Electrolyte additive, electrolyte, battery and electric device

Abstract

An electrolyte additive, an electrolyte, a battery and an electric device. The electrolyte additive comprises vinylene carbonate, methylene methanedisulfonate and an alkynyl compound. The alkynyl compound comprises (I), wherein n is 0-10, and R comprises (II) or (III).

Description

Electrolyte additive, electrolyte, battery and electrical device

[0001] Priority information

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on November 1, 2023, with patent application number 202311447395.5 and entitled “Electrolyte Additives, Electrolytes, Batteries and Electrical Devices,” and the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application belongs to the field of batteries, and specifically relates to an electrolyte additive, an electrolyte, a battery, and an electrical device. Background Art

[0004] In recent years, as the application scope of batteries has become wider and wider, batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and other fields.

[0005] However, as the battery cycles, a thicker SEI film (solid electrolyte membrane) will form on the surface of the negative electrode, and the SEI film is prone to rupture and reorganization, resulting in lower cycle performance and power performance of the battery.

[0006] Summary of the Invention

[0007] In view of the technical problems existing in the background technology, the present application provides an electrolyte additive, aiming to improve the power performance and cycle performance of the battery.

[0008] In order to achieve the above-mentioned purpose, the first aspect of the present application proposes an electrolyte additive, vinylene carbonate, methylene methanedisulfonate and an alkynyl compound, wherein the alkynyl compound includes n is 0-10, R includes

[0009] The present application at least includes the following beneficial effects: the electrolyte additive of the present application can form a thin and dense SEI film with low interfacial impedance on the surface of the negative electrode, thereby improving the power performance and cycle performance of the battery containing the electrolyte additive.

[0010] In some embodiments, the mass ratio of the vinylene carbonate, the methylene methanedisulfonate, and the alkynyl compound is 1:0.1-10:0.1-5. This can improve the power performance and cycle performance of a battery containing the same.

[0011] In some embodiments, the mass ratio of the vinylene carbonate, the methylene methanedisulfonate, and the alkynyl compound is 1:0.5-3:0.5-2. Thus, the power performance and cycle performance of the battery containing the vinylene carbonate can be improved.

[0012] In some embodiments, the R comprises This can improve the power performance and cycle performance of batteries containing the same.

[0013] In some embodiments, the alkynyl compound comprises Thus, the power performance and cycle performance of the battery containing the same can be improved.

[0014] In some embodiments, the alkynyl compound comprises Thus, the power performance and cycle performance of the battery containing the same can be improved.

[0015] In a second aspect of the present application, the present application provides an electrolyte comprising the electrolyte additive described in the first aspect, thereby improving the power performance and cycle performance of a battery containing the electrolyte.

[0016] In some embodiments, the electrolyte additive accounts for 1% to 20% by weight based on the total mass of the electrolyte, thereby improving the power performance and cycle performance of the battery containing the electrolyte additive.

[0017] In some embodiments, the electrolyte additive accounts for 2% to 10% by weight based on the total mass of the electrolyte, thereby improving the power performance and cycle performance of the battery containing the electrolyte additive.

[0018] In some embodiments, the weight percentage of the vinylene carbonate is 0.5%-10% based on the total weight of the electrolyte, thereby improving the power performance and cycle performance of the battery containing the vinylene carbonate.

[0019] In some embodiments, the weight percentage of the vinylene carbonate is 1% to 5% based on the total weight of the electrolyte, thereby improving the power performance and cycle performance of the battery containing the vinylene carbonate.

[0020] In some embodiments, the weight proportion of the methylene methanedisulfonate is 0.1% to 8% based on the total weight of the electrolyte, thereby improving the power performance and cycle performance of the battery containing the methylene methanedisulfonate.

[0021] In some embodiments, the weight proportion of the methylene methanedisulfonate is 0.5% to 3% based on the total weight of the electrolyte, thereby improving the power performance and cycle performance of the battery containing the methylene methanedisulfonate.

[0022] In some embodiments, the mass proportion of the alkynyl compound is 0.1%-5% based on the total mass of the electrolyte, thereby improving the cycle performance of the battery containing the alkynyl compound.

[0023] In some embodiments, the mass proportion of the alkynyl compound is 0.5%-3% based on the total mass of the electrolyte, thereby improving the cycle performance of the battery containing the alkynyl compound.

[0024] In a third aspect of the present application, a battery is provided, comprising the electrolyte described in the second aspect, thereby having excellent power performance and cycle performance.

[0025] In a fourth aspect of the present application, the present application provides an electrical device comprising the battery described in the third aspect, thereby providing the battery with a longer service life.

[0026] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0028] FIG1 is a schematic diagram of a battery according to one embodiment of the present application.

[0029] FIG. 2 is an exploded view of the battery according to one embodiment of the present application shown in FIG. 1 .

[0030] FIG3 is a schematic diagram of a battery module according to an embodiment of the present application.

[0031] FIG4 is a schematic diagram of a battery pack according to an embodiment of the present application.

[0032] FIG. 5 is an exploded view of the battery pack shown in FIG. 4 according to an embodiment of the present application.

[0033] FIG6 is a schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application.

[0034] Description of reference numerals:

[0035] 1 battery cell; 11 shell; 12 electrode assembly; 13 cover plate; 2 battery module; 3 battery pack; 31 upper box; 32 lower box. DETAILED DESCRIPTION

[0036] The following embodiments of the technical solution of the present application are described in detail. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only used as examples and are not intended to limit the scope of protection of the present application.

[0037] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0038] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0039] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0040] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0041] Unless otherwise specified, all steps of the present 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 may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0042] Currently, market developments indicate that secondary batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As the application of secondary batteries continues to expand, market demand is also growing.

[0043] As the battery undergoes its first charge, the electrolyte and organic solvent in the electrolyte decompose, forming an SEI film composed of inorganic carbonates and organic matter on the surface of the negative electrode. This SEI film isolates the electrolyte from the negative electrode, thereby reducing side reactions between the negative electrode active material and the electrolyte and improving the battery's cycle performance. However, due to the continuous expansion and contraction of the negative electrode active material in the negative electrode, and the low toughness of the SEI film formed by inorganic carbonates and organic matter, the SEI film can rupture during cycling. As the cycling process continues, new SEI films continue to form on the surface of the negative electrode, meaning that the SEI film continuously ruptures and reorganizes during the cycling process, increasing organic solvent consumption. The decomposition of the organic solvent is accompanied by gas production, which increases battery gas production and reduces the battery's cycle life. Furthermore, the SEI film formed by inorganic carbonates and organic matter is thicker, increasing the battery's internal resistance and reducing its power performance.

[0044] The present application adopts an electrolyte additive including vinylene carbonate, methylene methanedisulfonate and alkynyl compounds, wherein methylene methanedisulfonate and vinylene carbonate can undergo a reduction reaction on the surface of the negative electrode before formation and during the initial charge and discharge to form a low interfacial impedance SEI film, thereby reducing the DC resistance of the battery and improving the power performance of the battery. At the same time, during the battery charging process, the alkynyl compound of the present application is reduced on the surface of the negative electrode to form an alkynyl radical, which can react with the double bond in vinylene carbonate to form a thin and dense copolymer on the surface of the negative electrode, which can prevent side reactions between the electrolyte and the negative electrode and improve gas production during battery cycling and storage. At the same time, the R group on the copolymer interacts with methylene methanedisulfonate to promote more uniform dispersion and film formation of methylene methanedisulfonate on the surface of the negative electrode, thereby forming a denser SEI film on the surface of the negative electrode. The SEI film is not easy to rupture, thereby reducing the consumption of organic solvents, further reducing battery gas production, and improving the cycle life of the battery.

[0045] The electrolyte additive disclosed in the embodiments of the present application is applicable to lithium-ion batteries and sodium-ion batteries, and the battery disclosed in the embodiments of the present application can be used in electrical equipment that uses the battery as a power source or various energy storage systems that use the battery as an energy storage element. Electrical equipment may include, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, battery cars, electric cars, ships, spacecraft, and the like. Among them, electric toys may include fixed or mobile electric toys, for example, game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like, and spacecraft may include airplanes, rockets, space shuttles, and spacecraft, and the like.

[0046] The first aspect of the present application provides an electrolyte additive, wherein the electrolyte additive comprises vinylene carbonate, methylene methanedisulfonate and an alkynyl compound, wherein the alkynyl compound comprises n is 0-10, R includes

[0047] The methylene disulfonate and vinylene carbonate in the electrolyte additive of the present application can undergo a reduction reaction on the surface of the negative electrode before formation and during the initial charge and discharge to form a SEI film with low interfacial impedance, thereby reducing the DC resistance of the battery and improving the power performance of the battery. At the same time, during the battery charging process, the alkynyl compound in the electrolyte additive is reduced on the surface of the negative electrode, and the formed alkynyl radical can react with the double bond in vinylene carbonate to form a thin and dense copolymer on the surface of the negative electrode, which can prevent the side reaction between the electrolyte and the negative electrode and improve the gas production during battery cycling and storage. At the same time, the R group on the copolymer interacts with methylene disulfonate to promote a more uniform dispersion of methylene disulfonate on the surface of the negative electrode and participate in film formation, thereby forming a denser SEI film on the surface of the negative electrode. The SEI film is not easy to rupture, thereby reducing the consumption of organic solvents, further reducing battery gas production, and improving the cycle life of the battery.

[0048] In some embodiments of the present application, the mass ratio of the vinylene carbonate, the methylene methanedisulfonate and the alkynyl compound is 1:0.1-10:0.1-5, for example, 1:0.3-10:0.1-5, 1:0.5-10:0.1-5, 1:0.7-10:0.1-5, 1:1-10:0.1-5, 1:2-8:0.1-5, 1:3-7:0.1-5, 1:4-6:0.1-5, 1:5-6:0.1-5, 1: 0.1-10:0.3-5, 1:0.1-10:0.5-5, 1:0.1-10:0.7-5, 1:0.1-10:1-5, 1:0.1-10:1.5-4.5, 1:0.1-10:2-4, 1:0.1-10:2.5-3.5, 1:0.1-10:2.5-3, etc. Thus, by mixing vinylene carbonate, methylene methanedisulfonate and alkynyl compound in the above proportions, not only can a low interfacial impedance SEI film be formed on the surface of the negative electrode, thereby reducing the DC resistance of the battery and improving the power performance of the battery, but the SEI film is also thin and dense, which can prevent side reactions between the electrolyte and the negative electrode, thereby reducing the consumption of organic solvents, improving gas generation during battery cycling and storage, and extending the cycle life of the battery. In some other embodiments of the present application, the mass ratio of the vinylene carbonate, the methylene methanedisulfonate and the alkynyl compound is 1:0.5-3:0.5-2.

[0049] In some embodiments of the present application, the alkynyl compound includes n is 0-10, for example, n can be 2-8, 4-6, 3-5, etc., and It can be a straight chain alkyl group or a branched chain alkyl group or a combination of straight chain and branched chain alkyl groups. R includes Thus, by using the alkynyl compound of the present invention, it can react with the double bonds in vinylene carbonate to form a thin and dense copolymer on the negative electrode surface. This copolymer can prevent side reactions between the electrolyte and the negative electrode, improving gas production during battery cycling and storage. At the same time, the R group on the copolymer interacts with methylene methanedisulfonate to promote more uniform dispersion and film formation of methylene methanedisulfonate on the negative electrode surface, thereby forming a denser SEI film on the negative electrode surface. This SEI film is less prone to rupture, thereby reducing organic solvent consumption, further reducing battery gas production, and improving the battery's cycle life.

[0050] It should be noted that the curved bond in the above R group " " refers to the connection site on the molecular structure, i.e., substitution The attachment site of R in the structure.

[0051] In some embodiments of the present application, the The R on Therefore, by introducing the above-mentioned R group into the alkynyl compound, not only can the more uniform dispersion and film formation of methylene disulfonate on the negative electrode surface be promoted, thereby forming a denser SEI film on the negative electrode surface, the SEI film is not easy to rupture, thereby reducing the consumption of organic solvents, further reducing battery gas production, and improving the cycle life of the battery; but also the ionic conductivity of the SEI film can be improved, thereby improving the power performance of the battery.

[0052] In some embodiments of the present application, the alkynyl compound includes (CAS No.: 16156-58-4), (CAS No. 7651-65-2), (CAS No.: 61764-71-4), (CAS No.: 922-67-8), (CAS No.: 13861-22-8), (CAS No.: 13361-64-3), (CAS No.: 1066-54-2), (CAS No. 5582-62-7) (CAS No.: 35161-71-8), (CAS No.: 898544-65-5), (CAS No. 35718-08-2) or (CAS No.: 1233816-83-5). Thus, by adopting the alkynyl compound of the present application, it can react with the double bond in vinylene carbonate to form a thin and dense copolymer on the surface of the negative electrode, which can prevent the side reaction between the electrolyte and the negative electrode, and improve the gas production during battery circulation and storage. At the same time, the R group on the copolymer interacts with methylene disulfonate to promote a more uniform dispersion of methylene disulfonate on the surface of the negative electrode and participate in film formation, thereby forming a denser SEI film on the surface of the negative electrode. The SEI film is not easy to rupture, thereby reducing the consumption of organic solvents, further reducing battery gas production, and improving the cycle life of the battery. In other embodiments of the present application, the alkynyl compound includes Thus, by using this type of alkynyl compound, not only can the more uniform dispersion of methylene methanedisulfonate on the negative electrode surface and its participation in film formation be promoted, thereby forming a denser SEI film on the negative electrode surface, the SEI film is less likely to rupture, thereby reducing the consumption of organic solvents, further reducing battery gas production, and improving the cycle life of the battery; but the ionic conductivity of the SEI film can also be increased, thereby improving the power performance of the battery.

[0053] In the second aspect of the present application, the present application proposes an electrolyte comprising the electrolyte additive described in the first aspect above. Thus, methylene disulfonate and vinylene carbonate in the electrolyte additive can undergo a reduction reaction on the surface of the negative electrode before formation and during the initial charge and discharge period, forming a low interfacial impedance SEI film, thereby reducing the DC resistance of the battery and improving the power performance of the battery. At the same time, during the battery charging process, the alkynyl compound in the electrolyte additive is reduced on the surface of the negative electrode, and the alkynyl radicals formed can react with the double bonds in the vinylene carbonate to form a thin and dense copolymer on the surface of the negative electrode, which can prevent side reactions between the electrolyte and the negative electrode and improve gas production during battery cycling and storage. At the same time, the R group on the copolymer interacts with methylene disulfonate to promote more uniform dispersion and film formation of methylene disulfonate on the surface of the negative electrode, thereby forming a denser SEI film on the surface of the negative electrode. This SEI film is less likely to rupture, thereby reducing the consumption of organic solvents, further reducing battery gas production, and improving the cycle life of the battery.

[0054] In some embodiments of the present application, based on the total mass of the electrolyte, the weight proportion of the electrolyte additive is 1%-20%, for example, 1.5%-18%, 2%-15%, 2.5%-15%, 3%-13%, 3.5%-10%, 4%-8%, 4.5%-6%, 4.5%-5%, etc. Thus, by adding the above-mentioned content of the electrolyte additive to the electrolyte, not only can a low interfacial impedance SEI film be formed on the surface of the negative electrode, thereby reducing the DC resistance of the battery and improving the power performance of the battery, but the SEI film is also thin and dense, thereby reducing the consumption of organic solvents, which can prevent side reactions between the electrolyte and the negative electrode, improve gas production during battery cycling and storage, and increase the cycle life of the battery. In other embodiments of the present application, based on the total mass of the electrolyte, the weight proportion of the electrolyte additive is 2%-10%. Thus, the power performance and cycle performance of the battery containing it can be improved.

[0055] In some embodiments of the present application, the mass proportion of the vinylene carbonate based on the total mass of the electrolyte is 0.5%-10%, such as 1%-10%, 1.5%-9.5%, 2%-9%, 2.5%-8.5%, 3%-8%, 3.5%-7.5%, 4%-7%, 4.5%-6.5%, 5%-6%, 5.5%-6%, etc. Thus, by adding the above-mentioned content of vinylene carbonate to the electrolyte, not only can a low interfacial impedance SEI film be formed on the surface of the negative electrode, thereby reducing the DC resistance of the battery and improving the power performance of the battery, but the SEI film is also thin and dense, thereby reducing the consumption of organic solvents, which can prevent side reactions between the electrolyte and the negative electrode, improve gas production during battery cycling and storage, and increase the cycle life of the battery. In some embodiments of the present application, the mass proportion of the vinylene carbonate based on the total mass of the electrolyte is 1%-5%. Thus, the power performance and cycle performance of the battery containing it can be improved.

[0056] In some embodiments of the present application, based on the total mass of the electrolyte, the weight proportion of the methylene methanedisulfonate is 0.1%-8%, such as 0.3%-8%, 0.5%-8%, 0.7%-8%, 1%-8%, 1.5%-7.5%, 2%-7%, 2.5%-6.5%, 3%-6%, 3.5%-5.5%, 4%-5%, 4.5%-5%, etc. Thus, by adding the above-mentioned content of methylene methanedisulfonate to the electrolyte, not only can a low interfacial impedance SEI film be formed on the surface of the negative electrode, thereby reducing the DC resistance of the battery and improving the power performance of the battery, but the SEI film is thin and dense, thereby reducing the consumption of organic solvents, which can prevent side reactions between the electrolyte and the negative electrode, improve gas production during battery cycling and storage, and increase the cycle life of the battery. In other embodiments of the present application, based on the total mass of the electrolyte, the weight proportion of the methylene methanedisulfonate is 0.5%-3%. This can improve the power performance and cycle performance of batteries containing the same.

[0057] In some embodiments of the present application, based on the total mass of the electrolyte, the mass proportion of the alkynyl compound is 0.1%-5%, for example, 0.3%-5%, 0.5%-5%, 0.7%-5%, 1%-5%, 1.5%-4.5%, 2%-4%, 2.5%-3.5%, 3%-3.5%, etc. Thus, by adding the above-mentioned content of the alkynyl compound to the electrolyte, not only a thin and dense copolymer can be formed on the surface of the negative electrode, but it can also prevent side reactions between the electrolyte and the negative electrode, improve gas production during battery cycling and storage, and increase the cycle life of the battery. In other embodiments of the present application, based on the total mass of the electrolyte, the mass proportion of the alkynyl compound is 0.5%-3%. Thus, the cycle performance of the battery containing it can be improved.

[0058] In some embodiments of the present application, the electrolyte further includes an electrolyte salt and a solvent.

[0059] In some embodiments of the present application, when the battery is a lithium ion battery, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate or lithium tetrafluorooxalatophosphate.

[0060] In some embodiments of the present application, when the battery is a sodium ion battery, the electrolyte salt may include at least one of sodium hexafluorophosphate, sodium difluorooxalatoborate, sodium tetrafluoroborate, sodium bisoxalatoborate, sodium perchlorate, sodium hexafluoroarsenate, sodium bis(fluorosulfonyl)imide, sodium trifluoromethylsulfonate or sodium bis(trifluoromethylsulfonyl)imide.

[0061] In some embodiments of the present application, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, ethylene glycol dimethyl ether, methyl ethyl sulfone or diethyl sulfone.

[0062] In some embodiments of the present application, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, and additives that improve battery high or low temperature performance.

[0063] In a third aspect of the present application, a battery is provided, comprising the electrolyte described in the second aspect, thereby having excellent power performance and cycle performance.

[0064] Typically, a battery consists of a positive electrode, a negative electrode, an electrolyte, and a separator. During the battery's charge and discharge processes, active ions are inserted and removed between the positive and negative electrodes. The electrolyte conducts ions between the positive and negative electrodes. The separator, located between the positive and negative electrodes, primarily prevents short circuits between the positive and negative electrodes while allowing ions to pass through.

[0065] In a battery, the positive electrode sheet generally includes a positive electrode current collector and a positive electrode active material layer, wherein the positive electrode active material layer is disposed on at least one side of the positive electrode current collector.

[0066] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0067] In some embodiments of the present application, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0068] In some embodiments of the present application, the positive electrode active material layer includes a positive electrode active material. The specific type of the positive electrode active material is not limited. Active materials known in the art that can be used for battery positive electrodes can be used. Those skilled in the art can select according to actual needs.

[0069] As an example, when the positive electrode plate is used in a lithium-ion battery, the positive electrode active material may adopt a positive electrode active material for lithium-ion batteries that is well known in the art. As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.8 Co 0.15 Al 0.05 O2) or at least one of its modified compounds. Examples of olivine-structured lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, or a composite material of lithium iron manganese phosphate and carbon.

[0070] For example, when the positive electrode plate is used in a sodium ion battery, the positive electrode active material may be a positive electrode active material known in the art for use in sodium ion batteries. For example, the positive electrode active material may include, but is not limited to, at least one of a layered transition metal oxide, a polyanion compound, and a Prussian blue analog.

[0071] Examples of the layered transition metal oxides include:

[0072] Na 1-x Cu h Fe k Mn l M 1 m O 2-y , where M 1 Including at least one of Li, Be, B, Mg, Al, K, Ca, Ti, Co, Ni, Zn, Ga, Sr, Y, Nb, Mo, In, Sn or 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;

[0073] Na 0.67 Mn 0.7 Ni z M 2 0.3-z O2, where M 2 including at least one of Li, Mg, Al, Ca, Ti, Fe, Cu, Zn or Ba, 0 <z≤0.1;

[0074] Na a Li b Ni c Mn d Fe e O2, of which 0.67 <a≤1,0<b<0.2,0<c<0.3,0.67<d+e<0.8,b+c+d+e=1。

[0075] Examples of the polyanionic compound include:

[0076] A 1 f M 3 g (PO4) i O j X 1 3-j , where A 1 including at least one of H, Li, Na, K or NH4, M 3comprising at least one of Ti, Cr, Mn, Fe, Co, Ni, V, Cu or Zn, X 1 is at least one of F, Cl or Br, 0 < f ≤ 4, 0 < g ≤ 2, 1 ≤ i ≤ 3, 0 ≤ j ≤ 2;

[0077] Na n M 4 PO4X 2 , wherein M 4 comprises at least one of Mn, Fe, Co, Ni, Cu or Zn, X 2 is at least one of F, Cl or Br, 0 < n ≤ 2;

[0078] Na p M 5 q (SO4)3, wherein M 5 comprises at least one of Mn, Fe, Co, Ni, Cu or Zn, 0 < p ≤ 2, 0 < q ≤ 2;

[0079] Na s Mn t Fe 3-t (PO4)2(P2O7), wherein 0 < s ≤ 4, 0 ≤ t ≤ 3, for example t is 0, 1, 1.5, 2 or 3.

[0080] As an example of the above Prussian blue analogs, for example, the following can be listed:

[0081] A u M 6 v [M 7 (CN)6] w ·xH2O, wherein A comprises H + , NH4 + , at least one of alkali metal cations or alkaline earth metal cations, M 6 and M 7 each independently comprise at least one of transition metal cations, 0 < u ≤ 2, 0 < v ≤ 1, 0 < w ≤ 1, 0 < x < 6. For example, A comprises H + , Li + , Na + , K + , NH4 + , Rb + , Cs + , Fr + , Be 2+ , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ or Ra 2+At least one of M 6 and M 7 Each independently includes at least a cation of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, or W.

[0082] The battery's charge and discharge processes are accompanied by the intercalation and deintercalation of Li or Na, and the molar content of Li or Na varies when the battery is discharged to different states. The molar content of Li or Na in the positive electrode materials listed in this application refers to the material's initial state, i.e., the state before the materials are added. When the positive electrode material is used in a battery system, the molar content of Li or Na will change after charge and discharge cycles.

[0083] In the list of positive electrode materials in this application, the molar content of oxygen is only a theoretical value. Lattice oxygen release will cause the molar content of oxygen to change, and the actual molar content of oxygen will fluctuate.

[0084] In some embodiments of the present application, the positive electrode active material layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, or a fluorine-containing acrylate resin.

[0085] In some embodiments of the present application, the positive electrode active material layer may further optionally include a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers.

[0086] In some embodiments, the positive electrode sheet can be prepared by the following method: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0087] In some embodiments of the present application, the negative electrode plate includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, and the negative electrode active material layer includes a negative electrode active material.

[0088] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material layer is provided on either one or both of the two facing surfaces of the negative electrode current collector.

[0089] In some embodiments of the present application, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base material. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer base material (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0090] In some embodiments of the present application, the negative electrode active material may adopt the negative electrode active material for batteries known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials and lithium titanate, etc. The silicon-based material may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites or silicon alloys. The tin-based material may include at least one of elemental tin, tin oxide compounds or tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0091] In some embodiments of the present application, the negative electrode active material layer may further optionally include a binder. The binder may include 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), or carboxymethyl chitosan (CMCS).

[0092] In some embodiments of the present application, the negative electrode active material layer may further include a conductive agent, which may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers.

[0093] In some embodiments of the present application, the negative electrode active material layer may optionally further include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0094] In some embodiments of the present application, the negative electrode sheet can be prepared by the following method: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0095] The present application has no particular limitation on the type of isolation membrane, and any known isolation membrane with a porous structure having good chemical stability and mechanical stability can be selected.

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

[0097] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator can be formed into an electrode assembly through a winding process or a lamination process.

[0098] In some embodiments, the secondary battery may include an outer packaging that can be used to encapsulate the electrode assembly and the electrolyte.

[0099] In some embodiments, the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. Alternatively, the outer packaging of the secondary battery can be a soft shell, such as a pouch-type soft shell. The soft shell can be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0100] The present application has no particular limitation on the shape of the battery, which can be cylindrical, square, or any other shape. For example, FIG1 shows a battery cell 1 with a square structure as an example.

[0101] In some embodiments, referring to Figure 2, the outer packaging may include a shell 11 and a cover plate 13. The shell 11 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 11 has an opening connected to the receiving cavity, and the cover plate 13 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can form an electrode assembly 12 through a winding process or a lamination process. The electrode assembly 12 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 12. The number of electrode assemblies 12 contained in the battery cell 1 can be one or more, and those skilled in the art can select according to specific actual needs.

[0102] In some embodiments, batteries may be assembled into a battery module. The number of batteries contained in the battery module may be one or more. The specific number may be selected by those skilled in the art based on the application and capacity of the battery module.

[0103] Figure 3 shows an example battery module 2. Referring to Figure 3 , within the battery module 2, multiple battery cells 1 may be arranged sequentially along the length of the battery module 2. Of course, they may also be arranged in any other manner. Furthermore, the multiple battery cells 1 may be secured together using fasteners.

[0104] Optionally, the battery module 2 may further include a housing having an accommodation space, and the plurality of battery cells 1 are accommodated in the accommodation space.

[0105] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art based on the application and capacity of the battery pack.

[0106] Figures 4 and 5 illustrate an example battery pack 3. Referring to Figures 6 and 7 , the battery pack 3 may include a battery box and multiple battery modules 2 disposed within the box. The battery box comprises an upper case 31 and a lower case 32. The upper case 31 can be placed over the lower case 32 to form an enclosed space for accommodating the battery modules 2. The multiple battery modules 2 can be arranged in any manner within the battery box.

[0107] In addition, the present application also provides an electric device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application. The secondary battery, battery module, or battery pack can be used as a power source for the electric device, and can also be used as an energy storage unit for the electric device. The electric device may include mobile devices (such as mobile phones, laptops, etc.), electric 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., but is not limited thereto.

[0108] As the electrical device, a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.

[0109] Figure 6 shows an example of an electric device. This device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the secondary battery, a battery pack or battery module can be used.

[0110] Another example device may be a mobile phone, a tablet computer, a laptop computer, etc. Such a device is usually required to be light and thin, and may use a battery as a power source.

[0111] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0112] Example 1

[0113] (1) Preparation of electrolyte

[0114] Vinylene carbonate, methylene methanedisulfonate and propargyl methanesulfonate (Formula 1) are mixed in a mass ratio of 1:1:1 to obtain an electrolyte additive, and then ethylene carbonate, diethyl carbonate and dimethyl carbonate are mixed in a mass ratio of 1:1:1 to obtain an organic solvent, which is then mixed with LiPF6 and mixed evenly to obtain a basic electrolyte. The above-mentioned electrolyte additive is added to the basic electrolyte to obtain an electrolyte, wherein the mass ratios of vinylene carbonate, methylene methanedisulfonate and propargyl methanesulfonate are 2%, 2% and 2%, respectively, based on the total amount of the electrolyte as 100%.

[0115] (2) Preparation of positive electrode sheet

[0116] Lithium iron phosphate, binder PVDF, and conductive agent acetylene black were added to N-methylpyrrolidone solvent in a mass ratio of 95:3:2, and stirred evenly to prepare the positive electrode slurry. The positive electrode slurry was coated on both sides of the current collector aluminum foil, dried, and cold pressed to obtain positive electrode sheets.

[0117] (3) Preparation of negative electrode sheet

[0118] Artificial graphite, conductive carbon black, thickener sodium carboxymethyl cellulose, and binder styrene-butadiene rubber are added to deionized water in a mass ratio of 95:1:2:2, stirred evenly to obtain a negative electrode slurry, coated on a current collector copper foil, dried, and cold pressed to obtain negative electrode sheets.

[0119] (4) Isolation film

[0120] Polyethylene film is used as the isolation film.

[0121] (5) Preparation of lithium-ion batteries

[0122] The positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator placed between the positive and negative electrode sheets to serve as an isolation, and then wound to obtain an electrode assembly; the electrode assembly is placed in an outer package, and the prepared electrolyte is injected into the dried lithium-ion battery. After vacuum packaging, standing, formation, and shaping processes, a lithium-ion battery is obtained.

[0123] The difference between Examples 2-41 and Comparative Examples 1-4 and Example 1 is that the composition and content of the electrolyte additives in the electrolyte are different, see Table 1 for details. The other steps are the same as in Example 1 to prepare lithium-ion batteries.

[0124] Table 1

[0125] The lithium ion cycle performance, storage performance, power performance and gas production obtained in the above Examples 1-41 and Comparative Examples 1-4 were characterized, as shown in Table 2.

[0126] (1) Lithium-ion battery cycle performance test

[0127] The ambient temperature was controlled at 25°C. The battery was charged to 3.65V at 1C, then charged to 0.05C at a constant voltage, left to stand for 5 minutes, and then discharged to 2.5V at 1C. The discharge capacity was recorded as C0. 600 cycles were performed according to the above charge and discharge process. The discharge capacity at the 600th cycle was C1, and the cycle capacity retention rate = C1 / C0*100%.

[0128] The ambient temperature was controlled at 60°C. The battery was charged to 3.65V at 1C, then charged to 0.05C at a constant voltage, left to stand for 5 minutes, and then discharged to 2.5V at 1C. The discharge capacity was recorded as C2. 500 cycles were performed according to the above charge and discharge process. The discharge capacity at the 500th cycle was C3, and the cycle capacity retention rate = C3 / C2*100%.

[0129] (2) Lithium-ion battery storage performance test

[0130] The battery was charged to 3.65V at 1C at an ambient temperature of 25°C, then charged to 0.05C at a constant voltage and allowed to rest for 5 minutes (recorded as a full charge cycle). The battery was then discharged to 2.0V at 1C (recorded as a full discharge cycle). The discharge capacity after the full discharge cycle was recorded as C4. A full charge cycle was repeated to reach 100% SOC. The battery was then stored at 60°C for 30 days. After 30 days, the ambient temperature was returned to 25°C, and the full discharge and full charge cycles were repeated. The battery was then discharged to 2.0V at 1C and allowed to rest for 5 minutes. The discharge capacity was recorded as C5. Storage capacity retention = C5 / C4 * 100%.

[0131] (3) Power performance test

[0132] The battery was charged to 3.65V at 1C, then charged to 0.05C at constant voltage, allowed to rest for 5 minutes, then discharged at 1C for 0.5h, allowed to rest for 60 minutes, and the voltage V1 after rest was recorded. The battery was then discharged at 2C for 30s with a sampling interval of 0.1s, and the voltage V2 at the end of discharge was recorded. The battery DCR (DC internal resistance) = (V1-V2) / I, I = 2C.

[0133] (4) Gas production test

[0134] The battery was charged at 1C to 3.65V at a controlled ambient temperature of 25°C, then charged at a constant voltage to 0.05C and left to rest for 5 minutes (this is considered a full charge cycle). The battery was then discharged at 1C to 2.0V (this is considered a full discharge cycle). The battery was fully charged again to 100% SOC, and its volume was measured and recorded as the volume before storage. The battery was then stored at 60°C for 30 days. After 30 days, the battery was removed and placed in a 25°C environment, and its volume was measured.

[0135] Gas production (ml) of the battery after storage at 60°C for 30 days = volume of the battery after storage for 30 days - volume of the battery before storage.

[0136] Table 2

[0137] Conclusion: Comparing Examples 1-41 and Comparative Examples 1-4 in Table 1, the electrolyte additives used in Examples 1-41 include vinylene carbonate, methylene methanedisulfonate, and an alkynyl compound, while the electrolyte additives of Comparative Example 1 include only vinylene carbonate, the electrolyte additives of Comparative Example 2 include only vinylene carbonate and methylene methanedisulfonate, the electrolyte additives of Comparative Example 3 include only vinylene carbonate and an alkynyl compound, and the electrolyte additives of Comparative Example 4 include only methylene methanedisulfonate and an alkynyl compound. As can be seen from Table 2, the batteries of Examples 1-41 have excellent overall performance compared to Comparative Examples 1-4. Although Examples 34 and 41 have slightly lower capacity retention rates than Comparative Examples 1-2 and 4, the batteries of Examples 34 and 41 have lower DCRs. Although the battery of Comparative Example 4 has excellent capacity retention and lower gas production, its DCR is larger. Comparison of Examples 19-24 with Comparative Example 4 shows that the batteries of Examples 19-24 have higher capacity retention rates; comparison of Examples 25-29 with Comparative Example 3 shows that the batteries of Examples 25-29 have lower DCRs; comparison of Examples 30-33 with Comparative Example 2 shows that the batteries of Examples 30-33 have higher capacity retention rates and lower gas production. This demonstrates that the electrolyte additive comprising vinylene carbonate, methylene methanedisulfonate, and an alkynyl compound of the present application can simultaneously improve both the power performance and the cycle performance of the battery, i.e., the battery of the present application has excellent overall performance.

[0138] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. An electrolyte additive, characterized in that: include: Vinylene carbonate, methylene methanedisulfonate and an alkynyl compound, the alkynyl compound comprising n is 0-10, R includes 2. The electrolyte additive according to claim 1, characterized in that: The mass ratio of the vinylene carbonate, the methylene methanedisulfonate and the alkynyl compound is 1:0.1-10:0.1-5.

3. The electrolyte additive according to claim 1 or 2, characterized in that: The mass ratio of the vinylene carbonate, the methylene methanedisulfonate and the alkynyl compound is 1:0.5-3:0.5-2.

4. The electrolyte additive according to any one of claims 1 to 3, characterized in that: The R includes 5. The electrolyte additive according to any one of claims 1 to 4, characterized in that: The alkynyl compounds include At least one of .

6. The electrolyte additive according to any one of claims 1 to 5, characterized in that: The alkynyl compounds include At least one of .

7. An electrolyte, characterized in that: The electrolyte additive comprises the electrolyte additive described in any one of claims 1 to 6.

8. The electrolyte according to claim 7, characterized in that Based on the total mass of the electrolyte, the weight proportion of the electrolyte additive is 1%-20%.

9. The electrolyte according to claim 7 or 8, characterized in that Based on the total mass of the electrolyte, the weight proportion of the electrolyte additive is 2%-10%.

10. The electrolyte according to any one of claims 7 to 9, characterized in that: Based on the total mass of the electrolyte, the mass proportion of the vinylene carbonate is 0.5%-10%.

11. The electrolyte according to any one of claims 7 to 10, characterized in that: Based on the total mass of the electrolyte, the mass proportion of the vinylene carbonate is 1%-5%.

12. The electrolyte according to any one of claims 7 to 11, characterized in that: Based on the total mass of the electrolyte, the weight proportion of the methylene methanedisulfonate is 0.1%-8%.

13. The electrolyte according to any one of claims 7 to 12, characterized in that: Based on the total mass of the electrolyte, the weight proportion of the methylene methanedisulfonate is 0.5%-3%.

14. The electrolyte according to any one of claims 7 to 13, characterized in that: Based on the total mass of the electrolyte, the mass proportion of the alkynyl compound is 0.1%-5%.

15. The electrolyte according to any one of claims 7 to 14, characterized in that: Based on the total mass of the electrolyte, the mass proportion of the alkynyl compound is 0.5%-3%.

16. A battery, characterized in that: The invention comprises the electrolyte according to any one of claims 7 to 15.

17. An electrical device, characterized in that: Comprising the battery of claim 16.

Images