Electrolytes, batteries and power consuming devices

Abstract

The present application provides an electrolyte, a battery, and a power consumption device. The electrolyte of the present application comprises a first additive represented by formula (I), where R is one or more selected from halogens and MO-, and M is selected from alkali metals. The electrolyte of the present application can suppress HF corrosion of the negative electrode and positive electrode SEI films, reduce oxidation-reduction reactions between the electrolyte and the positive electrode or negative electrode, reduce the consumption of active lithium, suppress solvent decomposition in the electrolyte, reduce the amount of gas generated by solvent decomposition, improve the cycle and storage performance of secondary batteries, and reduce the volume expansion and impedance of the battery core. JPEG2025532278000016.jpg41170

Description

[Technical Field]

[0001] This application relates to the field of battery technology, and more particularly to electrolytes, batteries and power consuming devices. [Background technology]

[0002] In recent years, as the application range of secondary batteries becomes wider and wider, secondary batteries are widely used in energy storage power supply systems such as hydroelectric power, thermal power, wind power and solar power plants, as well as in multiple fields such as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc. As secondary batteries have made great progress, higher requirements are being placed on their energy density, cycle performance and safety performance.

[0003] Fluorine-containing electrolyte salts in the electrolytes used in batteries are hydrolyzed at high temperatures to generate HF, which easily erodes the SEI film of the electrode plate, causing problems such as increased consumption of active lithium, increased impedance and volume expansion of the battery core, and reduced cycle performance and storage performance of the battery. Therefore, there is an urgent need to solve these problems. Summary of the Invention [Problem to be solved by the invention]

[0004] The present application has been made in view of the above-mentioned problems, and its purpose is to provide an electrolyte, a battery, and a power consumption device. By adopting the electrolyte of the present application, it is possible to reduce the erosion of the SEI film of the electrode plate caused by HF generated by the hydrolysis of the fluorine-containing electrolyte salt, reduce the consumption of active lithium, improve the cycle performance and storage performance of the secondary battery, and reduce the impedance and volume expansion of the battery core. [Means for solving the problem]

[0005] To achieve the above object, a first aspect of the present application provides an electrolyte, the electrolyte comprising a first additive represented by formula (I): [ka] where: R is one or more selected from halogen and MO-, and M is selected from alkali metals.

[0006] The first additive in the electrolyte of the present application inhibits corrosion of the negative electrode SEI film and the positive electrode SEI film by HF generated by hydrolysis of the fluorine-containing electrolyte salt, and reduces the oxidation-reduction reaction between the electrolyte and the positive electrode or the negative electrode, thereby reducing the consumption of active lithium and improving the cycle performance of the secondary battery. The first additive also reduces solvent decomposition in the electrolyte induced by HF and reduces the amount of gas generated by solvent decomposition, thereby reducing the volume expansion and impedance of the battery core and improving the storage performance of the secondary battery.

[0007] In any embodiment, R is one or more selected from F and MO-, and / or M is one or more selected from lithium, sodium, potassium, rubidium, and cesium; Optionally, M is one or more selected from lithium, sodium, and potassium; More preferably, M is lithium.

[0008] In any embodiment, the first additive is one or more selected from lithium sulfamate, aminosulfonyl fluoride, sodium sulfamate, and potassium sulfamate; Optionally, the first additive is one or more selected from lithium sulfamate and aminosulfonyl fluoride.

[0009] As a result, the first additive can further inhibit the erosion of the positive electrode SEI film or the negative electrode SEI film by HF, reduce the consumption of active lithium, further improve the cycle performance of the secondary battery, further reduce the volume expansion and impedance of the battery core, and further improve the storage performance of the secondary battery.

[0010] In any embodiment, the mass content of the first additive in the electrolyte is 3.5% or less, optionally 10 ppm to 3.5%, more preferably 10 ppm to 3%, even more preferably 500 ppm to 1%, and even more preferably 0.1% to 1%.

[0011] The first additive in the above content range can further improve the cycle performance and storage performance of the secondary battery, and further reduce the impedance of the battery core.

[0012] In any embodiment, the electrolyte further comprises a second additive according to Formula (II) or Formula (III): [ka] [ka] where: In formula (II) and formula (III), E is each independently one or more selected from phosphorus and boron; In formula (II) and formula (III), G is independently selected from halogen; and, when E is phosphorus, x is 2 and y is 2; When E in formula (II) is boron, x is 4 and y is 0, or x is 2 and y is 1; When E in formula (III) is boron, x is 4 and y is 0.

[0013] By using the second additive and the first additive simultaneously, the impedance of the battery core can be further reduced, the expansion rate of the battery core can be further reduced, and the cycle performance and storage performance of the secondary battery can be further improved.

[0014] In either embodiment, each G in formula (II) and formula (III) is independently F.

[0015] In any embodiment, the second additive is one or more selected from lithium difluorophosphate, lithium difluorobis(oxalato)phosphate, lithium tetrafluoroborate, and lithium difluoro(oxalato)borate; Optionally, the second additive is one or more selected from lithium difluorophosphate, lithium tetrafluoroborate, and lithium difluoro(oxalato)borate.

[0016] By using the second additive and the first additive in combination, the impedance and volume expansion of the battery core can be further reduced, and the cycle performance and storage performance of the secondary battery can be improved.

[0017] In any embodiment, the mass content of the second additive in the electrolyte is 2.3% or less, optionally 100 ppm to 2.3%, more optionally 100 ppm to 2%, and even more optionally 0.1% to 1%.

[0018] The content of the second additive within the above range is advantageous for further improving the cycle performance and storage performance of the secondary battery.

[0019] In any embodiment, the ratio of the mass content of the second additive in the electrolyte to the mass content of the first additive in the electrolyte is 0.1 to 500, optionally 0.5 to 12, and more optionally 0.5 to 10. This allows for the production of a battery with excellent overall performance.

[0020] In any embodiment, the electrolyte salt further comprises one or more selected from LiPF, lithium bis(fluorosulfonyl)imide, lithium fluorosulfonate, lithium fluorosulfonyl(trifluoromethylsulfonyl)imide, and lithium bis(pentafluoroethylsulfonyl)imide, and optionally one or more selected from LiPF and lithium bis(fluorosulfonyl)imide.

[0021] The first additive and the optional second additive have a more obvious improving effect on the electrolyte system containing the above electrolyte salt, and can further improve the cycle performance and storage performance of the secondary battery, and further reduce the volume expansion and impedance of the battery core.

[0022] A second aspect of the present application further provides a battery, the battery comprising the electrolyte of the first aspect of the present application.

[0023] As a result, the first additive in the electrolyte of the present application can suppress the erosion of the negative electrode SEI film and the positive electrode SEI film by HF generated by the hydrolysis of the fluorine-containing electrolyte salt, and reduce the oxidation-reduction reaction between the electrolyte and the positive electrode or the negative electrode, thereby reducing the consumption of active lithium and improving the cycle performance of the secondary battery. The first additive can also reduce the solvent decomposition in the electrolyte induced by HF and reduce the amount of gas generated by the solvent decomposition, thereby reducing the volume expansion and impedance of the battery core and improving the storage performance of the secondary battery.

[0024] A third aspect of the present application provides a power consuming device, the power consuming device including a battery of the second aspect of the present application. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic diagram of a secondary battery according to an embodiment of the present application; [Figure 2] FIG. 2 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. [Figure 3] 1 is a schematic diagram of a battery module according to an embodiment of the present application; [Figure 4] 1 is a schematic diagram of a battery pack according to an embodiment of the present application; [Figure 5] FIG. 5 is an exploded view of the battery pack according to the embodiment of the present application shown in FIG. 4. [Figure 6] 1 is a schematic diagram of a power consumption device in which a secondary battery according to an embodiment of the present application is used as a power source; DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, with reference to the drawings as appropriate, embodiments specifically disclosing the electrolyte, battery, and power consumption device of the present application will be described in detail. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters and redundant description of actually identical structures may be omitted. This is to avoid the following description becoming unnecessarily long and to facilitate understanding by those skilled in the art. Note that the drawings and the following description are provided to enable those skilled in the art to fully understand the present application, and are not intended to limit the subject matter described in the claims.

[0027] The "ranges" disclosed in this application are defined in the form of lower and upper limits, and a given range is defined by selecting one lower limit and one upper limit, with the selected lower and upper limits defining the boundaries of the particular range. Such defined ranges may be inclusive or exclusive of their endpoints, and are arbitrarily combinable; i.e., any lower limit can be combined with any upper limit to form a single range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if 1 and 2 are listed as minimum range values ​​and 3, 4, and 5 are listed as maximum range values, the ranges of 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5 are all contemplated. In this application, unless otherwise specified, a numerical range "a to b" is a shorthand representation of any combination of real numbers a to b, where a and b are both real numbers. For example, the numerical range "0 to 5" represents a list of all real numbers between "0 and 5" in this specification, and "0 to 5" is merely a shorthand representation of combinations of these numbers. Also, expressing a parameter as an integer ≧2 is equivalent to disclosing that this parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0028] Unless otherwise stated, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0029] Unless otherwise stated, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0030] Unless otherwise stated, all steps in this application may be performed in order or randomly, preferably in order. For example, a method including steps (a) and (b) means that the method may include steps (a) and (b) performed in order, or may include steps (b) and (a) performed in order. For example, a method that may further include step (c) means that step (c) may be added to the method in any order, e.g., the method may include steps (a), (b), and (c), or may include steps (a), (c), and (b), or may include steps (c), (a), and (b), etc.

[0031] Unless otherwise specified, the terms "comprise" and "comprises" used in this application may be open-ended or closed-ended. For example, "comprise" and "comprises" may indicate that other components not listed may be further included or included, or that only the listed components may be included or included.

[0032] Unless otherwise stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the following conditions satisfy "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) but B is true (or exists); and both A and B are true (or exist).

[0033] Unless otherwise stated, in this application, the term "halogen" refers generically to the Group VIIA elements of the periodic table, including fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and the like.

[0034] Unless otherwise specified, in this application, the term "alkali metal" refers to a metallic element in Group IA of the periodic table other than hydrogen, including lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and the like.

[0035] [Secondary battery] A secondary battery is also called a rechargeable battery or a storage battery, and is a battery that can be continuously used by activating the active material through charging after discharging the battery.

[0036] Generally, a secondary battery includes a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. During charging and discharging of the battery, active ions (e.g., lithium ions) are absorbed and released by shuttle movement between the positive electrode plate and the negative electrode plate. The separator, located between the positive electrode plate and the negative electrode plate, primarily serves to prevent short-circuiting between the positive and negative electrodes and allows the active ions to pass through. The electrolyte primarily serves to conduct the active ions between the positive electrode plate and the negative electrode plate.

[0037] [Electrolytes] One embodiment of the present application provides an electrolyte, comprising a first additive represented by formula (I): [ka] where: R is one or more selected from halogen and MO-, and M is selected from alkali metals.

[0038] HF generated by, for example, the hydrolysis of the fluorine-containing electrolyte salt in the electrolyte corrodes the positive electrode SEI film and the negative electrode SEI film. After the SEI film is corroded, the exposed positive electrode material or negative electrode material is prone to oxidation-reduction reactions with the electrolyte, which leads to excessive consumption of active lithium and reduces the cycle performance and storage performance of the secondary battery. HF also induces solvent decomposition in the electrolyte to generate gas, which leads to volume expansion of the battery core and an increase in impedance, thereby reducing the high-temperature storage performance of the secondary battery.

[0039] The amino group in the first additive in the electrolyte of the present application can bond with HF generated by hydrolysis, and the sulfonic acid group can also participate in film formation, inhibiting the erosion of the positive electrode SEI film or the negative electrode SEI film by HF and inhibiting the redox reaction between the electrolyte and the positive electrode material or the negative electrode material, thereby reducing the consumption of active lithium and improving the cycle performance and storage performance of the secondary battery. Furthermore, the bond between the amino group in the first additive and HF can inhibit gas generation due to solvent decomposition, reduce the volume expansion and impedance of the battery core, and further improve the high-temperature storage performance of the secondary battery.

[0040] In some embodiments, R is one or more selected from F and MO-, and / or M is one or more selected from lithium, sodium, potassium, rubidium, and cesium; Optionally, M is one or more selected from lithium, sodium, and potassium; More preferably, M is lithium.

[0041] In some embodiments, the first additive is one or more selected from lithium sulfamate, aminosulfonyl fluoride, sodium sulfamate, and potassium sulfamate; Optionally, the first additive is one or more selected from lithium sulfamate and aminosulfonyl fluoride.

[0042] The first additive can further inhibit the erosion of the positive electrode SEI film or the negative electrode SEI film by HF, reduce the consumption of active lithium, further improve the cycle performance of the secondary battery, further reduce the volume expansion and impedance of the battery core, and further improve the storage performance of the secondary battery.

[0043] In this application, lithium sulfamate, aminosulfonyl fluoride, sodium sulfamate and potassium sulfamate are, in this order: [ka] The structure is as follows.

[0044] In some embodiments, the mass content of the first additive in the electrolyte is 3.5% or less, optionally 10 ppm to 3.5%, more preferably 10 ppm to 3%, even more preferably 500 ppm to 1%, and even more preferably 0.1% to 1%, such as 10 ppm, 500 ppm, 0.1%, 0.5%, 1%, 3%, 3.5%, and any number in the range above.

[0045] Therefore, the first additive in the above content range can further improve the cycle performance and storage performance of the secondary battery and further reduce the impedance of the battery core.

[0046] In some embodiments, the electrolyte further comprises a second additive according to Formula (II) or Formula (III): [ka] [ka] where: In formula (II) and formula (III), E is each independently one or more selected from phosphorus and boron; In formula (II) and formula (III), G is independently selected from halogen; and, when E is phosphorus, x is 2 and y is 2; When E in formula (II) is boron, x is 4 and y is 0, or x is 2 and y is 1; When E in formula (III) is boron, x is 4 and y is 0.

[0047] When the first additive participates in film formation, by-products tend to accumulate on the surface of the positive electrode, which increases the impedance at the positive electrode interface and the impedance of the battery core.Compared to the first additive, the second additive can preferentially form a film at the positive electrode interface, thereby reducing the impact of the by-products of the first additive on the impedance at the positive electrode interface, further reducing the impedance of the battery core, further reducing the expansion rate of the battery core, and improving the cycle performance and storage performance of the secondary battery.

[0048] In either embodiment, each G in formula (II) and formula (III) is independently F.

[0049] In some embodiments, the second additive is one or more selected from lithium difluorophosphate, lithium difluorobis(oxalato)phosphate, lithium tetrafluoroborate, and lithium difluoro(oxalato)borate; Optionally, the second additive is one or more selected from lithium difluorophosphate, lithium tetrafluoroborate, and lithium difluoro(oxalato)borate.

[0050] By using the second additive and the first additive simultaneously, the impedance of the battery core can be further reduced, the expansion rate of the battery core can be further reduced, and the cycle performance and storage performance of the secondary battery can be further improved.

[0051] In this application, lithium difluorophosphate, lithium difluorobis(oxalato)phosphate, lithium tetrafluoroborate, and lithium difluoro(oxalato)borate are referred to as: [ka] The structure is as follows.

[0052] In some embodiments, the mass content of the second additive in the electrolyte is 2.3% or less, optionally 100 ppm to 2.3%, more optionally 100 ppm to 2%, and even more optionally 0.1% to 1%, such as 100 ppm, 0.1%, 0.3%, 0.5%, 1%, 1.2%, 2%, 2.3%, and any number in the range above.

[0053] The content of the second additive within the above range is advantageous for further improving the cycle performance and storage performance of the secondary battery.

[0054] In some embodiments, the ratio of the mass content of the second additive in the electrolyte to the mass content of the first additive in the electrolyte is 0.1 to 500, optionally 0.5 to 12, more optionally 0.5 to 10, such as 0.1, 0.2, 0.5, 1, 3, 4, 4.6, 5, 10, 12, 500, and any number in the range above, thereby providing a battery with excellent overall performance.

[0055] The electrolyte serves to conduct ions between the positive and negative plates and may be, for example, a liquid, a gel, or an all-solid state.

[0056] In some embodiments, the electrolyte is liquid and includes an electrolyte salt and a solvent.

[0057] In some embodiments, the electrolyte salt is one or more selected from LiPF, lithium bis(fluorosulfonyl)imide, lithium fluorosulfonate, lithium fluorosulfonyl(trifluoromethylsulfonyl)imide, and lithium bis(pentafluoroethylsulfonyl)imide, preferably one or two selected from LiPF and lithium bis(fluorosulfonyl)imide, more preferably LiPF.

[0058] The first additive and the optional second additive have a more obvious improving effect on the electrolyte system containing the above electrolyte salt, and can further improve the cycle performance and storage performance of the secondary battery, and further reduce the volume expansion and impedance of the battery core.

[0059] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluorinated ethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, ethyl methyl sulfone, and diethyl sulfone.

[0060] In some embodiments, the electrolyte solution may further optionally contain other additives, such as additives that can improve the overcharge performance of the secondary battery, or additives that can improve the high-temperature or low-temperature performance of the secondary battery.

[0061] In some embodiments, the mass content of water in the electrolyte does not exceed 50 ppm, optionally does not exceed 20 ppm.

[0062] In some embodiments, the conductivity of the electrolyte is selected from the range of 7 mS / cm to 15 mS / cm.

[0063] In some embodiments, the low temperature freezing point of one of the electrolytes at standard atmospheric pressure is selected from the range of -80°C to -20°C.

[0064] [Positive electrode plate] The positive electrode plate generally includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, and the positive electrode film layer includes a positive electrode active material.

[0065] For example, the positive electrode current collector has two surfaces that face each other in the thickness direction thereof, and the positive electrode film layer is disposed on either one or both of the two facing surfaces of the positive electrode current collector.

[0066] In some embodiments, the positive electrode current collector may be a metal foil sheet or a composite current collector. For example, aluminum foil may be used as the metal foil sheet. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base layer. The composite current collector may be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0067] In some embodiments, the positive electrode active material may be a positive electrode active material known in the art and used in batteries. For example, the positive electrode active material may include at least one of a lithium-containing phosphate with an olivine structure, a lithium transition metal oxide, and a modified compound of each. However, the present application is not limited to these materials, and other conventional materials usable as positive electrode active materials in batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Here, examples of lithium transition metal oxides include lithium cobalt oxide (e.g., LiCoO), lithium nickel oxide (e.g., LiNiO), lithium manganese oxide (e.g., LiMnO, LiMnO), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM 333 (may be abbreviated as "LiNi") 0.5 Co 0.2 Mn0.3 O2(NCM 523 (may be abbreviated as "LiNi") 0.5 Co 0.25 Mn 0.25 O2(NCM 211 (may be abbreviated as "LiNi") 0.6 Co 0.2 Mn 0.2 O2(NCM 622 (may be abbreviated as "LiNi") 0.8 Co 0.1 Mn 0.1 O2(NCM 811 ), lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05 Examples of the lithium-containing phosphate having an olivine structure may include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (which may be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.

[0068] In some embodiments, the positive electrode membrane layer optionally further comprises an adhesive. For example, the adhesive may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0069] In some embodiments, the positive electrode film layer optionally further comprises a conductive agent, for example, the conductive agent may comprise at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0070] In some embodiments, a positive electrode plate can be manufactured in the following manner: Components for manufacturing the positive electrode plate, such as a positive electrode active material, a conductive agent, an adhesive, and any other components, are dispersed in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry, which is then coated onto a positive electrode current collector, and the positive electrode plate is obtained after processes such as drying and cold pressing.

[0071] [Negative electrode plate] The negative electrode plate includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.

[0072] For example, the negative electrode current collector has two surfaces that face each other in the thickness direction thereof, and the negative electrode film layer is disposed on either one or both of the two facing surfaces of the negative electrode current collector.

[0073] In some embodiments, the negative electrode current collector may be a metal foil sheet or a composite current collector. For example, the metal foil sheet may be copper foil. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base. The composite current collector may be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymer base (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0074] In some embodiments, the negative electrode active material may be any negative electrode active material known in the art. For example, the negative electrode active material may include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of silicon, silicon oxide, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of tin, tin oxide, and tin alloys. However, the present application is not limited to these materials, and other conventional materials usable as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination.

[0075] In some embodiments, the negative electrode membrane layer optionally further comprises an adhesive, which may be selected from at least one of styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0076] In some embodiments, the negative electrode film layer optionally further comprises a conductive agent, for example, the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0077] In some embodiments, the negative electrode membrane layer optionally further comprises other additives, such as a thickener (eg, sodium carboxymethylcellulose (CMC-Na)).

[0078] In some embodiments, the negative electrode plate can be manufactured in the following manner: Components for manufacturing the negative electrode plate, such as a negative electrode active material, a conductive agent, an adhesive, and any other components, are dispersed in a solvent (e.g., deionized water) to form a negative electrode slurry, which is then coated onto a negative electrode current collector, and the negative electrode plate is obtained after processes such as drying and cold pressing.

[0079] [Separator] In some embodiments, the secondary battery further includes a separator. The present application does not particularly limit the type of separator, and any known porous separator with good chemical and mechanical stability may be selected.

[0080] In some embodiments, the separator may be made of at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, without any particular limitation. When the separator is a multi-layer composite film, the materials of each layer may be the same or different, without any particular limitation.

[0081] In some embodiments, the positive and negative electrodes and the separator can be fabricated into an electrode assembly by a winding or lamination process.

[0082] In some embodiments, the secondary battery may include an exterior body, which may be used to package the electrode assembly and electrolyte.

[0083] In some embodiments, the exterior of the secondary battery may be a hard case, such as a hard plastic case, an aluminum case, a steel case, etc. The exterior of the secondary battery may be a pouch, such as a bag-shaped pouch. The pouch may be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0084] The present application does not particularly limit the shape of the secondary battery, which may be cylindrical, rectangular, or any other shape. For example, Figure 1 shows an example of a rectangular secondary battery 5.

[0085] In some embodiments, referring to FIG. 2 , the exterior body may include a case 51 and a cover plate 53. Here, the case 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and side plate surround the periphery to form a receiving cavity. The case 51 has an opening communicating with the receiving cavity, and the cover plate 53 can cover the opening to seal the receiving cavity. The positive electrode plate, the negative electrode plate, and the separator may be formed into an electrode assembly 52 by a winding process or a stacking process. The electrode assembly 52 is packaged in the receiving cavity. An electrolyte is impregnated into the electrode assembly 52. ​​The number of electrode assemblies 52 included in the secondary battery 5 may be one or more, and those skilled in the art can select the number according to actual needs.

[0086] In some embodiments, the secondary batteries may be assembled into a battery module, and the number of secondary batteries included in the battery module may be one or more, and the specific number can be selected by those skilled in the art depending on the application and capacity of the battery module.

[0087] Fig. 3 shows an example of a battery module 4. Referring to Fig. 3, in the battery module 4, a plurality of secondary batteries 5 may be arranged in order along the longitudinal direction of the battery module 4. Of course, they may be arranged in any other manner. Furthermore, the plurality of secondary batteries 5 may be fixed by fasteners.

[0088] Optionally, the battery module 4 may further include a housing having an accommodating space, and the plurality of secondary batteries 5 are accommodated in this accommodating space.

[0089] In some embodiments, the battery modules may be further assembled into a battery pack, and the number of battery modules included in the battery pack may be one or more, the specific number of which can be selected by those skilled in the art depending on the application and capacity of the battery pack.

[0090] 4 and 5 show an example of a battery pack 1. Referring to FIGS. 4 and 5, the battery pack 1 may include a battery box and a plurality of battery modules 4 installed in the battery box. The battery box includes an upper housing 2 and a lower housing 3, and the upper housing 2 covers the lower housing 3 to form a sealed space for accommodating the battery modules 4. The plurality of battery modules 4 may be arranged in the battery box in any manner.

[0091] The present application also provides a power consuming device, the power consuming device including at least one of a secondary battery, a battery module, or a battery pack according to the present application. The secondary battery, the battery module, or the battery pack may be used as a power source for the power consuming device or as an energy storage unit for the power consuming device. The power consuming device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, energy storage systems, etc.

[0092] The power consumption device can be selected from a secondary battery, a battery module, or a battery pack depending on its usage needs.

[0093] 6 shows an example of a power consuming device, such as a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the demand for high power output and high energy density of the secondary battery of the power consuming device, a battery pack or battery module can be employed.

[0094] [Example] Examples of the present application are described below. The examples described below are illustrative and are used only to interpret the present application, and should not be understood as limitations on the present application. If specific techniques or conditions are not specified in the examples, they will be performed according to the techniques or conditions described in literature in the field or according to the product instructions. If the manufacturer of the reagents or instruments used is not specified, they are all commercially available ordinary products.

[0095] Example 1 (1) Preparation of electrolyte: In a glove box filled with argon gas (water content <10 ppm, oxygen gas content <1 ppm), add appropriate amounts of the first additive lithium sulfamate and the second additive lithium difluorophosphate to a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (EC:EMC = 3:7 W% / W%) and mix uniformly. Then, add LiPF6 slowly until the lithium salt is completely dissolved to obtain an electrolyte, in which the mass content of lithium sulfamate is 10 ppm, the mass content of lithium difluorophosphate is 0.5%, the molar concentration of LiPF6 is 1 M, and the mass content of water in the electrolyte is ≦20 ppm.

[0096] (2) Manufacturing of positive electrode plate: Positive electrode active material LiNi 0.5 Co 0.2 Mn 0.3 The positive electrode slurry was prepared by adding O2, the conductive agent Super P, and the adhesive polyvinylidene fluoride (PVDF) to N-methylpyrrolidone (NMP). The solid content of the positive electrode slurry was 50 wt%, and the solid component was LiNi 0.5 Co 0.2 Mn 0.3 The mass ratio of O2, Super P, and PVDF was 8:1:1. The positive electrode slurry was applied to an aluminum foil current collector, dried at 85°C, cold pressed, edge trimmed, film cut, slit, and then dried in a vacuum at 85°C for 4 hours to obtain a positive electrode plate.

[0097] (3) Preparation of negative electrode plate: The negative electrode active material, graphite, conductive agent Super P, thickener CMC, and adhesive styrene-butadiene rubber (SBR), were uniformly mixed in deionized water to prepare a negative electrode slurry. The solid content of the negative electrode slurry was 30 wt%, and the mass ratio of graphite, Super P, CMC, and adhesive styrene-butadiene rubber (SBR) in the solid components was 80:15:3:2. The negative electrode slurry was applied to a copper foil current collector, dried at 85°C, cold pressed, edge trimmed, film cut, and slit, and then dried in a vacuum at 120°C for 12 hours to obtain a negative electrode plate.

[0098] (4) Separator: A 16 μm polyethylene film (PE) was used.

[0099] (5) Manufacture of secondary battery: The manufactured positive electrode plate, separator, and negative electrode plate were stacked in this order, and a separator was placed between the positive and negative electrode plates to isolate the positive and negative electrodes. The stack was then wound to obtain a bare cell. The tabs were welded, and the bare cell was placed in an outer casing. The manufactured electrolyte was then injected into the dried battery core, followed by packaging, standing, chemical formation, shaping, capacity testing, etc., to complete the manufacture of the secondary battery (pouch lithium-ion battery: thickness 4.0 mm, width 60 mm, length 140 mm).

[0100] Examples 2 to 19 and Comparative Examples 1 and 2 are similar to the secondary battery manufacturing method of Example 1, and the details of the different parameters are as shown in Table 1, while the rest are the same as Example 1.

[0101] [Table 1] Parameters of Examples 1 to 19 and Comparative Examples 1 and 2 [Table 1A] [Table 1B]

[0102] Battery Test (1) Secondary battery cycle performance test The environmental temperature was adjusted to 25°C, and the secondary battery was charged at a constant current of 1C to 4.25V, and then further charged at a constant voltage of 4.25V until the current reached 0.05C. The battery was left to stand for 10 minutes, and then discharged at 1C to 2.8V. The discharge capacity C0 at this time was recorded, and the battery was cycled 300 times according to the charge / discharge flow described above. The discharge capacity at the 300th cycle was designated as C1, and the cycle capacity retention rate of the secondary battery was calculated according to the following formula. Secondary battery cycle capacity retention rate = 100% × C0 / C1 (2) High-temperature storage gas generation test for secondary batteries At 25°C, the secondary battery was charged at a constant current of 1C to 4.25V, and then further charged at a constant voltage of 4.25V until the current reached 0.05C. The volume of the battery core was then tested using the drainage method and recorded as V1. The moisture on the surface of the battery core was wiped off, and the secondary battery was placed in a thermostatic box at 70°C and kept warm for 10 days (the battery was not operated during this period). After being removed, the temperature was lowered to 25°C, and the volume of the battery core was again tested using the drainage method and recorded as V2. The volume expansion rate of the battery core was calculated according to the following formula: Battery core volume expansion rate = 100% × (V2-V1) / V1 (3) High-temperature storage life test for secondary batteries At 25°C, the secondary battery was charged at a constant current of 1C to 4.25V, further charged at a constant voltage of 4.25V until the current reached 0.05C, allowed to stand for 10 minutes, and then discharged at 1C to 2.8V. The discharge capacity D0 at this time was recorded, and the secondary battery was placed in a thermostatic box at 60°C and kept warm for 60 days (the battery was not operated during this period). After removal, the temperature was lowered to 25°C, and the secondary battery was discharged at a constant current of 1C to 2.8V. It was then charged at a constant current of 1C to 4.25V again, then charged to 0.05C at a constant voltage of 4.25V, allowed to stand for 10 minutes, and then discharged at a constant current of 1C to 2.8V. The discharge capacity D1 was recorded, and the high-temperature storage capacity retention rate of the secondary battery was calculated according to the following formula: High-temperature storage capacity retention rate of secondary battery = 100% × D1 / D0 (4) Impedance behavior test At 25°C, the secondary battery was left standing for 10 minutes, charged to 4.25 V at 1 C, further charged to 0.05 C at a constant voltage of 4.25 V, left standing for 30 minutes, discharged at 1 C for 30 minutes, left standing for 60 minutes, the voltage V1 at the end of the standing time was recorded, and then discharged at 4 C for 30 seconds, the voltage V2 at the end of the discharge was recorded, and the impedance of the battery at 50% SOC was calculated according to the following formula: I = 4 C. R=(V1-V2) / I (5) Measurement of electrolyte conductivity Conductivity tests of the electrolyte at room temperature (25 °C) were carried out according to HG-T 4067-2015.

[0103] Measurement results: The conductivity of the electrolytes of Examples 1 to 19 was in the range of 7 mS / cm to 15 mS / cm.

[0104] (6) Low-temperature freezing point measurement of electrolytes After the liquid was poured into the battery core, it was sealed, and the battery core was clamped with an expansion force test sensor, then placed in a high-temperature box and gradually cooled while monitoring the change in the expansion force of the battery core. When the electrolyte solidified, the expansion force of the battery core increased sharply, and the temperature corresponding to the turning point of the expansion force increase was recorded. This temperature was the freezing point of the electrolyte.

[0105] Measurement results: The low temperature freezing points of the electrolytes of Examples 1 to 19 at 1 standard atmospheric pressure were in the range of -80°C to -20°C.

[0106] The results of the above items (1) to (4) are shown in Table 2.

[0107] [Table 2] Secondary battery performance test results for Examples 1 to 19 and Comparative Examples 1 and 2 [Table 2]

[0108] As can be seen from Tables 1 and 2, Compared with Comparative Examples 1 and 2, the batteries manufactured using the electrolytes of Examples 1 to 19 of the present application have higher cycle capacity retention rates, lower volume expansion rates of the battery cores, and higher high-temperature storage capacity retention rates; Compared with Example 15, the mass content of the first additive in the electrolyte in Examples 1 to 5, 8, 11, 14, and 17 of the present application is 10 ppm to 3%, and the batteries manufactured therefrom have higher cycle capacity retention rates, higher high-temperature storage capacity retention rates, and lower impedance of the battery core; Compared with Example 10, Examples 2, 6 to 9, 11, 18 to 19 of the present application simultaneously use the first additive and the second additive, and the impedance of the battery core manufactured thereby is lower, the volume expansion rate of the battery core is lower, and the battery cycle capacity retention rate and high-temperature storage capacity retention rate are higher; Compared with Example 16, the mass content of the second additive in the electrolyte in Example 12 of the present application is 100 ppm to 2%, and the cycle capacity retention rate and high-temperature storage capacity retention rate of the battery manufactured therewith are higher; Compared with Examples 1, 5, 6, and 15, the ratio b / a of the mass content of the second additive to the mass content of the first additive in Examples 2 to 4, 7 to 9, 11, 13, 14, and 17 to 18 of the present application was within the range of 0.5 to 10, and the batteries manufactured therefrom had higher cycle capacity retention rates, higher high-temperature storage capacity retention rates, and lower impedances of the battery cores.

[0109] From the above, it has been explained that the battery manufactured using the electrolyte of the present application has a higher cycle capacity retention rate, a lower volume expansion rate of the battery core, a higher high-temperature storage capacity retention rate, and a lower impedance of the battery core.

[0110] It should be noted that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any embodiment that has substantially the same configuration as the technical idea and achieves the same effects within the scope of the technical solution of the present application is included within the technical scope of the present application. In addition, various modifications that a person skilled in the art can make to the embodiments and other methods that are constructed by combining some of the components of the embodiments are also included within the scope of the present application, as long as they do not deviate from the spirit of the present application. [Explanation of symbols]

[0111] 1 battery pack 2 Upper housing 3 Lower housing 4 Battery Module 5 Secondary battery 51 cases 52 Electrode Assembly 53 Cover plate

Claims

1. An electrolyte comprising a first additive according to formula (I): 【Chemical 1】 where: An electrolyte wherein R is one or more selected from halogen and MO-, and M is selected from alkali metals.

2. R is one or more selected from F and MO-, and / or M is one or more selected from lithium, sodium, potassium, rubidium, and cesium; Optionally, M is one or more selected from lithium, sodium, and potassium; Optionally, M is lithium.

3. the first additive is one or more selected from lithium sulfamate, aminosulfonyl fluoride, sodium sulfamate, and potassium sulfamate; Optionally, the first additive is one or more selected from lithium sulfamate and aminosulfonyl fluoride.

4. 4. The electrolyte according to claim 1, wherein the mass content of the first additive in the electrolyte is 3.5% or less, selectively 10 ppm to 3.5%, more selectively 10 ppm to 3%, even more selectively 500 ppm to 1%, and even more selectively 0.1% to 1%.

5. It further comprises a second additive shown in formula (II) or formula (III), 【Chemistry 2】 【Chemistry 3】 where: In formula (II) and formula (III), E is independently one or more selected from phosphorus and boron; In formula (II) and formula (III), each G is independently selected from halogen; and, when E is phosphorus, x is 2 and y is 2; When E in formula (II) is boron, x is 4 and y is 0, or x is 2 and y is 1; 5. The electrolyte of claim 1, wherein when E in formula (III) is boron, x is 4 and y is 0.

6. The electrolyte according to claim 5 , wherein each of the Gs in formula (II) and formula (III) is independently F.

7. the second additive is one or more selected from lithium difluorophosphate, lithium difluorobis(oxalato)phosphate, lithium tetrafluoroborate, and lithium difluoro(oxalato)borate; 7. The electrolyte according to claim 5 or 6, wherein the second additive is optionally one or more selected from lithium difluorophosphate, lithium tetrafluoroborate, and lithium difluoro(oxalato)borate.

8. The electrolyte according to any one of claims 5 to 7, wherein the mass content of the second additive in the electrolyte is 2.3% or less, selectively 100 ppm to 2.3%, more selectively 100 ppm to 2%, and further selectively 0.1% to 1%.

9. 9. The electrolyte according to claim 5, wherein the ratio of the mass content of the second additive in the electrolyte to the mass content of the first additive in the electrolyte is 0.1 to 500, optionally 0.5 to 12, and more optionally 0.5 to 10.

10. The electrolyte salt further comprises LiPF ６ , lithium bis(fluorosulfonyl)imide, lithium fluorosulfonate, lithium fluorosulfonyl(trifluoromethylsulfonyl)imide, and lithium bis(pentafluoroethylsulfonyl)imide; and optionally LiPF ６ 10. The electrolyte of claim 1, wherein the fluorocarbon is one or more selected from the group consisting of fluorocarbons, fluoroisopropyl ether ...

11. A battery comprising an electrolyte according to any one of claims 1 to 10.

12. A power consuming device comprising the battery of claim 11.

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