Battery monomer, battery device and electric device

Abstract

The invention discloses a battery monomer, a battery device and a power utilization device. The battery monomer comprises an electrolyte, the electrolyte comprises an organic solvent and an additive, the organic solvent comprises an isoxazole compound, and the additive comprises nitrate and fluoride. According to the battery cell provided by the embodiment of the invention, the low-temperature charging capability of the battery cell can be improved.

Description

Technical Field

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

[0002] Batteries are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric car toys, electric toy ships, electric toy airplanes, and power tools.

[0003] In the development of battery cells, improving the fast charging performance of battery cells is one of the urgent problems to be solved. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a battery cell, a battery device, and an electrical device.

[0005] In a first aspect, embodiments of this application provide a battery cell including an electrolyte, wherein the electrolyte includes an organic solvent and additives, the organic solvent including isoxazole compounds, and the additives including nitrates and fluorides.

[0006] In this embodiment, the synergistic effect of isoxazole compounds, nitrates, and fluorides can result in an electrolyte with low viscosity, especially at low temperatures, and a high ionic conductivity, enabling the battery cell to have good fast charging capability. At the same time, the electrolyte and negative electrode active material have good stability, enabling the battery cell to have high capacity retention.

[0007] In some embodiments, the isoxazole compounds include compounds represented by Formula 1:

[0008]

[0009] R1, R2, and R3 each independently include hydrogen atoms and unsubstituted or heteroatom-substituted alkyl groups with 1-10 carbon atoms.

[0010] In some embodiments, the heteroatom includes one or more of halogen atoms, N, P, S, O, and B.

[0011] In some embodiments, the isoxazole compounds include one or more of the following compounds:

[0012]

[0013] In some embodiments, the volume content of the isoxazole compound is 10% to 90% based on the total volume of the organic solvent.

[0014] In some embodiments, the nitrate includes one or more of lithium nitrate, sodium nitrate, potassium nitrate, copper nitrate, zinc nitrate, magnesium nitrate, and aluminum nitrate.

[0015] In some embodiments, the nitrate content in the electrolyte is 0.1% to 5% by mass.

[0016] In some embodiments, the fluoride includes one or more of lithium fluoride, sodium fluoride, potassium fluoride, copper fluoride, zinc fluoride, magnesium fluoride, and aluminum fluoride.

[0017] In some embodiments, the fluoride content in the electrolyte is 0.1% to 5% by mass.

[0018] In some embodiments, the mass ratio of the nitrate to the fluoride is 1:(0.02-50).

[0019] In some embodiments, the mass ratio of the isoxazole compound to the nitrate is (10-90):1.

[0020] In some embodiments, the organic solvent further includes carbonates, wherein the volume content of the carbonates is 10% to 90% based on the total volume of the organic solvent.

[0021] Secondly, embodiments of this application provide a battery device, including a single battery cell from the first aspect of this application.

[0022] Thirdly, embodiments of this application provide an electrical device, including a battery cell from the first aspect of this application or a battery device from the second aspect of this application. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0024] Figure 1 The diagram shows the structure of a vehicle provided in some embodiments of this application.

[0025] Figure 2 This is an exploded schematic diagram of a battery provided for some embodiments of this application.

[0026] Figure 3 for Figure 2 The diagram shows an exploded view of the battery module.

[0027] The accompanying drawings are not necessarily drawn to scale.

[0028] The reference numerals in the attached drawings are explained as follows: 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 5c. Reception space; 6. Battery module; 7. Battery cell. Detailed Implementation

[0029] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the battery cell, battery device, and power-consuming device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0030] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints 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 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0031] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0032] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0033] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0034] Unless otherwise specified, in this application, the terms "first," "second," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0035] In this application, the terms "multiple" or "various" refer to two or more kinds.

[0036] In the description of the embodiments of this application, unless otherwise specified, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0037] Unless otherwise stated, the terms used in this application have the common meanings as commonly understood by those skilled in the art.

[0038] Unless otherwise stated, the values ​​of the parameters mentioned in this application can be determined using various testing methods commonly used in the art, for example, according to the testing methods given in the embodiments of this application. Unless otherwise stated, the test temperature for each parameter is 25°C.

[0039] The battery device mentioned in the embodiments of this application can be a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application can include battery cells, battery modules, or battery packs.

[0040] A single battery cell is the smallest unit that makes up a battery, and it can independently perform the functions of charging and discharging. When there are multiple battery cells, they are connected in series, parallel, or mixed connections through a busbar.

[0041] In some embodiments, the battery device may be a battery module; when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0042] In some embodiments, the battery device may be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0043] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0044] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0045] The technical solutions described in the embodiments of this application are applicable to battery devices and electrical devices that use battery devices.

[0046] Battery devices can be used as the power source for electrical devices or as energy storage units for electrical devices. Electrical devices can be, but are not limited to, mobile devices (such as mobile phones, tablets, laptops, etc.), vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0047] Electrical devices can choose the type of battery device according to their usage needs, such as individual battery cells, battery modules, or battery packs.

[0048] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0049] Figure 1 The diagram shows the structure of a vehicle provided in some embodiments of this application.

[0050] like Figure 1 As shown, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0051] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0052] In some embodiments, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0053] Figure 2 This is a schematic diagram of a battery explosion provided for some embodiments of this application. For example... Figure 2 As shown, the battery device 2 includes a housing 5 and battery cells (not shown), with the battery cells housed within the housing 5.

[0054] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0055] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0056] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0057] In battery device 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells are connected in both series and parallel configurations. Multiple battery cells can be directly connected in series, in parallel, or in a mixed configuration, and then the whole assembly of multiple battery cells is housed in housing 5. Alternatively, multiple battery cells can first be connected in series, in parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, in parallel, or in a mixed configuration to form a whole assembly, which is then housed in housing 5.

[0058] Figure 3 for Figure 2 The diagram shows an exploded view of the battery module.

[0059] like Figure 3 As shown, in some embodiments, there are multiple battery cells 7, which are first connected in series, parallel, or mixed to form a battery module 6. The multiple battery modules 6 are then connected in series, parallel, or mixed to form a whole and housed in a casing.

[0060] Multiple battery cells 7 in battery module 6 can be electrically connected through a busbar component to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6.

[0061] The battery cells mentioned in the embodiments of this application may include lithium-ion battery cells or sodium-ion battery cells.

[0062] The battery cell includes an electrode assembly. The electrode assembly can be a wound structure or a stacked structure, and the embodiments of this application are not limited to this.

[0063] Electrode assemblies generally include a positive electrode, a negative electrode, and a separator.

[0064] The battery cell also includes an electrolyte. In some embodiments, the electrolyte is a liquid electrolyte.

[0065] The fast-charging capability of a battery cell relies heavily on high electrolyte conductivity. Electrolyte conductivity is closely related to its viscosity; lower electrolyte viscosity facilitates the rapid transport of active ions, resulting in higher conductivity. Conversely, high electrolyte solvent viscosity hinders conductivity improvement, especially at low temperatures. The solidification of organic solvents increases electrolyte viscosity, leading to decreased conductivity and poorer fast-charging performance of the battery cell.

[0066] In view of this, the battery cell provided in this application embodiment adjusts the electrolyte design so that the electrolyte can have a lower viscosity at low temperatures, thereby improving the conductivity of the electrolyte and thus improving the fast charging capability of the battery cell.

[0067] Electrolyte

[0068] In some implementations, the electrolyte includes electrolyte salts, organic solvents, and additives; the organic solvents include isoxazole compounds, and the additives include nitrates and fluorides.

[0069] In this embodiment, isoxazole compounds may include isoxazole and isoxazole derivatives. Using isoxazole compounds as solvents for the electrolyte is beneficial because these compounds have low viscosity, which reduces the viscosity of the electrolyte and gives it higher ionic conductivity. Simultaneously, isoxazole compounds have low melting points and do not easily solidify at low temperatures, allowing the electrolyte to maintain a low viscosity even at low temperatures, thereby significantly improving the ionic conductivity of the electrolyte at low temperatures.

[0070] Because isoxazole compounds are prone to solvent co-intercalation in battery cells, which disrupts the structural stability of the negative electrode active material and affects its capacity, this application incorporates nitrates as additives in the electrolyte. The addition of nitrates can form a nitrogen-rich solid electrolyte interphase (SEI) film at the negative electrode interface, thereby suppressing the solvent co-intercalation problem of isoxazole compounds and maintaining the structural stability of the negative electrode active material and the capacity utilization of the battery cell's negative electrode. Furthermore, this application incorporates fluorides as co-solvents for nitrates in the electrolyte. Fluorides can form chelates with nitrates, promoting their dissolution in the electrolyte. Additionally, fluorides can participate in the formation of the SEI film, further suppressing the solvent co-intercalation problem of isoxazole compounds and maintaining the structural stability of the negative electrode active material and the capacity utilization of the battery cell's negative electrode.

[0071] In this embodiment, the synergistic effect of isoxazole compounds, nitrates, and fluorides can result in an electrolyte with low viscosity, especially at low temperatures, and a high ionic conductivity, enabling the battery cell to have good fast charging capability. At the same time, the electrolyte and negative electrode active material have good stability, enabling the battery cell to have high capacity retention.

[0072] In some embodiments, isoxazole compounds may include the compound shown in Formula 1:

[0073]

[0074] R1, R2, and R3 each independently include hydrogen atoms and unsubstituted or heteroatom-substituted alkyl groups with 1-10 carbon atoms.

[0075] In some embodiments, heteroatoms may include one or more of halogen atoms, N, P, S, O, and B.

[0076] For example, isoxazole compounds may include one or more of the following compounds:

[0077]

[0078] In some embodiments, the volume content of the isoxazole compound can be from 10% to 90% based on the total volume of the organic solvent. Exemplarily, the volume content of the isoxazole compound can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or any range of the foregoing values, based on the total volume of the organic solvent. Optionally, the volume content of the isoxazole compound can be from 50% to 90% based on the total volume of the organic solvent.

[0079] Limiting the content of isoxazole compounds in the organic solvent to the above range can result in a lower viscosity of the electrolyte, which is beneficial to improving the ionic conductivity of the electrolyte and thus enhancing the fast charging capability of the battery cell.

[0080] In some embodiments, the nitrate may include one or more of lithium nitrate, sodium nitrate, potassium nitrate, copper nitrate, zinc nitrate, magnesium nitrate, and aluminum nitrate.

[0081] In some embodiments, the mass content of nitrate in the electrolyte can be from 0.1% to 5%. Exemplarily, the mass content of nitrate in the electrolyte can be 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, or any range of the above values. Optionally, the mass content of nitrate in the electrolyte can be from 0.5% to 4.5%.

[0082] In some embodiments, the fluoride may include one or more of lithium fluoride, sodium fluoride, potassium fluoride, copper fluoride, zinc fluoride, magnesium fluoride, and aluminum fluoride.

[0083] In some embodiments, the mass content of fluoride in the electrolyte can be from 0.1% to 5%. Exemplarily, the mass content of fluoride in the electrolyte can be 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, or any range of the above values. Optionally, the mass content of fluoride in the electrolyte can be from 0.5% to 4%.

[0084] In some embodiments, the mass ratio of nitrate to fluoride can be 1:(0.02-50), or optionally 1:(0.2-10).

[0085] In some embodiments, the mass ratio of isoxazole compounds to nitrates can be (10-90):1.

[0086] Limiting the mass ratio of nitrate to fluoride and nitrate to isoxazole compounds to the above range is beneficial to further improve the solubility of nitrate in the electrolyte, and at the same time, it is beneficial to form a stable nitrogen-containing SEI film and suppress the solvent co-intercalation problem of isoxazole compounds.

[0087] In some embodiments, the organic solvent may further include carbonates, such as one or more of cyclic carbonates and chain carbonates; optionally, the carbonates may include both cyclic and chain carbonates. Chain carbonates may include low-viscosity polar chain carbonates, aliphatic branched carbonates, etc. The addition of carbonates can promote lithium salt dissolution and improve the dissolution effect of lithium salts in the electrolyte.

[0088] For example, the carbonate may include, but is not limited to, one or more of ethylene carbonate (EC), propylene carbonate (PC), butene carbonate, ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), and fluoroethylene carbonate (FEC).

[0089] In some embodiments, the volume percentage of carbonate in the organic solvent can be from 10% to 90%, optionally from 10% to 50%.

[0090] In some embodiments, the organic solvent may also include one or more of esters, ethers, sulfones, nitriles, etc., other than the carbonates described above. Esters may include, but are not limited to, one or more of phosphate esters, carboxylic esters, sulfate esters, sulfonates, etc.

[0091] As examples, organic solvents may include methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), diethyl sulfone (ESE), dimethyl ether tetraethylene glycol (TEGDME), ethylene glycol dimethyl ether (DME), 1,3-dioxolane (DOL), trimethyl phosphate, 3-methoxypropionitrile, H(CF2)2OCH3, C4F9OCH3, H(CF2)2OCH2CH3, H(CF2)2OCH2CF3, H(CF2)2CH2O(CF2)2H, CF3CHFC F2OCH3, CF3CHFCF2OCH2CH3, 2-trifluoromethylhexafluoropropyl methyl ether, 2-trifluoromethylhexafluoropropyl ethyl ether, 2-trifluoromethylhexafluoropropyl propyl ether, 3-trifluoromethyloctafluorobutyl methyl ether, 3-trifluoromethyloctafluorobutyl ethyl ether, 3-trifluoromethyloctafluorobutyl propyl ether, 4-trifluoromethyldecafluoropentyl methyl ether, 4-trifluoromethyldecafluoropentyl ethyl ether, 4-trifluoromethyldecafluoropentyl propyl ether, 5-trifluoromethyldodecylfluorohexyl methyl ether, 5-trifluoromethyldodecylfluorohexyl ethyl ether, 5-trifluoromethyldodecylfluorohexyl propyl ether, 6-trifluoromethyltetradecylfluoroheptyl methyl ether, 6-trifluoromethyltetradecylfluoroheptyl ethyl ether, 6-trifluoromethyltetradecylfluoroheptyl propyl ether, 7-trifluoromethylhexadecylfluorooctyl methyl ether, 7-trifluoromethylhexadecylfluorooctyl ethyl ether, 7-trifluoromethylhexadecylfluorooctyl propyl ether.

[0092] In some embodiments, the electrolyte includes anion, which may include bis(fluorosulfonyl)imide anion (FSI). - ), bis(trifluoromethanesulfonyl)imide anion (TFSI)- ), dioxaborate anion (BOB) - ), difluorooxalate borate anion (DFOB) - ), difluorodioxanol phosphate anion (DFOP) - ), tetrafluorooxalate phosphate anion (TFOP) - ), difluorophosphate anion (PO2F2) - ), hexafluorophosphate anion (PF6) - ), tetrafluoroborate anion (BF4) - ), hexafluoroarsenate anion (AsF6) - ), trifluoromethanesulfonate anion (CF3SO3) - One or more of the following.

[0093] In some embodiments, the electrolyte includes cations, which may include one or more of lithium ions and sodium ions.

[0094] In some embodiments, the concentration of the electrolyte salt may be 0.3 mol / L or higher, optionally 0.7 mol / L or higher, and further optionally 4 mol / L or lower, optionally 2.5 mol / L or lower, or 1.7 mol / L or lower. When the concentration of the electrolyte salt is within the above range, the electrolyte can have a suitable ionic conductivity.

[0095] In some embodiments, the additive may also include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, and additives that improve battery low-temperature power performance.

[0096] [Positive electrode plate]

[0097] In some embodiments, the positive electrode active material may include one or more of lithium phosphate, layered lithium transition metal oxide, Prussian blue compounds, polyanionic compounds, and sodium transition metal oxide.

[0098] If the positive electrode active material is one or more of lithium phosphate and layered lithium transition metal oxide, then the positive electrode active material can be used in lithium-ion battery cells; if the positive electrode active material is one or more of Prussian blue compounds, polyanionic compounds, and sodium transition metal oxide, then the positive electrode material can be used in sodium-ion battery cells.

[0099] Lithium-containing phosphates may include one or more of lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, and their respective modified compounds.

[0100] Examples of layered lithium-containing transition metal oxides may include one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their respective modified compounds.

[0101] In some embodiments, the layered lithium-containing transition metal oxide may include Ni. The molar amount of Ni may account for more than 70% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide; optionally, the molar amount of Ni may account for more than 80% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide; more preferably, the molar amount of Ni may account for more than 90% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide.

[0102] The higher the Ni content in layered lithium-containing transition metal oxides, the higher the energy density of the battery cell.

[0103] In some embodiments, layered lithium-containing transition metal oxides may include Li a Ni b Co c M d O e A f Wherein, 0 < a ≤ 1.2; 0.8 ≤ b < 1; 0 < c < 1; 0 < d < 1; b + c + d = 1; 1 ≤ e ≤ 2; 0 ≤ f ≤ 1; M includes, but is not limited to, one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B; A includes, but is not limited to, one or more of N, F, S, and Cl. This can further improve the energy density of individual battery cells.

[0104] In some embodiments, as an example, layered lithium-containing transition metal oxides may include, but are not limited to, LiNi. 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.8 Co 0.15 Al 0.05 O2, LiNi 0.9 Co 0.06 Mn 0.04 O2, LiNi 0.92 Co 0.06 Mn 0.02 O2, LiNi 0.96 Co 0.02 Mn 0.02 O2, LiNi 0.96 Co 0.02 Mn 0.02 O2N 0.02 One or more of them.

[0105] During the charging and discharging process of a battery cell, Li undergoes insertion / extraction and consumption, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this application, the molar Li content refers to the initial state of the material, i.e., the state before feeding. After charge-discharge cycles, the molar Li content may change when the positive electrode active material is applied to the battery cell.

[0106] In some embodiments, as an example, sodium transition metal oxides may include, but are not limited to:

[0107] Na 1-x Cu h Fe k Mn l M 1 m O 2-y M 1 It is one or more of Li, Be, B, Mg, Al, K, Ca, Ti, Co, Ni, Zn, Ga, Sr, Y, Nb, Mo, In, Sn, and Ba, 0 <x≤0.33,0<h≤0.24,0≤k≤0.32,0<l≤0.68,0≤m<0.1,h+k+l+m=1,0≤y<0.2;

[0108] Na 0.67 Mn 0.7 Ni z M 2 0.3-z O2, where M 2 It is one or more of Li, Mg, Al, Ca, Ti, Fe, Cu, Zn and Ba, 0 <z≤0.1;

[0109] Na a Li b Ni c Mn d Fe e O2, of which 0.67 <a≤1,0<b<0.2,0<c<0.3,

[0110] 0.67 <d+e<0.8,b+c+d+e=1。

[0111] In some embodiments, as an example, the polyanionic compound may include, but is not limited to:

[0112] A 1 f M 3 g (PO4) i O j X 13-j , where A is one or more of H, Li, Na, K, and NH4, M 3 is one or more of Ti, Cr, Mn, Fe, Co, Ni, V, Cu, and Zn, X 1 is one or more of F, Cl, and Br, 0 < f ≤ 4, 0 < g ≤ 2, 1 ≤ i ≤ 3, 0 ≤ j ≤ 2;

[0113] Na n M 4 PO4X 2 , where M 4 is one or more of Mn, Fe, Co, Ni, Cu, and Zn, X 2 is one or more of F, Cl, and Br, 0 < n ≤ 2;

[0114] Na p M 5 q (SO4)3, where M 5 is one or more of Mn, Fe, Co, Ni, Cu, and Zn, 0 < p ≤ 2, 0 < q ≤ 2;

[0115] Na s Mn t Fe 3-t (PO4)2(P2O7), where 0 < s ≤ 4, 0 ≤ t ≤ 3, for example, t is 0, 1, 1.5, 2, or 3.

[0116] In some embodiments, by way of example, Prussian blue compounds may include, but are not limited to:

[0117] A u M 6 v [M 7 (CN)6] w ·xH2O, where A is H + , NH4 + , an alkali metal cation, and an alkaline earth metal cation, M 6 and M 7 are each independently one or more of transition metal cations, 0 < u ≤ 2, 0 < v ≤ 1, 0 < w ≤ 1, 0 < x < 6. For example, A is H + , Li + , Na + , K + , NH4 + , Rb + , Cs + , Fr + , Be 2+ , Mg 2+ , Ca2+ 、Sr 2+ Ba 2+ and Ra 2+ One or more of them, M 6 and M 7 Each is an independently selected cation of one or more transition metal elements chosen from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, and W. Optionally, A is Li. + Na + and K + One or more of them, M 6 It is a cation of one or more transition metal elements selected from Mn, Fe, Co, Ni, and Cu, M 7 It is a cation of one or more transition metal elements selected from Mn, Fe, Co, Ni and Cu.

[0118] In the examples of positive electrode active materials in this application, the molar content of O is only a theoretical value. Oxygen release from the crystal lattice will cause the molar content of O to change, and the actual molar content of O will fluctuate.

[0119] The modified compounds for the above-mentioned positive electrode active materials can be obtained by doping and / or surface coating of the positive electrode active materials.

[0120] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0121] In some implementations, the weight percentage of the binder in the positive electrode film layer is greater than or equal to 0.5%, which is beneficial for obtaining good adhesion performance.

[0122] In some embodiments, the positive electrode film layer further includes a conductive agent. As an example, 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.

[0123] In some embodiments, the positive 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 substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be made by forming a metal material, such as aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, on the polymer substrate. The polymer substrate may include polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), and other substrates.

[0124] In some embodiments, the thickness of the positive current collector is from 4 μm to 20 μm. It is optionally from 6 μm to 18 μm, and more preferably from 8 μm to 16 μm.

[0125] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0126] [Negative electrode plate]

[0127] In some embodiments, the negative electrode sheet includes a negative current collector and a negative electrode film layer located on at least one side of the negative current collector, the negative electrode film layer including a negative electrode active material.

[0128] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector. The negative electrode current collector can be made of materials such as metal foil, carbon-coated metal foil, or porous metal plate, and copper foil is an option.

[0129] As an example, the negative electrode active material may include one or more of the following: artificial graphite, natural graphite, mesophase micro carbon spheres, hard carbon, soft carbon, silicon, and silicon-carbon composites.

[0130] Silicon-based composite materials can be prepared by methods known in the art. For example, they can be prepared by vapor deposition using graphite and silicon materials as raw materials.

[0131] In some embodiments, the negative electrode film layer may further include a negative electrode conductive agent. As an example, the negative electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0132] In some embodiments, the negative electrode film layer may further include a negative electrode binder. As an example, the negative electrode binder may include, but is not limited to, one or more of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0133] In some embodiments, the negative electrode film layer may also include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC-Na), PTC thermistor materials, etc.

[0134] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. Examples of metal foils include copper foil, copper alloy foil, aluminum foil, and aluminum alloy foil. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one side of the polymeric material substrate. Examples of metal materials include, but are not limited to, one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Examples of polymeric material substrates include, but are not limited to, one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0135] The negative electrode sheet does not exclude other additional functional layers besides the negative electrode film layer. For example, in some embodiments, the negative electrode sheet may also include a conductive undercoat layer sandwiched between the negative electrode current collector and the negative electrode film layer and located on the surface of the negative electrode current collector, which may be composed of a conductive agent and a binder; in some embodiments, the negative electrode sheet may also include a protective layer covering the surface of the negative electrode film layer.

[0136] The negative electrode sheet can be prepared as follows: The negative electrode active material, negative electrode binder, negative electrode conductive agent, and optional other additives are dispersed in a solvent and stirred evenly to form a negative electrode slurry; the negative electrode slurry is coated onto a negative electrode current collector, and after drying, rolling, and other processes, a negative electrode sheet is formed. The solvent can be N-methylpyrrolidone (NMP) or deionized water, but is not limited to these.

[0137] [Isolation Component]

[0138] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0139] In some embodiments, the isolation chamber includes an isolation membrane. This application does not impose any particular limitation on the type of isolation membrane; any known porous membrane with good chemical and mechanical stability can be selected.

[0140] In some embodiments, the material of the separator may include at least one selected from glass fiber, nonwoven 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. The separator may be a single component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating may also be applied to the surface of the separator.

[0141] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0142] Example

[0143] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0144] Example 1

[0145] Positive electrode sheet

[0146] The positive electrode active material lithium iron phosphate (LiFePO4), conductive agent conductive carbon black, and binder polyvinylidene fluoride (PVDF) are mixed in a mass ratio of 8:1:1 and then added to the solvent N-methylpyrrolidone (NMP) to uniformly disperse and obtain a positive electrode slurry. The positive electrode slurry is coated onto the surface of the positive electrode current collector aluminum foil, and then dried, cold-pressed, and slit to obtain the positive electrode sheet.

[0147] Negative electrode sheet

[0148] A negative electrode slurry is prepared by uniformly mixing graphite (a negative electrode active material), conductive carbon black (a conductive agent), sodium carboxymethyl cellulose (CMC-Na) (a thickener), and styrene-butadiene rubber (SBR) (a binder) in deionized water at a mass ratio of 95:1:1:3. The negative electrode slurry is then uniformly coated onto copper foil (a negative electrode current collector), and the negative electrode sheet is obtained by cold pressing and slitting.

[0149] Separating membrane

[0150] A polyethylene (PE) film with a thickness of 12μm was selected.

[0151] electrolyte

[0152] Ethylene carbonate, diethyl carbonate, dimethyl carbonate, and isoxazole compounds with structures shown in Table 1 were mixed in a volume ratio of 1:1:1:3. Lithium hexafluorophosphate (LiPF6), lithium nitrate, and copper fluoride were dissolved in the above solution to obtain an electrolyte. In the electrolyte, the mass content of lithium nitrate was 1%, the mass content of copper fluoride was 0.2%, and the concentration of LiPF6 was 1 mol / L.

[0153] battery cell

[0154] The positive electrode, negative electrode, and separator are stacked in sequence and then injected with electrolyte to obtain a coin cell.

[0155] Examples 2 to 12

[0156] The preparation method of the battery cell is similar to that in Example 1, except that the composition of the electrolyte is different. For details of the parameter adjustments, please refer to Table 1.

[0157] Table 1

[0158]

[0159]

[0160] Comparative Example 1

[0161] The preparation method of the battery cell is similar to that in Example 1, except that the composition and preparation parameters of the electrolyte are different, as detailed below:

[0162] Ethylene carbonate, diethyl carbonate, and dimethyl carbonate were mixed in a volume ratio of 1:1:1. Lithium hexafluorophosphate (LiPF6) was dissolved in the mixture to obtain the electrolyte. The concentration of LiPF6 in the electrolyte was 1 mol / L.

[0163] Comparative Example 2

[0164] The preparation method of the battery cell is similar to that in Example 1, except that the composition and preparation parameters of the electrolyte are different, as detailed below:

[0165] Ethylene carbonate, diethyl carbonate, and dimethyl carbonate were mixed in a volume ratio of 1:1:1. Lithium hexafluorophosphate (LiPF6), lithium nitrate, and copper fluoride were dissolved in the mixture to obtain the electrolyte. The electrolyte contained 1% lithium nitrate, 0.2% copper fluoride, and 1 mol / L LiPF6.

[0166] Comparative Example 3

[0167] The preparation method of the battery cell is similar to that in Example 1, except that the composition parameters of the electrolyte are different. Specifically, no nitrates and fluorides are added to the electrolyte.

[0168] Comparative Example 4

[0169] The preparation method of the battery cell is similar to that in Example 1, except that the composition parameters of the electrolyte are different, specifically: no nitrate is added to the electrolyte.

[0170] Comparative Example 5

[0171] The preparation method of the battery cell is similar to that in Example 1, except that the composition parameters of the electrolyte are different, specifically: no fluoride is added to the electrolyte.

[0172] Test section

[0173] 1. Electrolyte viscosity

[0174] Under ambient humidity <80%, take 30 mL of sample and keep it at a constant temperature of 25℃ in a water bath for at least 30 minutes. Place the rotor into the sample cup, add sample to approximately 0.3 cm from the rim, start the viscometer, and rotate at 70 RPM for 5 minutes to obtain the viscosity value. Ten data points can be collected during the test, and the average value is taken. The testing instrument is a Bollerfeld DV-2TLV viscometer.

[0175] 2. Electrolyte ionic conductivity

[0176] Take an appropriate amount of electrolyte and divide it into three equal portions. Then, use a conductivity meter to measure the conductivity of each sample at 25℃. Take the average value of the test results as the conductivity of the electrolyte. The testing instrument is a DDS-307 conductivity meter.

[0177] 3. Specific capacity of individual battery cells

[0178] At 25°C, the battery cell is charged at a constant current of 0.33C to the upper limit of the cutoff voltage, then charged at a constant voltage to 0.05C, and then discharged at a constant current of 0.33C to the lower limit of the cutoff voltage. The ratio of the initial discharge capacity of the battery cell to the mass of the active material is used as the specific capacity of the battery cell.

[0179] 4. Room temperature charging performance

[0180] At 25℃, with the negative electrode potential of 0mV as the cutoff condition, the maximum SOC that can be achieved under different charging rates is tested, and then the equivalent charging rate is calculated to detect the charging capability of the battery cell at room temperature.

[0181] 5. Low-temperature charging performance

[0182] At a temperature of -10℃, with the negative electrode potential of 0mV as the cutoff condition, the maximum charge capacity (SOC) that can be achieved under different charging rates is tested, and then the equivalent charging rate is calculated to detect the charging capability of the battery cell at low temperatures.

[0183] The test results are detailed in Table 2.

[0184] Table 2

[0185]

[0186]

[0187] Based on the data in Table 2, the electrolyte provided in this application embodiment has a lower viscosity at low temperatures, which can improve the conductivity of the electrolyte and thus improve the fast charging capability of the battery cell.

[0188] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A battery cell, characterized in that, It includes an electrolyte, which comprises an organic solvent and additives, wherein the organic solvent comprises isoxazole compounds and the additives comprise nitrates and fluorides.

2. The battery cell according to claim 1, characterized in that, The isoxazole compounds include those shown in Formula 1: R1, R2, and R3 are each independently selected from hydrogen atoms and unsubstituted or heteroatom-substituted alkyl groups with 1-10 carbon atoms.

3. The battery cell according to claim 2, characterized in that, The heteroatom includes one or more of halogen atoms, N, P, S, O, and B.

4. The battery cell according to claim 2 or 3, characterized in that, The isoxazole compounds include one or more of the following compounds:

5. The battery cell according to any one of claims 1 to 4, characterized in that, Based on the total volume of the organic solvent, the volume content of the isoxazole compound is 10% to 90%.

6. The battery cell according to any one of claims 1 to 5, characterized in that, The nitrates include one or more of lithium nitrate, sodium nitrate, potassium nitrate, copper nitrate, zinc nitrate, magnesium nitrate, and aluminum nitrate.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The nitrate content in the electrolyte is 0.1% to 5% by mass.

8. The battery cell according to any one of claims 1 to 7, characterized in that, The fluoride includes one or more of lithium fluoride, sodium fluoride, potassium fluoride, copper fluoride, zinc fluoride, magnesium fluoride, and aluminum fluoride.

9. The battery cell according to any one of claims 1 to 8, characterized in that, The fluoride content in the electrolyte is 0.1% to 5% by mass.

10. The battery cell according to any one of claims 1 to 9, characterized in that, The mass ratio of the nitrate to the fluoride is 1:(0.02-50); and / or The mass ratio of the isoxazole compound to the nitrate is (10-90):

1.

11. The battery cell according to any one of claims 1 to 10, characterized in that, The organic solvent also includes carbonates, the volume content of which is 10% to 90% based on the total volume of the organic solvent.

12. A battery device, characterized in that, Includes the battery cell according to any one of claims 1 to 11.

13. An electrical appliance, characterized in that, Includes the battery device as described in claim 12.

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