Electrolyte additive, electrolyte, battery and electric device

Abstract

Disclosed are an electrolyte additive, an electrolyte, a battery, and an electric device, the electrolyte additive including vinylene carbonate, methylene methanedisulfonate, and an alkynyl compound, the alkynyl compound including # imgabs 0 # n being 0-10, and R including # imgabs 1 # imgabs 2 # imgabs 3 #. The electrolyte additive disclosed by the invention can form a thin and compact SEI film with low interface impedance on the surface of a negative electrode, so that the power performance and the cycle performance of a battery containing the electrolyte additive are improved.

Description

Technical Field

[0001] 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

[0002] In recent years, as the application scope of batteries becomes wider and wider, batteries are widely used in energy storage power supply 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.

[0003] 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. Summary of the invention

[0004] In view of the technical problems existing in the background technology, the present application provides an electrolyte additive, aiming to improve the battery power performance and cycle performance.

[0005] In order to achieve the above-mentioned object, the first aspect of the present application proposes an electrolyte additive, vinylene carbonate, methylene methane disulfonate and an alkynyl compound, wherein the alkynyl compound comprises n is 0-10, R includes

[0006] 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.

[0007] In some embodiments, the mass ratio of the vinylene carbonate, the methylene methane disulfonate and the alkynyl compound is 1:0.1-10:0.1-5, and can be 1:0.5-3:0.5-2. Thus, the power performance and cycle performance of the battery containing the same can be improved.

[0008] In some embodiments, the R comprises Thus, the power performance and cycle performance of the battery containing the same can be improved.

[0009] In some embodiments, the alkynyl compound comprises

[0010]

[0011] At least one of, optionally, including Thus, the power performance and cycle performance of the battery containing the same can be improved.

[0012] In the second aspect of the present application, the present application proposes 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 additive.

[0013] In some embodiments, based on the total mass of the electrolyte, the weight proportion of the electrolyte additive is 1%-20%, and optionally 2%-10%, thereby improving the power performance and cycle performance of the battery containing the electrolyte additive.

[0014] In some embodiments, based on the total mass of the electrolyte, the mass proportion of the vinylene carbonate is 0.5%-10%, and optionally 1%-5%, thereby improving the power performance and cycle performance of the battery containing the vinylene carbonate.

[0015] In some embodiments, based on the total mass of the electrolyte, the weight proportion of the methylene methanedisulfonate is 0.1%-8%, and optionally 0.5%-3%, thereby improving the power performance and cycle performance of the battery containing the methylene methanedisulfonate.

[0016] In some embodiments, based on the total mass of the electrolyte, the mass proportion of the alkynyl compound is 0.1%-5%, and optionally 0.5%-3%, thereby improving the cycle performance of the battery containing the alkynyl compound.

[0017] In the third aspect of the present application, the present application provides a battery, comprising the electrolyte described in the second aspect, so that the battery has excellent power performance and cycle performance.

[0018] In a fourth aspect of the present application, the present application provides an electrical device, comprising the battery described in the third aspect, so that the battery has a longer service life.

[0019] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0021] Figure 1 is a schematic diagram of a battery according to one embodiment of the present application.

[0022] Figure 2 yes Figure 1 An exploded view of a battery according to an embodiment of the present application is shown.

[0023] Figure 3 is a schematic diagram of a battery module according to an embodiment of the present application.

[0024] Figure 4 It is a schematic diagram of a battery pack according to one embodiment of the present application.

[0025] Figure 5 yes Figure 4 An exploded view of a battery pack according to an embodiment of the present application is shown.

[0026] Figure 6 Schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application.

[0027] Description of reference numerals:

[0028] 1 battery cell; 11 shell; 12 electrode assembly; 13 cover plate; 2 battery module; 3 battery pack; 31 upper box body; 32 lower box body. DETAILED DESCRIPTION

[0029] The following is a detailed description of the embodiments of the technical solution of the present application. 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 cannot be used to limit the scope of protection of the present application.

[0030] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0031] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a 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 a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present 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 real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it 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.

[0032] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0033] 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.

[0034] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means 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), which means 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.

[0035] At present, from the perspective of market development, the application of secondary batteries is becoming more and more extensive. Secondary batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of secondary batteries, the market demand is also constantly expanding.

[0036] As the battery is charged for the first time, the electrolyte and organic solvent in the electrolyte will decompose and form a SEI film including inorganic carbonates and organic matter on the surface of the negative electrode. The SEI film can isolate the electrolyte from the negative electrode, thereby reducing the side reaction between the negative electrode active material and the electrolyte and improving the battery's cycle performance. However, due to the continuous expansion / 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 will rupture during the cycle. As the cycle process continues, a new SEI film will continue to form on the surface of the negative electrode, that is, the SEI film will continue to rupture and reorganize during the cycle, increasing the consumption of organic solvents, and the decomposition of organic solvents is accompanied by gas production, that is, the battery gas production is increased, reducing the battery's cycle life. And the SEI film formed by inorganic carbonates and organic matter is thicker, which increases the internal resistance of the battery and reduces the power performance of the battery.

[0037] The present application adopts an electrolyte additive including vinyl carbonate, methylene disulfonate and alkynyl compounds, wherein methylene disulfonate and vinyl carbonate can undergo 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 compounds of the present application are reduced on the surface of the negative electrode to form alkynyl radicals, which can react with the double bonds in vinyl 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 the more uniform dispersion and participation of methylene disulfonate on the surface of the negative electrode, thereby forming a denser SEI film on the surface of the negative electrode, and 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.

[0038] The electrolyte additive disclosed in the embodiments of the present application is suitable for lithium-ion batteries and sodium-ion batteries, and the battery disclosed in the embodiments of the present application can be used in electrical equipment using the battery as a power source or various energy storage systems using the battery as an energy storage element. Electrical equipment may include, but is not limited to, mobile phones, tablets, laptops, electric toys, electric 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, electric airplane toys, and the like, and spacecraft may include airplanes, rockets, space shuttles, and spacecraft, and the like.

[0039] In a first aspect, the present application provides an electrolyte additive, wherein the electrolyte additive comprises vinylene carbonate, methylene methane disulfonate and an alkynyl compound, wherein the alkynyl compound comprises n is 0-10, R includes

[0040] 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 circulation and storage. At the same time, the R group on the copolymer interacts with methylene disulfonate to promote the more uniform dispersion and participation of methylene disulfonate on the surface of the negative electrode, thereby forming a more dense SEI film on the surface of the negative electrode, and 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.

[0041] In some embodiments of the present application, the mass ratio of the vinylene carbonate, the methylene methane disulfonate 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. Therefore, by mixing vinylene carbonate, methylene methane disulfonate and alkynyl compound according to the above ratio, not only can a SEI film with low interfacial impedance 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 also the SEI film is thin and dense, which can prevent the side reaction between the electrolyte and the negative electrode, thereby reducing the consumption of organic solvents, improving the gas production during battery circulation and storage, and increasing 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.

[0042] 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 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 the 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, and 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.

[0044] It should be noted that the bent bonds in the above R groups Refers to the connection site on the molecular structure, that is, substitution The attachment site of R in the structure.

[0045] 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.

[0046] 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 composition of the present application, it can react with the double bonds 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 the battery cycle and storage process. 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 adopting such alkynyl compounds, not only can the more uniform dispersion of methylene disulfonate 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 not easy to rupture, thereby reducing the consumption of organic solvents, further reducing the gas production of the battery, 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.

[0050] In the second aspect of the present application, the present application proposes an electrolyte, the 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 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 the battery cycle and storage process. At the same time, the R group on the copolymer interacts with methylene disulfonate to promote the more uniform dispersion and participation of methylene disulfonate on the surface of the negative electrode, thereby forming a denser SEI film on the surface of the negative electrode, and 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.

[0051] 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%, such as 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 SEI film with low interfacial impedance 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 also the SEI film is thin and dense, thereby reducing the consumption of organic solvents, which can prevent the side reaction between the electrolyte and the negative electrode, improve the gas production during the battery cycle and storage process, 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.

[0052] In some embodiments of the present application, based on the total mass of the electrolyte, the mass proportion of the vinylene carbonate 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 SEI film with low interfacial impedance 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 also the SEI film is thin and dense, thereby reducing the consumption of organic solvents, which can prevent the side reaction between the electrolyte and the negative electrode, improve the gas production during the battery cycle and storage process, and increase the cycle life of the battery. In some embodiments of the present application, based on the total mass of the electrolyte, the mass proportion of the vinylene carbonate is 1%-5%. Thus, the power performance and cycle performance of the battery containing it can be improved.

[0053] In some embodiments of the present application, based on the total mass of the electrolyte, the weight proportion of the methylene disulfonate 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 disulfonate to the electrolyte, not only can a SEI film with low interface impedance 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 also the SEI film is thin and dense, thereby reducing the consumption of organic solvents, which can prevent the side reaction between the electrolyte and the negative electrode, improve the gas production during the battery cycle and storage process, 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 disulfonate is 0.5%-3%. Thus, the power performance and cycle performance of the battery containing the same can be improved.

[0054] 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%, such as 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 the side reaction between the electrolyte and the negative electrode, improve the gas production during the battery cycle 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.

[0055] In some embodiments of the present application, the electrolyte further includes an electrolyte salt and a solvent.

[0056] 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.

[0057] 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.

[0058] 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, methyl propyl carbonate, ethyl propyl 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 sulfone, dimethyl sulfone, ethylene glycol dimethyl ether, methyl ethyl sulfone or diethyl sulfone.

[0059] In some embodiments of the present application, the electrolyte may further include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.

[0060] In the third aspect of the present application, the present application provides a battery, comprising the electrolyte described in the second aspect, so that the battery has excellent power performance and cycle performance.

[0061] Typically, a battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte, and a separator. During the battery charge and discharge process, active ions are embedded and removed back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet. The separator is set between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.

[0062] In a battery, the positive electrode sheet generally includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is disposed on at least one side of the positive electrode current collector.

[0063] 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 disposed on any one or both of the two facing surfaces of the positive electrode current collector.

[0064] 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 and a metal layer formed on at least one surface of the polymer material base. 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 polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.) on a substrate.

[0065] 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.

[0066] 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 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 positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, 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 / 3Mn 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, etc. Examples of lithium-containing phosphates with an olivine structure 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.

[0067] As an example, when the positive electrode plate is used for a sodium ion battery, the positive electrode active material may be a positive electrode active material for a sodium ion battery known in the art. As an 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.

[0068] Examples of the layered transition metal oxides include:

[0069] 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;

[0070] 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;

[0071] 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。

[0072] Examples of the polyanionic compound include:

[0073] A 1 f M 3 g (PO4) i O j X 1 3-j , where A 1 includes 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;

[0074] 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;

[0075] 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;

[0076] 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.

[0077] As an example of the above Prussian blue analogues, for example, the following can be listed:

[0078] 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.

[0079] The battery will be accompanied by the deintercalation and consumption of Li or Na during the charging and discharging process, and the molar content of Li or Na is different when the battery is discharged to different states. In the list of positive electrode materials in this application, the molar content of Li or Na is the initial state of the material, that is, the state before feeding. The positive electrode material is used in the battery system, and the molar content of Li or Na will change after the charge and discharge cycle.

[0080] In the list of positive electrode materials in this application, the molar content of oxygen is only a theoretical value. The release of oxygen from the lattice will cause the molar content of oxygen to change, and the actual molar content of oxygen will fluctuate.

[0081] 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), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, or fluorine-containing acrylate resin.

[0082] 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.

[0083] In some embodiments, the positive electrode sheet can be prepared in the following manner: 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 collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0084] 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.

[0085] 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 disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0086] In some embodiments of the present application, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, copper foil may be used. 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 substrate. 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 material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0087] In some embodiments of the present application, the negative electrode active material may adopt the negative electrode active material for the battery 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, 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.

[0088] 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).

[0089] 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.

[0090] In some embodiments of the present application, the negative electrode active material layer may further optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0091] In some embodiments of the present application, the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (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.

[0092] The present application has no particular limitation on the type of isolation membrane, and any known porous isolation membrane with good chemical stability and mechanical stability can be selected.

[0093] In some embodiments of the present application, the material of the isolation membrane may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene or polyvinylidene fluoride. The isolation membrane may be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0094] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.

[0095] In some embodiments, the secondary battery may include an outer package, which may be used to encapsulate the electrode assembly and the electrolyte.

[0096] In some embodiments, the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the secondary battery may also be a soft package, such as a bag-type soft package. The material of the soft package may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0097] The present application has no particular limitation on the shape of the battery, which may be cylindrical, square or any other shape. For example, Figure 1 The battery cell 1 is a square structure as an example.

[0098] In some embodiments, reference Figure 2 The outer packaging may include a shell 11 and a cover plate 13. Among them, 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.

[0099] 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 according to the application and capacity of the battery module.

[0100] Figure 3 2 is an example of a battery module 2. Figure 3In the battery module 2, the plurality of battery cells 1 may be arranged in sequence along the length direction of the battery module 2. Of course, they may also be arranged in any other manner. Further, the plurality of battery cells 1 may be fixed by fasteners.

[0101] Optionally, the battery module 2 may further include a housing having a receiving space, and the plurality of battery cells 1 are received in the receiving space.

[0102] 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 according to the application and capacity of the battery pack.

[0103] Figure 4 and Figure 5 The battery pack 3 is used as an example. Figure 4 and Figure 5 The battery pack 3 may include a battery box and a plurality of battery modules 2 disposed in the battery box. The battery box includes an upper box body 31 and a lower box body 32. The upper box body 31 can cover the lower box body 32 and form a closed space for accommodating the battery modules 2. The plurality of battery modules 2 can be arranged in the battery box in any manner.

[0104] In addition, the present application also provides an electrical 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 electrical device, and can also be used as an energy storage unit for the electrical device. The electrical 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 are not limited thereto.

[0105] As the electrical device, a secondary battery, a battery module or a battery pack may be selected according to its usage requirements.

[0106] Figure 6 The power consumption device is taken as an example. The power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to meet the high power and high energy density requirements of the power consumption device for the secondary battery, a battery pack or a battery module can be used.

[0107] As another example, the device may be a mobile phone, a tablet computer, a notebook computer, etc. The device is usually required to be light and thin, and a battery may be used as a power source.

[0108] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0109] Example 1

[0110] (1) Preparation of electrolyte

[0111] 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, and 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%.

[0112] (2) Preparation of positive electrode sheet

[0113] Lithium iron phosphate, binder PVDF, and conductive agent acetylene black are added to N-methylpyrrolidone solvent in a mass ratio of 95:3:2, and stirred evenly to obtain positive electrode slurry. The positive electrode slurry is coated on both sides of the current collector aluminum foil, dried, and cold pressed to obtain positive electrode sheets.

[0114] (3) Preparation of negative electrode sheet

[0115] Artificial graphite, conductive carbon black, thickener sodium carboxymethyl cellulose and binder styrene-butadiene rubber are added into deionized water in a mass ratio of 95:1:2:2, stirred evenly to obtain negative electrode slurry, coated on current collector copper foil, dried and cold pressed to obtain negative electrode sheets.

[0116] (4) Isolation film

[0117] A polyethylene film is used as the isolation film.

[0118] (5) Preparation of lithium-ion batteries

[0119] The positive electrode sheet, the separator, and the negative electrode sheet are stacked in order, so that the separator is between the positive and negative electrode sheets to play an isolating role, and then they are 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, forming, and shaping processes, a lithium-ion battery is obtained.

[0120] 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 electrolytes are different, see Table 1 for details, and the other steps are the same as in Example 1 to prepare lithium-ion batteries.

[0121] Table 1

[0122]

[0123]

[0124]

[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 of 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 of the 500th cycle was C3, and the cycle capacity retention rate = C3 / C2*100%.

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

[0130] 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, and left to stand for 5 minutes, which was recorded as the full charge process; then discharged to 2.0V at 1C, which was recorded as the full discharge process, and the discharge capacity after the full discharge process was recorded as C4. Full charge process was performed again to reach 100% soc state. Then the ambient temperature was controlled at 60°C and the battery was stored for 30 days. After 30 days, the ambient temperature was controlled at 25°C, and a full discharge process and a full charge process were performed in sequence, and then the battery was discharged to 2.0V at 1C, left to stand for 5 minutes, and the discharge capacity was recorded as C5. Storage capacity retention rate = C5 / C4*100%.

[0131] (3) Power performance test

[0132] The battery was charged to 3.65V at 1C, then charged to 0.05C at a constant voltage, left to stand for 5 minutes, then discharged at 1C for 0.5h, left to stand for 60min, and the voltage V1 after standing was recorded. Then it was 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 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, and left to stand for 5 minutes, which was recorded as the full charge process; then discharged to 2.0V at 1C, which was recorded as the full discharge process. The full charge process was repeated again to reach 100% soc state, and the volume of the battery was measured and recorded as the volume of the battery before storage. The ambient temperature was then controlled at 60°C and the battery was stored for 30 days. After 30 days, the battery was taken out and placed in a 25°C environment and the volume was measured.

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

[0136] Table 2

[0137]

[0138]

[0139] 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 methane disulfonate, and alkynyl compounds, while the electrolyte additives of Comparative Example 1 only include vinylene carbonate, the electrolyte additives of Comparative Example 2 only include vinylene carbonate and methylene methane disulfonate, the electrolyte additives of Comparative Example 3 only include vinylene carbonate and alkynyl compounds, and the electrolyte additives of Comparative Example 4 only include methylene methane disulfonate and alkynyl compounds. As can be seen from Table 2, the batteries of Examples 1-41 have excellent comprehensive performance compared to Comparative Examples 1-4, wherein 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 DCR, and although the battery of Comparative Example 4 has excellent capacity retention and lower gas production, its DCR is larger. Comparison between Examples 19-24 and Comparative Example 4 shows that the batteries of Examples 19-24 have a higher capacity retention rate; comparison between Examples 25-29 and Comparative Example 3 shows that the batteries of Examples 25-29 have a lower DCR; comparison between Examples 30-33 and Comparative Example 2 shows that the batteries of Examples 30-33 have a higher capacity retention rate and a lower gas production. This shows that the use of the electrolyte additive comprising vinylene carbonate, methylene disulfonate and acetylenic compounds of the present application can simultaneously improve the power performance and cycle performance of the battery, that is, the battery of the present application has excellent comprehensive performance.

[0140] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining 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, and can be optionally 1:0.5-3:0.5-2.

3. The electrolyte additive according to claim 1 or 2, characterized in that: The R includes 4. The electrolyte additive according to any one of claims 1 to 3, characterized in that: The alkynyl compounds include At least one of, optionally, including At least one of .

5. An electrolyte, characterized in that: The electrolyte additive comprises the electrolyte additive described in any one of claims 1 to 4.

6. The electrolyte according to claim 5, characterized in that Based on the total mass of the electrolyte, the weight proportion of the electrolyte additive is 1%-20%, and can be optionally 2%-10%.

7. The electrolyte according to claim 5 or 6, characterized in that Based on the total mass of the electrolyte, the mass proportion of the vinylene carbonate is 0.5%-10%, and can be optionally 1%-5%.

8. The electrolyte according to any one of claims 5 to 7, characterized in that: Based on the total mass of the electrolyte, the weight proportion of the methylene methanedisulfonate is 0.1%-8%, and can be optionally 0.5%-3%.

9. The electrolyte according to any one of claims 5 to 8, characterized in that: Based on the total mass of the electrolyte, the mass proportion of the alkynyl compound is 0.1%-5%, and can be optionally 0.5%-3%.

10. A battery, characterized in that: The invention comprises the electrolyte described in any one of claims 5 to 9.

11. An electrical device, characterized in that: Comprising the battery as claimed in claim 10.

Images