due to contact between the positive and negative electrode sheets. Optionally, when the battery cell is at 3% SOC, at the corner of the battery cell, the minimum gap between adjacent positive and negative electrode sheets can be 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, and any value within the range consisting of any two of the above values.

[0049] In this application, the Gap value can be obtained by the following test method: use an X-ray CT scanner for measurement, with the irradiation direction being 45° to the winding axis of the battery cell and two-dimensional imaging, and use the equipment ruler to measure the distance between 5 consecutive layers of negative electrode sheets. Then, the battery cell is disassembled to remove the electrode assembly, and the thickness of the positive electrode sheet, separator, and negative electrode sheet is measured with a micrometer. The Gap value is calculated by the formula: Gap value = [distance between 5 layers of negative electrode sheets - (positive electrode sheet thickness + negative electrode sheet thickness) × 4 - separator × 8)] / 8.

[0050] In some embodiments, the negative electrode active material of the negative electrode active layer includes a silicon material. The inclusion of a silicon material in the negative electrode active material can increase the energy density of the battery. At the same time, in the negative electrode composite current collector, the polymer material support layer can provide a buffer for the volume expansion of the silicon material. During the charging process of the battery cell, the silicon material undergoes volume expansion, and the buffering effect of the polymer material support layer can better release the expansion stress, reduce the difficulty of the electrolyte entering the negative electrode pole piece, improve the infiltration effect of the electrolyte on the negative electrode active material, and reduce the risk of lithium deposition on the surface of the negative electrode pole piece, thereby enabling the battery to have both higher energy density and better cycle performance. Furthermore, during the charging process of the battery cell, after the expansion stress of the silicon material is better released, the squeezing of the isolation membrane by the expansion of the silicon material will be better alleviated, thereby reducing the risk of closed pores in the isolation membrane, thereby allowing the electrolyte to pass through the isolation membrane smoothly, and allowing the battery to maintain better cycle performance.

[0051] Optionally, the silicon material includes at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-graphene composite material, and a silicon-carbon nanotube composite material. Further optionally, the negative electrode active material may also include graphite. Further optionally, the graphite includes at least one of artificial graphite and natural graphite.

[0052] In some embodiments, the 97% SOC thickness expansion rate of the negative electrode sheet is 2% to 10%. For example, the 97% SOC thickness expansion rate of the negative electrode sheet can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any value within a range consisting of any two of the above values.

[0053] The 97% SOC thickness expansion rate of the negative electrode sheet in this application can be measured by the following method: Take a battery cell at 97% SOC and 3% SOC, respectively, and disassemble it to obtain the negative electrode sheet. The thickness of the negative electrode sheet at 3% SOC is T0, and the thickness of the negative electrode sheet at 97% SOC is T1. The 97% SOC thickness expansion rate of the negative electrode sheet = (T1-T0) / T0×100%.

[0054] In some embodiments, the mass percentage of silicon material in the negative electrode active material is less than or equal to 5%, and the elongation at break of the negative electrode composite current collector is 60% to 100%. The mass percentage of silicon material in the negative electrode active material is set corresponding to the elongation at break of the negative electrode composite current collector, so that the silicon material and the negative electrode composite current collector are well matched, and the impact of silicon material expansion on the battery is alleviated. Optionally, the mass percentage of silicon material in the negative electrode active material can be 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 5%, and any value within the range consisting of any two of the above values. Optionally, the elongation at break of the negative electrode composite current collector may be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, or any value within the range consisting of any two of the above values.

[0055] In some embodiments, the mass percentage of silicon material in the negative electrode active material is greater than 5% and less than or equal to 15%, and the elongation at break of the negative electrode composite current collector is 80% to 120%. The mass percentage of silicon material in the negative electrode active material and the elongation at break of the negative electrode composite current collector are set correspondingly, so that the silicon material and the negative electrode composite current collector are well matched, and the impact of silicon material expansion on the battery is alleviated. Optionally, the mass percentage of silicon material in the negative electrode active material can be 5.1%, 5.3%, 5.5%, 5.8%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and any value within the range consisting of any two of the above values. Optionally, the elongation at break of the negative electrode composite current collector can be 80%, 85%, 90%, 95%, 100%, 105%, 100%, 105%, 110%, 115%, 120% and any value within the range consisting of any two of the above values.

[0056] In some embodiments, the mass percentage of silicon material in the negative electrode active material is greater than 15% and less than or equal to 25%, and the elongation at break of the negative electrode composite current collector is 90% to 130%. The mass percentage of silicon material in the negative electrode active material and the elongation at break of the negative electrode composite current collector are set correspondingly, so that the silicon material and the negative electrode composite current collector are better matched, and the impact of silicon material expansion on the battery is alleviated. Optionally, the mass percentage of silicon material in the negative electrode active material can be 15.1%, 15.3%, 15.5%, 15.8%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, and any value within the range consisting of any two of the above values. Optionally, the elongation at break of the negative electrode composite current collector may be 90%, 95%, 100%, 105%, 110%, 115%, 120%, 125%, 130%, or any value within the range consisting of any two of the above values.

[0057] In some embodiments, the mass percentage of silicon material in the negative electrode active material is greater than 25% and less than or equal to 50%, and the elongation at break of the negative electrode composite current collector is 90% to 150%. The mass percentage of silicon material in the negative electrode active material and the elongation at break of the negative electrode composite current collector are set correspondingly, so that the silicon material and the negative electrode composite current collector are well matched, the impact of silicon material expansion on the battery is alleviated, and the battery maintains good cycle performance. Optionally, the mass percentage of silicon material in the negative electrode active material can be 25.1%, 25.3%, 25.5%, 25.8%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, and any value within the range consisting of any two of the above values. Optionally, the elongation at break of the negative electrode composite current collector may be 90%, 95%, 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, 140%, 150%, or any value within the range of any two of the above values.

[0058] In some embodiments, the material of the conductive layer includes at least one of copper and a copper alloy.

[0059] In some embodiments, the polymer material support layer comprises a polymer material, and the number average molecular weight of the polymer material is 6500 to 9500. The polymer material with a number average molecular weight within this range can enable the polymer material support layer to have both good elongation and good processing performance. It is understandable that good elongation performance is manifested in that the polymer material support layer has a more suitable elongation at break. Good processing performance is manifested in that the polymer material support layer can be more conveniently obtained by casting a polymer material into a film. Optionally, the number average molecular weight of the polymer material can be 6000 to 6500, 6500 to 7000, 7000 to 7500, 7500 to 8000, 8000 to 8500, 8500 to 9000, 9000 to 95000, etc. Further optionally, the number average molecular weight of the polymer material can be about 6000, about 7000, about 8000, about 9000, etc. Further optionally, the polymer material includes at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and polyethylene (PE).

[0060] In some embodiments, the elongation at break of the polymer material support layer is ≥100%. A polymer material support layer with an elongation at break within this range has good elongation properties. On the one hand, it can maintain a relatively stable structure of the negative electrode composite current collector during the use of the battery cell, reducing the risk of damage to the negative electrode composite current collector. On the other hand, during the cycle of the battery cell, the polymer material support layer can buffer the expansion of the electrode through its own compression, so that a relatively appropriate distance is maintained between adjacent positive and negative electrode sheets, thereby allowing the electrolyte to better infiltrate the electrode sheets, while also reducing the risk of short circuits caused by contact between the positive and negative electrode sheets. Optionally, the elongation at break of the polymer material support layer is 70% to 140%. Optionally, the elongation at break of the polymer material support layer can be 70%, 75%, 80%, 85%, 90%, 95%, 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, 140% and any value within the range consisting of any two of the above values.

[0061] The elongation at break of the polymer material support layer in the present application can be tested in the following way: the polymer material corresponding to the polymer material support layer is cast into a film with a thickness of 4.5 μm. The current collector is cut to obtain a sample with a length of 150 mm and a width of 25 mm. The sample is fixed on a tensile testing machine, and the chucks at both ends of the tensile testing machine clamp the sample in the length direction of the sample. The distance between the chucks is L0, and L0 is usually 50 mm. The tensile testing machine is controlled at a speed of 5 m / min and stretched until the sample breaks. At this time, the distance between the chucks is L1. The elongation at break of the sample = (L1-L0) / L0×100%.

[0062] In some embodiments, the battery cell includes a housing for housing the electrode assembly.

[0063] In some embodiments, the housing is square in shape and includes a shell and at least one end cap; wherein, the shell has an opening at only one end and the end cap covers the opening; or both ends of the shell have openings and the two end caps cover the two openings respectively.

[0064] In some embodiments, the shell is a soft package structure, and the material of the shell includes aluminum-plastic film.

[0065] In some embodiments, the outer shell is in the shape of a cylinder, and includes a shell and at least one end cap, the end cap covers the opening of the shell, and the outer diameter of the cylinder is greater than or equal to 30 mm.

[0066] Another embodiment of the present application provides a battery comprising the above-mentioned battery cell.

[0067] Another embodiment of the present application provides an electrical device, which includes at least one of the above-mentioned battery cells and the above-mentioned batteries.

[0068] The battery cell, battery, and electrical device of the present application will be described below with appropriate reference to the accompanying drawings.

[0069] Typically, a battery cell consists of a positive electrode, a negative electrode, an electrolyte, and a separator. During the battery's charge and discharge processes, active ions are inserted and removed between the positive and negative electrodes. The electrolyte conducts ions between the positive and negative electrodes. The separator, located between the positive and negative electrodes, primarily prevents short circuits between the positive and negative electrodes while allowing ions to pass through.

[0070] Positive electrode

[0071] The positive electrode sheet includes a positive electrode current collector and a positive electrode active layer disposed on at least one surface of the positive electrode current collector, wherein the positive electrode active layer includes a positive electrode active material.

[0072] As a non-limiting example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active layer is disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0073] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material support layer and a conductive layer formed on at least one surface of the polymer material support layer. The composite current collector may be obtained by forming a conductive material on a polymer material substrate. In the positive electrode current collector, the conductive material includes a metal material. Non-limiting examples of metal materials may include one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. In the positive electrode current collector, non-limiting examples of the polymer material substrate may include one or more of substrates such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0074] In some embodiments, the positive electrode active material may be a positive electrode active material for a battery that is well known in the art. As a non-limiting example, the positive electrode active material may include one or more of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxide (such as LiCoO2), lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their modified compounds. Non-limiting examples of olivine-structured lithium-containing phosphates may include, but are not limited to, one or more of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Non-limiting examples of lithium cobalt oxides may include LiCoO2; non-limiting examples of lithium nickel oxides may include LiNiO2; non-limiting examples of lithium manganese oxides may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxides may include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ) etc. Non-limiting examples of lithium nickel cobalt aluminum oxide may include LiNi 0.8 Co 0.15 Al 0.05 O2.

[0075] In some embodiments, the positive electrode active layer may further optionally include a binder. As non-limiting examples, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0076] In some embodiments, the positive electrode active layer may further include a conductive agent. As non-limiting examples, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0077] In some embodiments, the positive electrode sheet can be prepared by the following method: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder, and any other components, are dispersed in a solvent to form a positive electrode slurry; the positive electrode slurry is coated on at least one side of the positive electrode current collector, and after drying, cold pressing, and other processes, the positive electrode sheet can be obtained. The type of solvent can be selected from but not limited to any of the aforementioned embodiments, such as N-methylpyrrolidone (NMP). The surface of the positive electrode current collector coated with the positive electrode slurry can be on a single surface of the positive electrode current collector or on both surfaces of the positive electrode current collector. The surface of the positive electrode current collector coated with the positive electrode slurry can be on a single surface of the positive electrode current collector or on both surfaces of the positive electrode current collector. The solid content of the positive electrode slurry can be 40wt% to 80wt%. The viscosity of the positive electrode slurry at room temperature can be adjusted to 5000mPa·s to 25000mPa·s. When applying the positive electrode slurry, the coating unit area density based on dry weight (excluding solvent) can be 15 mg / cm 2 ~35mg / cm 2 The compaction density of the positive electrode can be 3.0g / cm 3 ~3.6g / cm 3, optional 3.3g / cm 3 ~3.5g / cm 3 .

[0078] Negative electrode

[0079] The negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode active layer includes a negative electrode active material.

[0080] As a non-limiting example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active layer is disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0081] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material support layer and a conductive layer formed on at least one surface of the polymer material support layer. The composite current collector may be obtained by forming a conductive material on a polymer material substrate. In the negative electrode current collector, the conductive material includes a metal material. Non-limiting examples of the metal material may include one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. In the negative electrode current collector, non-limiting examples of the polymer material substrate may include one or more of substrates such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0082] In some of these embodiments, the negative electrode active material may be a negative electrode active material for a battery that is well known in the art. As a non-limiting example, the negative electrode active material may include one or more of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. Silicon-based materials may include one or more of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxides, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0083] In some embodiments, the negative electrode active layer may further include a binder. The binder may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0084] In some embodiments, the negative electrode active layer may further include a conductive agent, which may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0085] In some embodiments, the negative electrode active layer may optionally further include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0086] In some embodiments, the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (a non-limiting example of the solvent is deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on at least one side of the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained. The surface of the negative electrode current collector coated with the negative electrode slurry can be a single surface of the negative electrode current collector or on both surfaces of the negative electrode current collector. The solid content of the negative electrode slurry can be 40wt% to 60wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000mPa·s to 10000mPa·s. When coating the negative electrode slurry, the coating unit surface density on a dry weight basis (excluding the solvent) can be 75g / m 2 ~220g / m 2 The compaction density of the negative electrode can be 1.0g / cm 3 ~1.8g / cm 3 .

[0087] electrolytes

[0088] The electrolyte conducts ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, and the electrolyte can be selected based on the needs. For example, the electrolyte can be liquid, gel, or solid.

[0089] In some embodiments, the electrolyte is an electrolyte solution comprising an electrolyte salt and a solvent.

[0090] In some embodiments, the electrolyte salt may include one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonyl imide (LiFSI), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorophosphate (LiPO2F2), lithium difluorooxalatoborate (LiDFOB), lithium dioxalatoborate (LiBOB), lithium difluorodioxalatophosphate (LiDFOP) and lithium tetrafluorooxalatophosphate (LiTFOP).

[0091] In some embodiments, the solvent may include ethylene carbonate (EC, ), propylene carbonate (PC, ), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate One or more of fluoroethylene carbonate (FEC), methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.

[0092] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, and additives that improve battery high or low temperature performance.

[0093] In some embodiments, the additives in the electrolyte may include, but are not limited to, one or more of fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), trifluoromethylethylene carbonate (TFPC), and the like.

[0094] Isolation film

[0095] In some embodiments, the battery cell further includes a separator. This application has no particular limitation on the type of separator, and any known porous separator with good chemical and mechanical stability can be selected.

[0096] In some embodiments, the material of the separator may include one or more of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0097] In some embodiments, the isolation film has a thickness of 6 μm to 40 μm, and may optionally be 12 μm to 20 μm.

[0098] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator can be formed into an electrode assembly through a winding process or a lamination process.

[0099] In some embodiments, the battery cell may include an outer packaging that can be used to encapsulate the electrode assembly and the electrolyte.

[0100] In some embodiments, the outer packaging of the battery cell may be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. Alternatively, the outer packaging of the battery cell may be a soft shell, such as a pouch-type soft shell. The soft shell may be made of plastic. Non-limiting examples of the plastic include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0101] A battery includes at least one battery cell. A battery may include one or more battery cells.

[0102] In this application, unless otherwise specified, a "battery cell" refers to a basic unit that can achieve the mutual conversion of chemical energy and electrical energy. Further, generally speaking, it includes at least a positive electrode plate, a negative electrode plate, and an electrolyte. During the battery's charge and discharge process, active ions are embedded in and out of the positive and negative electrode plates. The electrolyte plays the role of conducting active ions between the positive and negative electrode plates.

[0103] The present application has no particular limitation on the shape of the battery cell, which may be cylindrical, square, or any other shape. For example, FIG1 shows a battery cell 1 having a square structure as an example.

[0104] In some embodiments, referring to Figure 2, the outer packaging may include a shell 11 and a cover plate 13. The shell 11 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity. The shell 11 has an opening connected to the receiving cavity, and the cover plate 13 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can be formed into an electrode assembly 12 through a winding process or a lamination process. The electrode assembly 12 is encapsulated in the receiving cavity. The electrolyte is impregnated in the electrode assembly 12. The number of electrode assemblies 12 contained in the battery cell 1 can be one or more, and those skilled in the art can select according to actual needs.

[0105] The battery may be a battery module or a battery pack.

[0106] A battery module includes at least one battery cell. The number of battery cells contained in a battery module can be one or more, and those skilled in the art can select an appropriate number based on the application and capacity of the battery module.

[0107] In a battery module, multiple battery cells can be arranged in sequence along the length of the battery module. Of course, they can also be arranged in any other manner. Further, the multiple battery cells can be fixed by fasteners.

[0108] Optionally, the battery module may further include a housing having an accommodation space, wherein the plurality of battery cells are accommodated in the accommodation space.

[0109] In some embodiments, the battery modules may be assembled into a battery pack. The battery pack may contain one or more battery modules. Those skilled in the art may select an appropriate number based on the application and capacity of the battery pack.

[0110] A battery pack may include a battery box and multiple battery modules disposed within the box. The battery box comprises an upper case and a lower case. The upper case can be placed over the lower case to form an enclosed space for accommodating the battery modules. The multiple battery modules can be arranged in any manner within the battery box.

[0111] In addition, the present application also provides an electrical device, which includes the battery provided in the present application. The battery can serve as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device can include, but is not limited to, mobile devices, electric vehicles, electric trains, ships, satellites, energy storage systems, etc. Among them, mobile devices can be, for example, mobile phones, laptop computers, etc.; electric vehicles can be, for example, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc., but are not limited to these.

[0112] As an electrical device, a battery can be selected according to its usage requirements.

[0113] Figure 3 shows an example of an electric device 2. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the electric device, a battery pack or battery module can be used.

[0114] Another example device may be a mobile phone, a tablet computer, a laptop computer, etc. Such a device is generally required to be lightweight and thin, and may use a battery as a power source.

[0115] In order to make the technical problems, technical solutions and beneficial effects solved by this application clearer, the application will be further described in detail below with reference to the embodiments and drawings. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0116] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments used without specifying the manufacturer are commercially available conventional products.

[0117] Example 1

[0118] (1) Prepare the positive electrode sheet.

[0119] The positive electrode active material, LiFePO4, the conductive agent, carbon black (Super P), and the binder, polyvinylidene fluoride (PVDF), were mixed uniformly in an appropriate amount of NMP solvent at a mass ratio of 97:1:2 to create a positive electrode slurry. The slurry was evenly coated on the surface of aluminum foil, dried, cold-pressed, and then die-cut and slit to produce positive electrode sheets. The aluminum foil had an elongation at break of 7.2% and a thickness of 13μm.

[0120] (2) Prepare the negative electrode sheet.

[0121] The negative electrode active material, conductive agent Super P, thickener (CMC), and binder (SBR) are added to a certain amount of water in a mass ratio of 95:3:1:1, and stirred evenly to prepare the negative electrode active slurry. The negative electrode material includes elemental silicon and graphite; the negative electrode active slurry is evenly coated on the surface of the negative electrode composite current collector, dried and cold pressed, and then die-cut and slit to make the negative electrode sheet.

[0122] The negative electrode composite current collector includes a PP support layer and copper layers on two opposing surfaces of the PP support layer. The PP support layer is 4.5 μm thick, and the single-sided copper layer is 1 μm thick. The total thickness of the negative electrode composite current collector is 6.5 μm.

[0123] (3) Preparation of isolation membrane.

[0124] Polyethylene is used as a base film, and aluminum oxide with a thickness of 3 μm is coated on the base film to obtain an isolation film.

[0125] (4) Prepare electrolyte.

[0126] Lithium hexafluorophosphate is dissolved in a solvent having a volume ratio of DMC:DEC:EC of 1:1:1 to obtain a lithium-ion battery electrolyte.

[0127] (5) Prepare a battery.

[0128] The positive electrode sheet, the negative electrode sheet and the separator are wound into an electrode assembly, and then the battery cell in this embodiment is obtained through packaging, liquid injection, formation and other processes.

[0129] Example 2 to Example 6

[0130] Compared with Example 1, the differences between Examples 2 to 6 are that in the negative electrode sheet, the mass percentage of silicon material in the negative electrode active material, the number average molecular weight of PET, and the elongation at break of the negative electrode composite current collector are different, as shown in Table 1.

[0131] Comparative Example 1

[0132] Compared with Example 1, this comparative example differs in that the positive electrode current collector in the positive electrode sheet is aluminum foil. The aluminum foil has an elongation at break of 7.2% and a thickness of 13 μm. The negative electrode current collector in the negative electrode sheet is copper foil. The copper foil has an elongation at break of 2.3% and a thickness of 6.5 μm.

[0133] Test Case

[0134] The damage to the negative electrode current collectors of the batteries used in the examples and comparative examples was tested. During the cycling of the battery cells, X-ray CT scanners were used to image the negative electrode current collectors after every 5% SOH decrease in capacity. If cracks appeared in the electrode sheets in the two-dimensional images, the current collectors were considered broken, and the SOH decrease corresponding to the cracking was recorded. The results are shown in Table 1.

[0135] Table 1

[0136] As can be seen from Table 1, compared with Comparative Example 1, the negative electrode composite current collectors in Examples 1 to 6 did not crack during the cycle of the battery cell, indicating that the introduction of the negative electrode composite current collector can reduce the risk of damage to the negative electrode current collector during the use of the battery cell.

[0137] As can be seen from Examples 1 to 6, when the mass percentage of silicon material in the negative electrode active material varies, using a negative electrode composite current collector with an appropriate elongation at break allows the negative electrode composite current collector to maintain a relatively stable structure without cracking during the cycling of the battery cell. Furthermore, as the mass percentage of silicon material in the negative electrode active material increases, using a negative electrode composite current collector with an increased elongation at break allows the negative electrode composite current collector to maintain a relatively stable structure without cracking during the cycling of the battery cell.

[0138] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0139] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A battery cell, comprising an electrode assembly; the electrode assembly comprises a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet; the negative electrode sheet comprises a negative electrode composite current collector and a negative electrode active layer located on at least one surface of the negative electrode composite current collector, the negative electrode composite current collector comprises a polymer material support layer and a conductive layer located on a surface of the polymer material support layer.

2. The battery cell according to claim 1, wherein: The elongation at break of the negative electrode composite current collector is ≥30%.

3. The battery cell according to any one of claims 1 to 2, wherein: The fracture elongation of the negative electrode composite current collector is 30% to 150%.

4. The battery cell according to any one of claims 1 to 3, wherein The electrode assembly is constructed as a flat structure, and includes a straight portion and corner portions provided at both ends of the straight portion.

5. The battery cell according to claim 4, wherein: When the battery cell is at a SOC of 97%, at the corner portion, a minimum gap between the adjacent positive electrode tabs and the adjacent negative electrode tabs is 20 μm to 40 μm.

6. The battery cell according to any one of claims 4 to 5, wherein When the battery cell is at a 3% SOC, at the corner portion, a minimum gap between the adjacent positive electrode tabs and the adjacent negative electrode tabs is 30 μm to 80 μm.

7. The battery cell according to any one of claims 1 to 6, wherein: The negative electrode active material of the negative electrode active layer includes silicon material.

8. The battery cell according to claim 7, wherein: The mass percentage of the silicon material in the negative electrode active material is less than or equal to 5%, and the fracture elongation of the negative electrode composite current collector is 60% to 100%.

9. The battery cell according to claim 7, wherein: The mass percentage of the silicon material in the negative electrode active material is greater than 5% and less than or equal to 15%, and the fracture elongation of the negative electrode composite current collector is 80% to 120%.

10. The battery cell according to claim 7, wherein: The mass percentage of the silicon material in the negative electrode active material is greater than 15% and less than or equal to 25%, and the elongation at break of the negative electrode composite current collector is 90% to 130%.

11. The battery cell according to claim 7, wherein: The mass percentage of the silicon material in the negative electrode active material is greater than 25% and less than or equal to 50%, and the fracture elongation of the negative electrode composite current collector is 90% to 150%.

12. The battery cell according to any one of claims 7 to 11, wherein: The silicon material includes at least one of elemental silicon, silicon oxide, silicon-carbon composite, silicon-graphene composite material and silicon-carbon nanotube composite material.

13. The battery cell according to any one of claims 1 to 12, wherein: The polymer material supporting layer comprises a polymer material, and the number average molecular weight of the polymer material is 6000-9500.

14. The battery cell according to claim 13, wherein: The polymer material includes at least one of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene and polyethylene.

15. The battery cell according to claims 1 to 14, wherein: The battery cell includes a housing for accommodating the electrode assembly.

16. The battery cell according to claim 15, wherein: The outer shell is in a square shape and comprises a shell and at least one end cover; wherein the housing has an opening at only one end, and the end cover covers the opening; or Both ends of the shell have openings, and the two end covers cover the two openings respectively.

17. The battery cell according to claim 15, wherein: The shell is a soft package structure, and the material of the shell includes aluminum-plastic film.

18. The battery cell according to claim 15, wherein: The outer shell is in the shape of a cylinder and comprises a shell and at least one end cover, wherein the end cover covers an opening of the shell, and an outer diameter of the cylinder is greater than or equal to 30 mm.

19. A battery comprising the battery cell according to any one of claims 1 to 18.

20. An electrical device comprising at least one of the battery cell according to any one of claims 1 to 18 and the battery according to claim 19.

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