Battery cell, battery and electrical device

Abstract

A battery cell (20), comprising: a housing in which a recording chamber is formed; an electrode assembly arranged in the recording space; and an electrolyte solution arranged in the receiving chamber, wherein an electrolyte retention coefficient a and a packing fraction b of the battery cell (20) satisfy the following relationship: 2 ≤ a / b ≤ 3, and the electrolyte retention coefficient a is given in units of g / Ah.

Description

TECHNICAL AREA

[0001] This application relates to the technical field of batteries, in particular to a battery cell, a battery and an electrical device. BACKGROUND

[0002] Batteries are used in consumer electronics, electric vehicles, aerospace, and other fields due to their high energy density, excellent cycle stability, low self-discharge rate, high safety performance, and other properties. The energy density and cycle stability of batteries are of great importance in these areas.

[0003] According to current technology, increasing the battery's energy density can lead to a deterioration in its cycle life. In other words, the problem of achieving both high energy density and high cycle life simultaneously arises with batteries. SHORT DESCRIPTION

[0004] This application describes a battery cell, a battery and an electrical device that can simultaneously achieve high energy density and high cycle stability.

[0005] According to a first aspect, this application provides a battery cell. The battery cell comprises a housing, an electrode assembly, and an electrolyte solution. A receiving space is formed within the housing. The electrode assembly is arranged in the receiving space. The electrolyte solution is located in the receiving space. An electrolyte retention coefficient a and a packing fraction b of the battery cell satisfy the following relationship: 2 ≤ a / b ≤ 3, and the electrolyte retention coefficient a is given in units of g / Ah.

[0006] In the above embodiment, the ratio between the electrolyte retention coefficient a and the packing fraction b of the battery cell is adjusted so that it falls within the above-mentioned suitable range, thereby giving the battery cell both a high energy density and a relatively high cycle life.

[0007] In some embodiments of this application, the electrolyte retention coefficient a and the packing ratio b of the battery cell satisfy the following relationship: 2.25 ≤ a / b ≤ 2.90. The a / b ratio, which lies within the above-mentioned range, can give the battery cell both a relatively high energy density and a relatively high cycle life.

[0008] In some embodiments of this application, the electrolyte retention coefficient a lies within a range of 1.4 g / Ah to 2.97 g / Ah. An electrolyte retention coefficient a falling within the aforementioned suitable range can increase the energy density of the battery cell while simultaneously enabling the battery cell to retain a reasonable amount of electrolyte solution, thereby achieving the objective of improving the cycle stability of the battery cell.

[0009] In some embodiments of this application, the electrolyte retention coefficient a lies within a range of 1.8 g / Ah to 2.3 g / Ah. An electrolyte retention coefficient a that falls within the aforementioned suitable range can increase the energy density of the battery cell and simultaneously further improve its cycle stability.

[0010] In some embodiments of this application, the packing fraction b of the battery cell lies within a range of 80% to 99%. The packing fraction b of the battery cell that falls within the aforementioned suitable range can give the battery cell a relatively high cycle life and simultaneously increase the energy density of the battery cell.

[0011] In some embodiments of this application, the packing fraction b of the battery cell lies within a value range of 85% to 95%. The packing fraction b of the battery cell that falls within the aforementioned suitable range can improve the cycle stability of the battery cell and simultaneously further increase the energy density of the battery cell.

[0012] In some embodiments of this application, the electrode assembly comprises a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate comprises a positive current collector and a positive active material layer arranged on at least one surface of the positive current collector. The positive active material layer contains a positive active material. The negative electrode plate comprises a negative current collector and a negative active material layer arranged on at least one surface of the negative current collector. The negative active material layer contains a negative active material. The separator is arranged between the positive electrode plate and the negative electrode plate.The positive active material is at least one of the following: lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, a lithium-rich positive active material, or a ternary positive active material. The negative active material is at least one selected from a carbon-containing negative active material, a silicon-containing negative active material, an alloyed negative active material, a lithium-containing negative active material, or a tin-containing negative active material. In the electrode assembly described above, the appropriate selection of the positive and negative active materials can improve the energy density and cycle life of the battery cell.

[0013] In some embodiments of this application, the ternary positive active material is represented by the following chemical formula: LiNi x Co y NM 1-x-y-zO2, where N is selected from Mn or Al, M is at least one of Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti, 0 ≤ x < 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1 and x + y + z ≤ 1. The ternary positive active material represented by the chemical formula above can further increase the energy density of the battery cell.

[0014] In some embodiments of this application, the lithium-rich positive active material is represented by the following chemical formula: Li2MnO3·(1-c)LiAO2, where A is at least one element selected from Ni, Co or Mn; and 0 ≤ c < 1. The lithium-rich positive active material represented by the above chemical formula can also further increase the energy density of the battery cell.

[0015] In some embodiments of this application, the electrolyte solution contains an organic solvent and an electrolyte salt, and the organic solvent is at least one compound selected from an ester or ether compound. The organic solvent selected from at least one ester or ether compound improves the cycle life of the battery cell.

[0016] In some embodiments of this application, the ester compound is at least one of the following: dimethyl carbonate, diethyl carbonate, propylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, ethyl formate, ethyl acetate, or ethylene carbonate. The ester compound, which is one or more of the aforementioned ester compounds, can further improve the cycle life of the battery cell.

[0017] In some embodiments of this application, the ether compound is at least one of tetrahydrofuran, 2-methylfuran, 3-methylfuran, 2-ethylfuran, 2-propylfuran, 2-butylfuran, 2,3-dimethylfuran, 2,4-dimethylfuran, 2,5-dimethylfuran, pyran, 2-methylpyran, 3-methylpyran, 4-methylpyran, benzofuran, or 2-(2-nitrovinyl)furan. The ether compound, which is one or more of the aforementioned ether compounds, can further improve the cycle stability of the battery cell.

[0018] In some embodiments of this application, the concentration of the electrolyte salt in the electrolyte solution is 0.6 mol / L to 2.0 mol / L. If the concentration of the electrolyte salt in the electrolyte solution is within the aforementioned range, it improves the cycle stability of the battery cell.

[0019] In some embodiments of this application, the electrolyte salt is at least one selected from lithium hexafluorophosphate or lithium bis(fluorosulfonyl)imide. The electrolyte salt selected from the aforementioned lithium salts can improve the high-temperature storage performance of the battery cell.

[0020] According to a second aspect, one embodiment of this application provides a battery. The battery contains the battery cell described in one of the embodiments above. Since the battery contains the battery cell disclosed in one of the embodiments above, the battery achieves the technical effects of the battery cell, which will not be discussed in detail here.

[0021] According to a third aspect, an embodiment of this application provides an electrical device. The electrical device contains the battery described in the embodiment above.

[0022] The foregoing description is merely an overview of the technical solutions of this application. Some specific embodiments of this application are described below for illustrative purposes in order to provide a clearer understanding of the technical solutions of this application, to facilitate the implementation of the technical solutions based on the subject matter of this application, and to make the foregoing and other objectives, features, and advantages of this application clearer and more understandable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Upon reading the following detailed description of the exemplary embodiments, various other advantages and benefits will become clearly apparent to the person skilled in the art. The drawings serve only to illustrate the exemplary embodiments and do not restrict the application. The same reference number refers to the same component in all drawings. In the drawings: Fig. Figure 1 is a schematic structural diagram of a vehicle according to some embodiments of this application; Fig. 2 is an exploded view of a battery according to some embodiments of this application; Fig. Figure 3 is a schematic structural diagram of a battery cell according to some embodiments of this application; and Fig. Figure 4 is an exploded view of a battery cell according to some embodiments of this application. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0024] Some embodiments of the technical solutions of this application are described in detail below with reference to the drawings. The following embodiments are intended only as examples to describe the technical solutions of this application more clearly, without, however, limiting the scope of protection of this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as they would normally be understood by a person skilled in the technical field of this application. The terms used here serve only to describe certain embodiments and not to limit this application. The terms "include" and "contain" used in the description, claims, and short description of the drawings of this application, and all variations thereof, are to be understood as non-exclusive inclusion.

[0026] In the description of some embodiments of this application, the technical terms "first" and "second" serve only to distinguish between different elements, but not to indicate or imply any relative significance or to implicitly determine the number of the specified technical features, their specific sequence, or their ranking. In the description of some embodiments of this application, "several" means two or more, unless expressly stated otherwise.

[0027] A reference to a “portion” means that a particular feature, structure, or property described with reference to that embodiment may be included in at least one embodiment of this application. The mention of this term at different points in the specification does not necessarily represent the same embodiment, nor does it represent an independent or alternative embodiment in a mutually exclusive relationship to other embodiments. The person skilled in the art expressly and implicitly understands that the embodiments described herein may be combined with other embodiments.

[0028] In the description of embodiments of this application, the term "and / or" simply denotes a relationship between related elements and represents three possible relationships. For example, "A and / or B" can stand for the following three cases: A alone, both A and B, and B alone. Furthermore, the symbol " / " here generally indicates an "or" relationship between the element preceding the symbol and the element following the symbol.

[0029] In the description of embodiments of this application, the term "several" means two or more (including two). Likewise, "a plurality of groups" means two or more groups (including two groups) and "a plurality of pieces" means two or more pieces (including two pieces).

[0030] In the description of the embodiments of this application, a directional or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "top", "bottom", "before", "after", "left", "right", "vertical", "horizontal", "above", "below", "back", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" is a directional or positional relationship based on the representation in the drawings and serves only to simplify or brevity the description of the embodiments of this application, but does not indicate or imply that the specified device or component is necessarily located in the specified direction or is designed or operated in the specified direction. Therefore, these terms are not to be understood as limiting the embodiments of this application.

[0031] In the description of this application, unless expressly stated and defined otherwise, technical terms such as "assemble," "link," "connect," and "fasten" are to be understood generally in their broadest sense, e.g., as a permanent connection, a detachable connection, or a one-piece configuration; or as a mechanical connection or an electrical connection; or as a direct connection or as an indirect connection realized via an intermediary; or as internal communication between two components or as interaction between two components. A person competent may understand the specific meanings of the terms in some embodiments of this application depending on the specific situations.

[0032] In this application, a battery cell can be a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-ion battery cell, a magnesium-ion battery cell, or similar. The type of battery cell is not restricted. The battery cell can have various shapes, such as cylindrical, flat, cuboid, or other shapes. Regarding packaging, battery cells are generally classified into three types: cylindrical battery cells, prismatic battery cells, and pouch-type battery cells. The type of battery cell is not restricted.

[0033] The battery mentioned in the embodiments of this application is a single physical module containing one or more battery cells to provide a higher voltage and capacity. The battery mentioned in this application may, for example, be a battery module, a battery pack, or the like. A battery typically consists of a housing containing one or more battery cells. The housing prevents liquid or other foreign matter from interfering with the charging or discharging of the battery cells.

[0034] A battery cell contains an electrode assembly and an electrolyte solution. The electrode assembly comprises a positive electrode plate, a negative electrode plate, and a separator. The battery cell primarily functions through the exchange of metal ions between the positive and negative electrode plates. The positive electrode plate contains a positive current collector and a positive active material layer. One surface of the positive current collector is coated with the positive active material layer. A portion of the positive current collector that is not coated with the positive active material layer extends beyond the portion that is coated with it. This portion of the positive current collector that is not coated with the positive active material layer serves as the positive tab.

[0035] Battery performance characteristics include energy density and cycle life. Energy density is the electrical energy released on average per unit volume or mass of the battery. Cycle life is measured by the cumulative number of cycles a rechargeable battery can still maintain a reasonable state of health and is indicated by the number of complete charge / discharge cycles the battery undergoes before it fails or before its capacity begins to decline. Therefore, high energy density and high cycle life can improve the range and lifespan of the electrical device containing the battery. Currently, battery energy density and cycle life are typically improved by increasing the amount of active material and the volume of electrolyte solution in the battery.

[0036] The inventor notes, however, that increasing the amount of active material within the limited space of the battery casing increases the space occupied by the active material and reduces the space available for the electrolyte solution. This leads to a decrease in the amount of electrolyte solution in the battery, which in turn impairs the battery's cycle life. Conversely, increasing the amount of electrolyte solution in the battery leads to a decrease in the battery's energy density and can even result in more side reactions and a shorter battery lifespan. Therefore, it is difficult to achieve both high energy density and high cycle life in a single battery.

[0037] In view of the above problem, one embodiment of this application provides a battery cell, a battery and an electrical device to simultaneously achieve high energy density and high cycle stability of the battery.

[0038] The battery cell, battery and the like disclosed here can be assembled into a power supply system for the electrical device to ensure a long range and a long service life for the electrical device.

[0039] The electrical devices mentioned in this application may include, but are not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric car, an electric vehicle, a ship, a spacecraft, or similar devices. The electric toy may be stationary or mobile, such as a game console, an electric car toy, an electric ship toy, an electric airplane toy, or similar devices. The spacecraft may be an airplane, a rocket, a space shuttle, a spacecraft, or similar devices.

[0040] To simplify the description, a vehicle is used in the following explanations as an example of an electrical device according to an embodiment of this application.

[0041] Fig. Figure 1 is a schematic structural diagram of a vehicle according to some embodiments of this application.

[0042] As in Fig. As shown in Figure 1, a battery 100 is located inside the vehicle 1000. The battery 100 can be located on the underside, front, or rear of the vehicle 1000. The battery 100 can be configured to supply power to the vehicle 1000. For example, the battery 100 can serve as the operating power supply for the vehicle 1000. The vehicle 1000 can also include a control unit 200 and a motor 300. The control unit 200 is configured to control the battery 100 to supply power to the motor 300, for example, to meet the electrical energy requirements for starting, navigating, or driving the vehicle 1000.

[0043] In some embodiments of this application, the battery 100 not only serves as the operating power supply of the vehicle 1000, but can also serve as the drive power supply of the vehicle 1000 in order to provide drive energy for the vehicle 1000 instead of or partially instead of heating oil or natural gas.

[0044] Fig. Figure 2 is a schematic structural diagram of a battery according to some embodiments of this application.

[0045] As in Fig. As shown in Figure 2, the battery 100 comprises a box 10 and a battery cell 20. The box 10 is designed to accommodate the battery cell 20.

[0046] The box 10 is a component designed to house the battery cell 20. The box 10 provides a housing space for the battery cell 20. The box 10 can have different configurations. In some embodiments, the box 10 can comprise a first part 11 and a second part 12. The first part 11 and the second part 12 fit together and overlap each other to define the housing space configured to receive the battery cell 20. The first part 11 and the second part 12 can have different shapes, such as a cuboid or a cylinder. The first part 11 can be a hollow structure open on one side. The second part 12 can also be a hollow structure open on one side. The open side of the second part 12 fits onto and covers the open side of the first part 11 to form the box 10 that provides the housing space.Alternatively, the first part 11 is a hollow body open on one side, and the second part 12 is a plate-shaped structure. The second part 12 fits onto and covers the open side of the first part 11, thus forming the box 10, which provides the storage space. Airtightness between the first part 11 and the second part 12 can be achieved by a sealing element. This sealing element can be a sealing ring, a sealant, or something similar.

[0047] The battery 100 can contain one or more battery cells 20. If a plurality of battery cells 20 are present, the plurality of battery cells 20 can be connected in series, parallel, or series-parallel configurations. Series and parallel connection means a combination of series and parallel connection of the plurality of battery cells 20. The plurality of battery cells 20 is first connected in series, parallel, or series-parallel to form a battery module; subsequently, several battery modules are connected in series, parallel, or series-parallel to form an assembly to be housed in the box 10. Alternatively, all battery cells 20 can be directly connected to each other in series, parallel, or series-parallel configurations, and then the entire assembly of all battery cells 20 is housed in the box 10.

[0048] Fig.Figure 3 is a schematic structure diagram of a battery cell according to some embodiments of this application. Fig. Figure 4 is an exploded view of a battery cell according to some embodiments of this application.

[0049] As in Fig. 3 and Fig. As shown in Figure 4, the battery cell 20 comprises a housing 21, an electrode assembly 22, and an electrolyte solution. A receiving space is formed within the housing 21. The electrode assembly 22 is arranged in the receiving space. The electrolyte solution is located in the receiving space. An electrolyte retention coefficient a and a packing fraction b of the secondary battery satisfy the following relationship: 2 ≤ a / b ≤ 3, and the electrolyte retention coefficient a is given in units of g / Ah.

[0050] The housing 21 is a component that serves to hold the electrode assembly 22. The housing 21 consists of a hollow structure that is open at one end, i.e., a receiving chamber. The housing 21 can have various shapes, e.g., cylindrical or cuboid, without any particular restrictions here. The housing 21 can be made of a variety of materials such as copper, iron, aluminum, steel, or an aluminum alloy, without any particular restrictions here.

[0051] As in Fig. As shown, one or more electrode assemblies 22 can be housed in the casing 21. As shown in Fig. As shown in Figure 4, there is, for example, a large number of electrode assemblies 22. The multiple electrode assemblies 22 are stacked on top of each other.

[0052] The electrode assembly 22 is a component in which electrochemical reactions take place in the battery cell 20 and can be a jelly-roll structure formed by winding or a structure formed by stacking, without this being particularly restricted here.

[0053] In one embodiment of this application, the electrolyte retention coefficient a is a ratio between the amount of retained electrolyte solution and the discharge capacity of the battery cell 20 in the first cycle. The packing ratio b is the ratio of the volume of the electrode assembly 22 in the battery to the volume of the receiving cavity in the housing 21. When the ratio between the electrolyte retention coefficient a and the packing ratio b of the battery cell 20, designated as a / b, is adjusted to fall within the aforementioned suitable range, the battery cell 20 will be endowed with both a high energy density and a relatively high cycle life.

[0054] In some embodiments of this application, the electrolyte retention coefficient a and the packing fraction b of the battery cell 20 satisfy the following relationship: 2.25 ≤ a / b ≤ 2.90.

[0055] In the above explanations, the ratio of the electrolyte retention coefficient a to the packing fraction b of the battery cell 20, denoted as a / b, is adjusted so that it falls within the above suitable range, thereby giving the battery cell 20 both a relatively high energy density and a relatively high cycle stability.

[0056] The ratio of the electrolyte retention coefficient a to the packing fraction b of the battery cell 20, denoted as a / b, can be, for example, 2, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.35, 2.4, 2.45, 2.5, 2.55, 2.6, 2.65, 2.7, 2.75, 2.8, 2.85, 2.9, 2.95 or 3, but is not limited to these values.

[0057] In some embodiments of this application, the electrolyte retention coefficient a lies in a range of values ​​from 1.4 g / Ah to 2.97 g / Ah.

[0058] In the embodiments described above, provided that the electrolyte retention coefficient a and the packing ratio b of the battery cell 20 satisfy the condition 2 ≤ a / b ≤ 3, an electrolyte retention coefficient a falling within the suitable range described above can increase the energy density of the battery cell 20 and simultaneously allow the battery cell 20 to retain a suitable amount of electrolyte solution, thereby improving the cycle stability of the battery cell 20. The capacity retention rate of the battery cell 20 after 1000 cycles at 25 °C is in the range of 80% to 92%. Furthermore, the above setting can improve the storage performance of the battery cell 20 at high temperatures. The capacity retention rate of the battery cell 20 after 90 days of storage at 60 °C is 86% to 96%.

[0059] In some embodiments of this application, the electrolyte retention coefficient a lies in a range of values ​​from 1.8 g / Ah to 2.3 g / Ah.

[0060] In the embodiments described above, provided that the electrolyte retention coefficient a and the packing ratio b of the battery cell 20 satisfy the condition 2 ≤ a / b ≤ 3, an electrolyte retention coefficient a within the aforementioned suitable range can increase the energy density of the battery cell 20 and simultaneously further improve its cycle life. The capacity retention rate of the battery cell 20 after 1000 cycles at 25 °C is in the range of 85% to 92%. Furthermore, the aforementioned setting can further improve the storage performance of the battery cell 20 at high temperatures. The capacity retention rate of the battery cell 20 after 90 days of storage at 60 °C is in the range of 90% to 96%.

[0061] For example, the electrolyte retention coefficient a can be 1.4 g / Ah, 1.41 g / Ah, 1.42 g / Ah, 1.43 g / Ah, 1.44 g / Ah, 1.45 g / Ah, 1.46 g / Ah, 1.47 g / Ah, 1.48 g / Ah, 1.49 g / Ah, 1.50 g / Ah, 1.51 g / Ah, 1.52 g / Ah, 1.53 g / Ah, 1.54 g / Ah, 1.55 g / Ah, 1.56 g / Ah, 1.57 g / Ah, 1.58 g / Ah, 1.59 g / Ah, 1.60 g / Ah, 1.61 g / Ah, but is not limited to these values.1.62g / Ah, 1.63g / Ah, 1.64g / Ah, 1.65g / Ah, 1.66g / Ah, 1.67g / Ah, 1.68g / Ah, 1.69g / Ah, 1.70g / Ah, 1.71g / Ah, 1.72g / Ah, 1.73 g / Ah, 1.74 g / Ah, 1.75 g / Ah, 1.76 g / Ah, 1.77 g / Ah, 1.78 g / Ah, 1.79 g / Ah, 1.80 g / Ah, 1.81 g / Ah, 1.82 g / Ah, 1.83 g / Ah, 1.84 g / Ah, 1.85g / Ah, 1.86 g / Ah, 1.87 g / Ah, 1.88 g / Ah, or 1.90 g / Ah to 2.0 g / Ah, 2.01 g / Ah, 2.02 g / Ah, 2.03 g / Ah, 2.04 g / Ah to 2.19 g / Ah, 2.20 g / Ah, 2.21 g / Ah to 2.29g / Ah, 2.30g / Ah, 2.31g / Ah to 2.69g / Ah, 2.70g / Ah, 2.71g / Ah, 2.72g / Ah, 2.73g / Ah, 2.74g / Ah, 2.75g / Ah, 2.76g / Ah, 2.77 g / Ah, 2.78 g / Ah, 2.79 g / Ah, 2.80 g / Ah, 2.81 g / Ah, 2.82 g / Ah, 2.83 g / Ah, 2.84 g / Ah, 2.85 g / Ah, 2.86 g / Ah, 2.87 g / Ah, 2.88 g / Ah, 2.89 g / Ah, 2.90 g / Ah, 2.91 g / Ah, 2.92 g / Ah, 2.93 g / Ah, 2.94 g / Ah, 2.95 g / Ah, 2.96 g / Ah or 2.97 g / Ah. However, it is not limited to these values.

[0062] In some embodiments of this application, the packing fraction b of the battery cell 20 lies in a value range of 80% to 99%.

[0063] In the above embodiments, provided that the electrolyte retention coefficient a and the packing fraction b of the battery cell 20 satisfy the conditions 2 ≤ a / b ≤ 3, the packing fraction b of the battery cell 20, which falls within the above-mentioned suitable range, can improve the cycle stability of the battery cell 20 and simultaneously increase the energy density of the battery cell 20. The gravimetric energy density of the battery cell 20 lies in the range of 190 Wh / g to 213 Wh / g.

[0064] In some embodiments of this application, the packing fraction b of the battery cell 20 lies in a value range of 85% to 95%.

[0065] In the above embodiments, provided that the electrolyte retention coefficient a and the packing fraction b of the battery cell 20 satisfy the conditions 2 ≤ a / b ≤ 3, the packing fraction b of the battery cell 20, which falls within the above-mentioned suitable range, can improve the cycle stability of the battery cell 20 and simultaneously increase the energy density of the battery cell 20. The gravimetric energy density of the battery cell 20 lies in the range of 196 Wh / g to 213 Wh / g.

[0066] The packing fraction b of the battery cell 20 can be, for example, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99%, but is not limited to these.

[0067] In some embodiments of this application, the electrode assembly 22 comprises a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate comprises a positive current collector and a positive active material layer arranged on at least one surface of the positive current collector. The positive active material layer contains a positive active material. The negative electrode plate comprises a negative current collector and a negative active material layer arranged on at least one surface of the negative current collector. The negative active material layer contains a negative active material. The separator is arranged between the positive electrode plate and the negative electrode plate.The positive active material is at least one of the following: lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, a lithium-rich positive active material, or a ternary positive active material. The negative active material is at least one selected from a carbon-containing negative active material, a silicon-containing negative active material, an alloyed negative active material, a lithium-containing negative active material, or a tin-containing negative active material.

[0068] The positive current collector can consist of a metal foil, a porous metal sheet, or another material. For example, the positive current collector can be a foil or a porous sheet made of a metal such as copper, nickel, titanium, or silver, or an alloy thereof, but is not limited to such materials. In some specific embodiments of this application, the positive current collector is an aluminum foil.

[0069] The negative current collector can consist of a metal foil, a porous metal sheet, or another material. For example, the negative current collector can be a foil or a porous sheet made of metal such as copper, nickel, titanium, or iron, or an alloy thereof, but is not limited to such materials. In some specific embodiments of this application, the negative current collector is a copper foil.

[0070] In such embodiments, the appropriate selection of the positive active material and the negative active material can improve the energy density and the cycle stability of the battery cell 20.

[0071] In some embodiments of this application, the ternary positive active material is represented by the following chemical formula: LiNi xC O yN -M ı - x - y - zO2 , where N is selected from Mn or Al, M is at least one of Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti, 0 ≤ x < 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1 and x + y + z ≤ 1. The ternary positive active material represented by the chemical formula above can further increase the energy density of battery cell 20.

[0072] In some embodiments of this application, the lithium-rich positive active material is represented by the following chemical formula: Li2MnO3 · (1-c)LiAO2, where A is at least one element selected from Ni, Co or Mn, and 0 ≤ c < 1. The lithium-rich positive active material represented by the above chemical formula can also further increase the energy density of the battery cell 20.

[0073] In some embodiments of this application, the positive active material layer may also contain a conductive agent and a binder. The types of conductive agent and binder in the positive active material are not limited in this embodiment and can be selected according to actual needs.

[0074] The conductive material can be, for example, one or more of the following substances: graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers, but are not limited to these. The binder can be one or more of the following materials: styrene-butadiene rubber (SBR), water-based acrylic resin, carboxymethylcellulose (CMC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), poly(vinylidene fluoride-co-tetrafluoroethylene-co-propylene), poly(vinylidene fluoride-co-hexafluoropropylene-co-tetrafluoroethylene), poly(tetrafluoroethylene-co-hexafluoropropylene), fluorinated acrylic resin, or polyvinyl alcohol (PVA).

[0075] The positive electrode plate of this application is produced by the following process: mixing the positive active material, the conductive agent and the binder in a specific mass ratio in a suitable amount of NMP solvent and stirring well to form a homogeneous positive electrode paste; applying the positive electrode paste to a surface of the positive current collector aluminum foil and performing steps such as drying and cold pressing to obtain a positive electrode plate.

[0076] In some embodiments of this application, the negatively active material may comprise at least one of the following materials: natural graphite, synthetic graphite, mesocarbon microbeads (MCMBs), hard carbon, soft carbon, silicon, a silicon-carbon composite, a Li-Sn alloy, a Li-Sn-O alloy, Sn, SnO, SnO2, spinel-structured lithiated TiO2-Li4Ti5O 12or a Li-Al alloy.

[0077] In some embodiments of this application, the negative active material layer may also contain a conductive agent and a binder. The types of conductive agent and binder in the negative active material layer are not particularly limited here and can be selected according to the actual requirements.

[0078] The conductive material can be, for example, one or more of the following substances: graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers, but this list is not limited to these. The binder can be one or more of the following substances: styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), water-based acrylic resin, or carboxymethylcellulose (CMC).

[0079] In one embodiment of this application, the negative electrode plate is produced by the following method: mixing the negative active material, the conductive agent, and the binder in a specific mass ratio in a suitable quantity of deionized water and stirring well to form a homogeneous negative electrode paste; applying the negative electrode paste to a surface of the negative current collector copper foil and performing steps such as drying and cold pressing to obtain a negative electrode plate.

[0080] Furthermore, the electrode assembly 22 comprises a positive tab 221 and a negative tab 222. The positive tab 221 can be a part that is not coated with the positive active material layer on the positive electrode plate, and the negative tab 222 can be a part that is not coated with the negative active material layer on the negative electrode plate.

[0081] In this embodiment of the present application, the type of separator is not specifically limited and can be any known porous separator that is chemically and mechanically very stable. In some embodiments, the separator material can consist of glass fiber, nonwoven fabric, polyethylene, polypropylene, or polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film. If the separator is a multi-layer composite film, the materials in the different layers can be identical or different.

[0082] In relation to Fig.4 In some embodiments of this application, the battery cell 20 may also include an end cap 23. The end cap 23 is a component that closes the opening of the housing 21 to isolate the internal environment from the external environment of the battery cell 20. The end cap 23 fits onto and covers the opening of the housing 21. The end cap 23 and the housing 21 together form an airtight space designed to accommodate the electrode assembly 22, the electrolyte solution, and other components. The shape of the end cap 23 can be adapted to the shape of the housing 21. For example, the housing 21 is cuboid, and the end cap 23 is a rectangular, plate-shaped structure that fits into the housing 21. Another example: The housing 21 is cylindrical, and the end cap 23 is a circular, plate-shaped structure that fits into the housing 21.The end cap 23 can be made of a variety of materials such as copper, iron, aluminum, steel, or an aluminum alloy. The material of the end cap 23 can be identical to or different from the material of the housing 21.

[0083] An electrode terminal can be attached to the end cap 23. The electrode terminal is configured to be electrically connected to the electrode assembly 22 to deliver the electrical energy of the battery cell 20. The electrode terminal can comprise a positive electrode terminal 231 and a negative electrode terminal 232. The positive electrode terminal 231 is configured to be electrically connected to the positive tab 221. The negative electrode terminal 232 is configured to be electrically connected to the negative tab 222. The positive electrode terminal 231 can be connected directly or indirectly to the positive tab 221, and the negative electrode terminal 232 can be connected directly or indirectly to the negative tab 222.

[0084] In some embodiments of this application, the electrolyte solution contains an organic solvent and an electrolyte salt, and the organic solvent is at least one compound selected from an ester or ether compound.

[0085] In the above embodiments, the organic solvent, which is selected from at least one ester compound or one ether compound, improves the cycle stability of the battery cell 20.

[0086] In some embodiments of this application, the ester compound is at least one of the following compounds: dimethyl carbonate, diethyl carbonate, propylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, ethyl formate, ethyl acetate, or ethylene carbonate. The ester compound, which is one or more of the above-mentioned ester compounds, can further improve the cycle stability of the battery cell 20.

[0087] In some embodiments of this application, the ether compound is at least one of tetrahydrofuran, 2-methylfuran, 3-methylfuran, 2-ethylfuran, 2-propylfuran, 2-butylfuran, 2,3-dimethylfuran, 2,4-dimethylfuran, 2,5-dimethylfuran, pyran, 2-methylpyran, 3-methylpyran, 4-methylpyran, benzofuran, or 2-(2-nitrovinyl)furan. The ether compound, which is one or more of the aforementioned ether compounds, can further improve the cycle stability of the battery cell 20.

[0088] In some embodiments of this application, the electrolyte solution also contains an additive. The additive may, for example, consist of at least one of the following substances: ethylene carbonate, ethylene sulfate, lithium difluoro(oxalato)borate, lithium difluorophosphate, lithium tetrafluoroborate, 1,3-propanesultone, lithium trifluoromethanesulfonate, or lithium bis(oxalato)borate.

[0089] In some embodiments of this application, the concentration of the electrolyte salt in the electrolyte solution is 0.6 mol / L to 2.0 mol / L. When the concentration of the electrolyte salt in the electrolyte solution falls within the above-mentioned suitable range, the concentration of the electrolyte salt in the electrolyte solution improves the ionic conductivity of the electrolyte solution and the mobility of the metal ions in the electrolyte solution, thereby improving the cycle stability of the battery cell 20.

[0090] The concentration of the electrolyte salt in the electrolyte solution can be, for example, 0.6 M, 0.7 M, 0.8 M, 0.9 M, 1.0 M, 1.1 M, 1.2 M, 1.3 M, 1.4 M, 1.5 M, 1.6 M, 1.7 M, 1.8 M, 1.9 M or 2.0 M, but is not limited to these values.

[0091] In the above embodiments, the electrolyte salt can be a lithium salt. The lithium salt can be, for example, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10, LiPF6, LiFSI, LiCF3SO3, LiCF3CO2, LiC4BO8, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, (C2F5SO2)2NLi, (SO2F)2NLi, or (CF3SO2)3CLi.

[0092] In some embodiments of this application, the electrolyte salt is at least one selected from LiPF6 or LiFSI. The electrolyte salt selected from the aforementioned lithium salts can improve the high-temperature storage performance of the battery cell 20.

[0093] One embodiment of this application provides a battery. The battery contains the battery cell described in one of the embodiments above. Since the battery contains the battery cell disclosed in one of the embodiments above, the battery achieves the technical effects of the battery cell, which will not be discussed in detail here.

[0094] One embodiment of this application provides an electrical device. The electrical device contains the battery described in the embodiment above.

[0095] The following embodiments are more detailed descriptions of the subject matter disclosed herein. These embodiments serve only for illustration, as a person skilled in the art can, of course, make various modifications and changes to them without deviating from the information contained herein. Unless otherwise specified, all fractions, percentages, and ratios mentioned in the following embodiments are weight values. All reagents used in the embodiments are commercially available or can be synthesized by conventional methods and can be used directly without further processing. All instruments used in the embodiments are commercially available. embodiment 1Preparing a positive electrode plate

[0096] Mixing LiNi 0.8 Co 0.1 Mn 0.1 O2 as the positive active material, Super P as the conductive agent, and polyvinylidene fluoride (PVDF) as the binder in a mass ratio of 95:3:2 in a suitable amount of N-methylpyrrolidone (NMP) solvent, and thoroughly stirred to form a homogeneous positive electrode paste with a solids content of 50 wt%. The positive electrode paste is applied to the surface of a current collector aluminum foil, dried at 85 °C, cold-pressed, edge-trimmed, sheared and cut, and the resulting plate is dried in an 85 °C vacuum environment for 4 hours to obtain a positive electrode plate. Preparing a negative electrode plate

[0097] Graphite as the negative active material, Super P as the conductive agent, CMC as a thickener, and styrene-butadiene rubber (SBR) as a binder are mixed in a mass ratio of 92:3:2.5:2.5 in deionized water, stirring thoroughly to form a homogeneous negative electrode paste with a solids content of 30 wt%. The negative electrode paste is applied to the surface of a copper current collector foil and dried at 85 °C. The plate is then cold-pressed, trimmed, sheared, and cut at the edges, and subsequently dried for 12 hours in a vacuum environment at 120 °C to obtain a negative electrode plate. Preparing a separator

[0098] Using a 16 µm thick polyethylene (PE) film as a separator. Preparing an electrolyte solution

[0099] Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a ratio of 3:7 w% / w% in an argon-filled glovebox (where the water content is below 10 ppm and the oxygen content is below 1 ppm), followed by the addition of 2% vinylene carbonate. After thorough stirring, 1 mol of LiFP6 is slowly added to the resulting solution, causing the LiFP6 to dissolve completely and forming an electrolyte solution. Preparing a battery cell

[0100] Stack the positive electrode plate, separator, and negative electrode plate sequentially and wind the stacked structure to form an electrode assembly. Place the electrode assembly in an outer packaging, inject the prepared electrolyte solution, and proceed with steps such as packaging, setting, chemical formation, and aging to produce a battery cell. Embodiments 2 to 10 and comparative embodiments 1 to 2

[0101] The manufacturing process is similar to that of embodiment 1, except that the electrolyte retention coefficient and the packing ratio are adjusted as described in Table 1. Test part 1) Testing the capacity of the battery cell

[0102] The battery is stored at 25 °C for 60 minutes and then charged at a current of 1 C until the voltage reaches 4.25 V. It is then charged at a constant voltage until the current drops to 0.05 C. After this, the battery is left to stand for 30 minutes and then discharged at a current of 1 C until the voltage reaches 2.8 V. The battery is left to stand for another 30 minutes, and the discharge capacity D1 is recorded. 2) Testing the electrolyte retention rate

[0103] Weighing the battery cell to be disassembled and recording the weight as M1. Disassembling the battery cell, pouring out the free electrolyte solution, adding dimethyl carbonate (DMC) to the casing, extracting the essence three times, pouring out the remaining DMC liquid, placing the components, such as the electrode assembly and the casing, in an oven to thoroughly remove DMC, and subsequently weighing the resulting product to obtain a weight designated as M2. Calculating the electrolyte retention quantity as follows: Electrolyte retention quantity = M1 - M2, and calculating the electrolyte retention coefficient a as follows: a = (M1 - M2) / D1. 3) Examination of the battery cell's packing content

[0104] Immersion of the electrode assembly in water and measurement of its volume V1 using a water displacement method based on Archimedes' principle. Direct calculation of the volume of a regular casing, denoted V2, or calculation of the volume of an irregular casing by determining the amount of water the casing displaces. Calculation of the packing density b of the battery cell as follows: b = V1 / V2. 4) Testing the cycle stability of the battery cell

[0105] A battery cell is charged at a constant current of 0.5C in an environment of 25°C until the voltage reaches 4.25 V, and then charged at a constant voltage of 4.25 V until the current drops to 0.05C. The battery cell is then discharged at a constant current of 1C until the voltage drops to 2.8 V. The discharge capacity at this point is recorded as C1. The discharge capacity of the battery cell at the end of the 1000 cycle is recorded as C2. The capacity retention rate at the end of the 1000 cycle is calculated as follows: Capacity Retention Rate (%) = (C2 / C1) × 100%. The test results are listed in Table 1. 5) Testing the high-temperature storage performance of the battery cell

[0106] Charge a battery cell at a current of 1C in an environment of 25°C until the voltage reaches 4.25 V, then charge the battery cell at a constant voltage until the current drops to 0.05C. Allow it to stand for 30 minutes, then discharge the battery cell at a current of 1C until the voltage drops to 2.8 V. Record the discharge capacity at this point as C3. Charge the battery cell at a current of 1C until the voltage reaches 4.25 V, then charge the battery cell at a constant voltage until the current drops to 0.05C, and then store the battery cell in a 60°C thermostat for 90 days. Remove the battery cell and wait until the surface temperature of the battery cell is again 25°C, then discharge the battery cell at a current of 1C until the voltage reaches 2.8 V.The battery cell was left to stand for 30 minutes, then charged at a current of 1C until the voltage reached 4.25 V, and subsequently charged at a constant voltage until the current dropped to 0.05C. The battery cell was then left to stand for 30 minutes and subsequently discharged at a current of 1C until the voltage dropped to 2.8 V, with the discharge capacity recorded as C4. The reversible capacity retention rate of the battery cell after 90 days of storage at 60 °C was calculated as follows: reversible capacity retention rate (%) = (C4 / C3) × 100%. The test results are shown in Table 1. 6) Testing the energy density of the battery cell

[0107] The battery cell is weighed and the weight recorded in meters. The discharge voltage plateau of the battery cell is denoted as P, and the gravimetric energy density of the battery cell is calculated as follows: gravimetric energy density (Wh / g) = D1 × P / m. The test results are listed in Table 1. Table 1 Serial number Electrolyte retention coefficient a(g / Ah) Package portion b away Capacity maintenance rate (25 °C) Maintaining storage capacity at high temperatures (60 °C) Gravimetric energy density (WhIg) Design 1 1,80 80 % 3,00 90,3 % 95,40 % 212,8 Version 2 1,76 88 % 2,00 86,3 % 91,2 0% 196,3 embodiment 3 2,70 90 % 3,00 85,3 % 90,70 % 195,4 Design 4 2,30 88 % 2,61 90,5 % 94,50 % 210,7 Design 5 2,00 85 % 2,35 91,0 % 95,30 % 212 Design 6 2,00 95 % 2,11 90,1 % 94,80 % 211,9 Model 7 2,83 99 % 2,86 89,5 % 93,30 % 209,5 Design 8 2,20 83 % 2,65 89,9 % 93,00 % 210 Design 9 1,8 90 % 2,00 85,7 % 90,20 % 197,4 Design 10 2,03 97 % 2,09 91,2 % 93,50 % 210,9 Comparative version 1 1,5 80 % 1,875 67,2 % 77,20 % 176,2 Comparative version 2 2,81 93 % 3,02 73,2 % 82,40 % 180,3

[0108] As can be seen from the comparison results of embodiments 1 to 10 compared with the comparative embodiments 1 to 2 in Table 1, the battery cell in an embodiment of this application is disclosed if the electrolyte retention coefficient a and the packing ratio b of the battery cell meet: 2 ≤ a / b ≤ 3, the battery cell is equipped with both a high energy density and a relatively high cycle performance.

[0109] Finally, it should be noted that the foregoing embodiments serve only to describe the technical solutions of this application, not to limit it. Although this application has been described in detail with reference to the foregoing embodiments, it is clear to those skilled in the art that the technical solutions described in the foregoing embodiments may be modified, or that some or all of the technical features of the technical solutions may be replaced by equivalent substitutions. Such modifications and equivalent substitutions fall within the scope of the claims and the present description, without the essence of the corresponding technical solutions differing from the scope of the technical solutions of the embodiments of the present application.In particular, provided there is no structural conflict, various technical features mentioned in different embodiments may be combined in any way. This application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions that fall within the scope of the claims. REFERENCE MARK LIST

[0110] List of reference symbols: 1000 vehicles; 100 batteries; 200 control unit; 300 engine; 10 boxes; 11 Part One; 12 Part Two; 20 battery cells; 21 cases; 22 Electrode assembly; 221 positive tab; 222 negative tab; 23 End cap; 231 positive electrode connection; 232 negative electrode connection.

Claims

[1] A battery cell (20) comprising: a housing in which a recording chamber is formed; an electrode assembly arranged in the recording space; and an electrolyte solution arranged in the receiving chamber, wherein an electrolyte retention coefficient a and a packing fraction b of the battery cell (20) satisfy the following relationship: 2 ≤ a / b ≤ 3, and the electrolyte retention coefficient a is given in units of g / Ah. [2] Battery cell (20) according to claim 1, wherein the electrolyte retention coefficient a and the packing ratio b of the battery cell (20) satisfy the following relationship: 2.25 ≤ a / b ≤ 2.

90. [3] Battery cell (20) according to claim 1 or 2, wherein the electrolyte retention coefficient a falls within a range of 1.4 g / Ah to 2.97 g / Ah. [4] Battery cell (20) according to one of claims 1 to 3, wherein the electrolyte retention coefficient a falls within a range of 1.8 g / Ah to 2.3 g / Ah. [5] Battery cell (20) according to one of claims 1 to 4, wherein the packing fraction b of the battery cell (20) is in a value range of 80% to 99%. [6] Battery cell (20) according to any one of claims 1 to 5, wherein the packing fraction b of the battery cell (20) is in a range of 85% to 95%. [7] Battery cell (20) according to any one of claims 1 to 6, wherein the electrode assembly comprises: a positive electrode plate comprising a positive current collector and a positive active material layer arranged on at least one surface of the positive current collector, wherein the positive active material layer comprises a positive active material; a negative electrode plate comprising a negative current collector and a negative active material layer arranged on at least one surface of the negative current collector, wherein the negative active material layer comprises a negative active material; and a separator positioned between the positive electrode plate and the negative electrode plate, where: the positive active material is at least one of the following: lithium cobalt oxide, lithium iron phosphate as a positive active material, lithium manganese oxide, lithium-rich positive active material, or a ternary positive active material; and the negative active material is at least one selected from a carbon-containing negative active material, a silicon-containing negative active material, an alloyed negative active material, a lithium-containing negative active material, or a tin-containing negative active material. [8] Battery cell (20) according to claim 7, wherein the ternary positive active material is represented by the following chemical formula: LiNi x Co y N z M 1-x-y-z O2, whereby: N is selected from Mn or Al M is at least one selected from Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti, 0≤x<1, 0≤y<1, 0≤z<1, and x+y+z≤1. [9] Battery cell (20) according to claim 7 or 8, wherein the lithium-rich positive active material is represented by the following chemical formula: Li2MnO3-(1-c)LiAO2, where A is at least one selected from Ni, Co or Mn; and 0 ≤ c < 1. [10] Battery cell (20) according to any one of claims 1 to 9, wherein the electrolyte solution comprises an organic solvent and an electrolyte salt and the organic solvent is at least one selected from an ester compound or an ether compound. [11] Battery cell (20) according to claim 10, wherein the ester compound is at least one selected from dimethyl carbonate, diethyl carbonate, propylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, ethyl formate, ethyl acetate or ethylene carbonate. [12] Battery cell (20) according to claim 10, wherein the ether compound is at least one selected from tetrahydrofuran, 2-methylfuran, 3-methylfuran, 2-ethylfuran, 2-propylfuran, 2-butylfuran, 2,3-dimethylfuran, 2,4-dimethylfuran, 2,5-dimethylfuran, pyran, 2-methylpyran, 3-methylpyran, 4-methylpyran, benzofuran or 2-(2-nitrovinyl)furan. [13] Battery cell (20) according to one of claims 10 to 12, wherein the concentration of the electrolyte salt in the electrolyte solution is 0.6 mol / L to 2.0 mol / L. [14] Battery cell (20) according to any one of claims 10 to 13, wherein the electrolyte salt is at least one selected from lithium hexafluorophosphate or lithium bis(fluorosulfonyl)imide. [15] Battery comprising the battery cell (20) according to any one of claims 1 to 14. [16] An electrical device comprising the battery according to claim 15.

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