Electrolyte solution, lithium-ion battery and power-consuming device

Abstract

Electrolyte solution comprising an electrolyte salt and an organic solvent, characterized in that the electrolyte salt comprises a lithium salt and the organic solvent comprises a cyclic ester, wherein the mass fraction W1 of the lithium salt in the electrolyte solution and the mass fraction W2 of the cyclic ester in the electrolyte solution 0.2 ≤ W 1 W 2 ≤ 1.06 fulfill.

Description

TECHNICAL AREA

[0001] The present application relates to the technical field of lithium batteries, in particular an electrolyte solution, a lithium-ion battery, a battery module, a battery pack and a power-consuming device. STATE OF THE ART

[0002] In recent years, with the ever-expanding use of lithium-ion batteries, lithium-ion batteries have been used in a variety of fields, such as energy storage systems for hydroelectric, thermal, wind and solar power plants, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment and aerospace.

[0003] However, when the lithium-ion battery is installed in the aforementioned power-consuming devices, the actual operating temperature of the battery is high due to space limitations and the exothermic effect of other parts of the power-consuming device. Therefore, simply improving the battery's cycle and storage performance at room temperature cannot effectively improve its cycle and storage performance in the actual power-consuming device. Consequently, the development and construction of a lithium-ion battery with excellent cycle performance at high temperatures is of great practical value. REVELATION OF THE INVENTION

[0004] The present application is made in consideration of the above subject matter, and its purpose is to provide an electrolyte solution capable of effectively improving the high-temperature storage performance and high-temperature cycle performance of a battery, and to provide a lithium-ion battery, a battery module, a battery pack and a power-consuming device incorporating the electrolyte solution of the present application.

[0005] To achieve the above purpose, a first aspect of the present application comprises an electrolyte solution, wherein the electrolyte solution comprises an electrolyte salt and an organic solvent, wherein the electrolyte salt comprises a lithium salt, and wherein the organic solvent comprises a cyclic ester, the mass fraction W1 of the lithium salt in the electrolyte solution and the mass fraction W2 of the cyclic ester in the electrolyte solution 0.2≤W1W2≤1.06 1.06 fulfilled.

[0006] In each embodiment, in the electrolyte solution of the present application, the range is W1W2 0.5-1.06, optionally 0.8-1.0.

[0007] In each embodiment of the electrolyte solution of the present application, the mass fraction B of the cyclic ester, based on the mass of the organic solvent, is 5%-18%, optionally 13-16%.

[0008] In each embodiment, in the electrolyte solution of the present application, the lithium salt comprises at least one of lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate, comprising that the cyclic ester comprises at least one of ethylene carbonate and propylene carbonate.

[0009] In each embodiment, in the electrolyte solution of the present application, the sum of the molar concentrations of lithium bis(fluorosulfonyl)imide C1 and lithium hexafluorophosphate C2 is optionally 0.86-1.4 M.

[0010] In each embodiment, the electrolyte solution of the present application comprises a film-forming additive, wherein the mass fraction A of the film-forming additive in the electrolyte solution and the mass fraction W2 of the cyclic ester in the electrolyte solution 10≤W25+2*A≤16 fulfill.

[0011] A second aspect of the present application provides a lithium-ion battery comprising an electrolyte solution, a separator, an anode foil, and a cathode foil.

[0012] In each embodiment, the cathode foil comprises an active cathode material LiNi. x Co y Mn z O2, where x+y+z=1, where W2 is the mass fraction of the cyclic ester in the electrolyte solution and x is the nickel atom content, satisfying the following relational equation: 0.5≤W2100x≤0.72.

[0013] In each embodiment, the cathode foil comprises an active cathode material LiNi. x Coy Mn z O2 comprises, where x+y+z=1. With regard to the composition of the electrolyte solution of the present application, the nickel atom content x is 0.5 or more, optionally 0.65, 0.8, 0.96.

[0014] In each embodiment, in the electrolyte solution of the present application, the loading H (with a unit of g) of the anode material on a surface of the collector with an area of ​​1540.25 mm² 2 and the mass fraction W2 of the cyclic ester in the electrolyte solution is given by the following equation: 20≤W2H≤166. Beneficial effects

[0015] By limiting the relative ratios of cyclic esters and lithium salts in the electrolyte solution of lithium-ion batteries, the present application enables the electrolyte solution, which comprises both cyclic esters and lithium salts, to exhibit good conductivity, oxidation resistance, system stability, and a suitable viscosity, and to improve the conductivity of the anode interface film, so that the lithium-ion battery contained therein can exhibit significantly improved storage performance at high temperatures and improved cycle performance at high temperatures, while simultaneously maintaining good power performance. PRESENTATION OF THE REGISTRATION Fig. Figure 1 shows a schematic representation of a lithium-ion battery in an embodiment of the present application; Fig. 2 is a decomposition representation of the in the Fig.1 lithium-ion battery shown in an embodiment of the present application; Fig. Figure 3 shows a schematic representation of a power-consuming device which uses a lithium-ion battery as a power source in an embodiment of the present application. Reference symbol list:

[0016] 5 Lithium-ion battery; 51 Housing; 52 Electrode assembly; 53 Top cover assembly SPECIFIC EXECUTION FORMS

[0017] The following section describes in detail embodiments of the electrolyte solution, the lithium-ion battery, the battery module, the battery pack, and the electrical device of the present application with reference to the accompanying drawings. However, there will be instances where an unnecessarily detailed description is omitted. For example, detailed descriptions of things that are already well known and repeated descriptions of the same structure will be left out. This is to avoid making the following description unnecessarily long and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description serve to ensure a complete understanding of the present application by those skilled in the art and are not intended to limit the subject matter specified in the claims.

[0018] The "range" disclosed here is defined in terms of a lower bound and an upper bound, with a particular range being defined by selecting a lower bound and an upper bound that establish the limits of that range. Ranges defined in this way can include or exclude end values ​​and can be combined in any way; that is, any lower bound can be combined with any upper bound to form a range. For example, if a range of 60-120 and 80-110 is specified for a particular parameter, a range of 60-110 and 80-120 is also to be expected. Furthermore, if the minimum values ​​1 and 2 and the maximum values ​​3, 4, and 5 are specified, the following ranges can be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.Unless otherwise specified, the range "ab" denotes any combination of real numbers between a and b, where both a and b are real numbers. For example, the range "0-5" means that all real numbers between 0 and 5 are listed here, and 0-5 is simply a shorthand representation of the combination of these values. Furthermore, stating that a parameter is an integer ≥ 2 is equivalent to stating that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on.

[0019] Unless expressly stated otherwise, all embodiments and optional embodiments of the present application may be combined to form new technical solutions.

[0020] Unless expressly stated otherwise, all technical features of the present application, as well as optional technical features, may be combined to form a new technical solution.

[0021] Unless expressly stated otherwise, all steps of the present application may be carried out 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) carried out one after the other, or that it may include steps (b) and (a) carried out one after the other. The indication that the method may also include step (c) means, for example, that step (c) may be added to the method in any order; e.g., the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b).

[0022] Unless otherwise stated, references to "including" and "comprehensive" in this application denote an open or closed formulation. For example, the terms "including" and "comprehensive" may mean that other, unlisted components may also be included or contained, or that only the listed components may be included or contained.

[0023] Unless otherwise stated, the term "or" in this application is comprehensive. For example, the phrase "A or B" means "A, B, or both A and B." More precisely, the condition "A or B" is satisfied by any one of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0024] After many years of experience in the production of electrolyte solutions, the inventor of the present application has discovered that, in the electrolyte solution of lithium-ion batteries, the addition of solvents in the form of cyclic esters to the electrolyte solution can significantly improve the dissociation function of the lithium salts, thereby significantly improving the overall conductivity of the electrolyte solution, and that at the same time the composition of the anode interface film is improved, thereby effectively preventing the solvents from undergoing further side reactions on the surface of the anode, which plays an important role in improving the electrochemical performance of the battery.

[0025] However, after numerous experiments, it was found that when using this type of solvent containing cyclic esters in the electrolyte solution, compared to other types of solvents, the cyclic esters can easily accumulate on the cathode surface. Furthermore, these cyclic esters are easily oxidized and decomposed, exacerbating the loss of solvent components from the electrolyte solution and generating a significant amount of gas, ultimately degrading the battery's cycle and storage performance. Secondly, the viscosity of cyclic esters is considerably higher than that of other commonly used solvents, increasing the overall viscosity of the electrolyte solution. This is detrimental to lithium ion transfer and also negatively impacts the battery's electrochemical performance.

[0026] Furthermore, the inventor has observed that in lithium-ion batteries containing internal solvents in the form of cyclic esters, the storage capacity and cycle life of the battery deteriorate significantly at high temperatures compared to room temperature. Following in-depth research and analysis, the inventor suggests the following reasons for this: The high temperature causes the solvents of the cyclic esters to accumulate more rapidly and in larger quantities on the surface of the cathode. Simultaneously, the high temperature accelerates the decomposition of the cyclic esters accumulated on the cathode surface, and the high-temperature environment ultimately leads to a deterioration in the battery's cycle life and storage capacity.

[0027] Building on this, the inventor discovered, after numerous experiments, that by synergistically adjusting the relative concentration of cyclic esters and lithium salts in the electrolyte solution within a specific range, the rate and quantity of such cyclic ester solvent enrichment in the cathode are significantly improved, and the oxidative degradation of the cathode is slowed, provided that the electrolyte solution has high conductivity. Simultaneously, the system viscosity of the electrolyte solution is also significantly improved, which ultimately leads to a substantial increase in the cycle life, storage capacity, and performance of the lithium-ion battery when used with the cyclic ester solvent at high temperatures.

[0028] The formulations of the electrolyte solution in the present application are particularly suitable for ternary lithium-ion batteries with high nickel atom content, even for ternary lithium-ion batteries with ultra-high nickel atom content.

[0029] The formulations of the electrolyte solution in the present application are particularly suitable for improving the cycle performance, storage performance and high-temperature performance of lithium-ion batteries. [Electrolyte solution]

[0030] A first aspect of the present application is an electrolyte solution, wherein the electrolyte solution comprises an electrolyte salt and an organic solvent, wherein the electrolyte salt comprises a lithium salt, and wherein the organic solvent comprises a cyclic ester, the mass fraction W1 of the lithium salt in the electrolyte solution and the mass fraction W2 of the cyclic ester in the electrolyte solution 0.2≤W1W2≤1.06 1.06 fulfilled.

[0031] In the present application, the lithium salt can be at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(trifluorosulfonyl)amide, lithium bis(trifluoromethanesulfonyl)amide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalic acid borate, lithium di(oxalic acid)borate, lithium difluorodioxygenophosphate and lithium tetrafluorooxalic acid phosphate.

[0032] In the present application, the cyclic ester can be selected from more than one of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and vinylethylene carbonate (VEC). At least one of ethylene carbonate and one of propylene carbonate can be selected.

[0033] If more than one type of lithium salt is present in the electrolyte solution, "the mass fraction of the lithium salt in the electrolyte solution" means the mass fraction of the total mass of all types of lithium salt in the electrolyte solution. If more than one type of cyclic ester is present in the electrolyte solution, "the mass fraction of the cyclic ester in the electrolyte solution" means the mass fraction of the total mass of all types of cyclic ester in the electrolyte solution.

[0034] The present application aims to develop an electrolyte solution formulation that exhibits good conductivity, oxidation resistance, system stability, and suitable viscosity, and can improve the conductivity of the anode interface film. After a large number of experiments, it was found that the developed electrolyte solution has an unexpectedly positive effect when the cyclic ester and lithium salt content in the electrolyte solution is adjusted according to a specific relationship. (0.2≤W1W2≤1.06) corresponds, and that the electrolyte solution system has good electrical conductivity, oxidation resistance, system stability and a suitable viscosity, and the conductivity of the anode interface film is improved, the rate and amount of enrichment of the cyclic ester solvent in the anode is improved, the oxidative decomposition of the anode is slowed down and the lithium-ion batteries exhibit good high-temperature cycle performance and good high-temperature storage performance.

[0035] Through extensive research, the inventor discovered that the ratio W1W2 The ratio of lithium salt to cyclic ester in commercially available electrolyte solutions is typically above 1.5 to ensure excellent conductivity in lithium-ion battery electrolyte solutions. However, in practice, this ratio is often too high, resulting in severe oxidative decomposition at the cathode. This significantly impacts battery performance during high-temperature storage, gas generation, and high-temperature cycling. After many years of development, the range of lithium-ion battery electrolyte solutions has been significantly reduced. W1W2 The ratio of lithium salt to solvent of the cyclic ester should not exceed 1.5. After a large number of experiments, the present application develops an electrolyte solution system of 0.2≤W1W2≤1.06, This significantly improves the battery's cycle performance at high temperatures and its storage performance at high temperatures. See especially Table 1.

[0036] In some embodiments, the range is optionally W1W2 In the electrolyte solution of the present application, 0.5 to 1.06, optionally 0.8 to 1.0. See in particular Table 1.

[0037] The further defined area of W1W2 This enables further optimization of the electrolyte solution composition, resulting in a good solvation structure that causes the electrolyte solution to form an inorganic-organic composite interfacial film with better electrical conductivity on the surface of the cathode and anode, giving the battery not only significantly improved storage performance at high temperature and cycle performance at high temperature, but also good current performance.

[0038] Optionally W1W2 selected from a range of values ​​that includes one of the specific point values ​​in Table 1.

[0039] In some embodiments, the mass fraction B of the mass of the cyclic ester in the electrolyte solution of the present application, based on the mass of the organic solvent, is optionally 5% to 18%, optionally 13% to 16%.

[0040] After thorough research, it is found that in electrolyte solutions containing cyclic esters as solvents, the cyclic ester content, relative to the mass of the organic solvent, is generally maintained at more than 20%. This can lead to problems such as significant gas generation during high-temperature storage and poor high-temperature battery cycle performance. In the present application, the cyclic ester content is reduced to between 5% and 18% by sensibly adjusting the specific substance and the electrolyte solution concentration, and the high-temperature storage performance, cycle performance, and energy performance of the battery are significantly improved. Further limiting the value of B to a range of 13% to 16% further enhances the high-temperature cycle performance and storage performance of the lithium-ion battery.See especially Table 2.

[0041] Optional B can be selected from a range of values ​​that includes one of the specific point values ​​in Table 2.

[0042] In some embodiments of the electrolyte solution of the present application, the lithium salt can be selected from at least one of lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate.

[0043] In some embodiments, the ratio is C1C2 the molar concentration C1 of lithium bis(fluorosulfonyl)imide to the molar concentration C2 of lithium hexafluorophosphate 0.05-5, optionally 1-3.5.

[0044] In the present application, due to the limitation of the content of cyclic carbonate, its ability to dissociate lithium salts is somewhat restricted, and the conductivity of the electrolyte solution is affected to some extent.

[0045] Through numerous experimental investigations, the inventors discovered that replacing LiPF6 with lithium bifluorosulfonimide (LiFSI) could improve the conductivity of the electrolyte solution, but LiFSI alone accelerated the corrosion of the aluminum foil. However, the inventors found that the simultaneous use of a mixed salt of LiPF6 and LiFSI, and limiting the ratio of the molar concentration of lithium bis(fluorosulfonimide) C1 to the molar concentration of lithium hexafluorophosphate (LiFSP) C2 to a reasonable range, was not only able to compensate for the loss of electrolyte solution conductivity due to the decrease in the amount of cyclic ester, but also effectively prevented the corrosion of the lithium salt on the aluminum foil, leading to a further improvement in the battery's cycle performance and storage capacity at high temperatures. See Table 3 in particular.

[0046] Optionally C1C2 selected from a range of values ​​that includes one of the specific point values ​​in Table 3.

[0047] In some embodiments, the sum of the molar concentrations of lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate is optionally 0.86-1.4 M, and further optionally 1-1.4 M.

[0048] Furthermore, the total concentration of LiFSI and LiPF6 is limited to a reasonable range because the viscosity of the electrolyte solution becomes too high when the lithium salt concentration is too high. This not only reduces the battery's high-temperature cycle performance and storage capacity but also its overall power output. Conversely, the effective migrated lithium ion content is too low when the total concentration is too low, resulting in poor high-temperature cycle performance and storage capacity. See Table 4 in particular.

[0049] Optionally, the sum of the molar concentrations of lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate can be selected from a range of values ​​that includes one of the specific point values ​​in Table 4.

[0050] In some embodiments, the electrolyte solution of the present application comprises a film-forming additive.

[0051] The mass fraction A of the film-forming additive in the electrolyte solution and the mass fraction W2 of the cyclic ester in the electrolyte solution fulfill 10≤W25+2*A≤16 The film-forming additive may optionally be at least one of fluorinated ethylene carbonate (FEC), vinylene carbonate (VC), vinylene sulfate (DTD) and 1,3-propanesulfonate lactone (PS).

[0052] Cyclic esters are involved in the film formation of the cathode foil and the anode foil during the formation of the lithium-ion battery, but the quality of film formation from cyclic esters alone may be insufficient to maintain good cycle performance of the battery, and combination with film-forming additives can improve the quality of film formation.

[0053] After numerous experiments and statistical analyses, the mass fraction A of the film-forming additive in the electrolyte solution of the present application and the mass fraction W2 of the cyclic ester in the electrolyte solution of the present application satisfy the equation of relationship of the present application. Therefore, the resulting electrolyte solution can not only ensure high-quality film formation on the cathodes and anodes, but also allow the cyclic ester with which it is combined to fully exert its maximum effect (general increase in the conductivity of the electrolyte solution). See in particular Table 5.

[0054] Optionally W25+2*A selected from a range of values ​​that includes one of the specific point values ​​in Table 5, and optionally lies within a range of 11.9-13.5.

[0055] The lithium-ion battery of the present application further comprises a cathode foil, a separator and an anode foil. [Cathode foil]

[0056] The cathode foil comprises a cathode collector and a cathode film layer, which is provided on at least one surface of the cathode collector, the cathode film layer comprising an active cathode material.

[0057] For example, the cathode collector has two surfaces that are opposite each other in its thickness direction, and the cathode film layer is provided on one or both of the two surfaces opposite the cathode collector.

[0058] In some embodiments, the cathode collector can be a metal foil or a composite collector. For example, an aluminum foil can be used as the metal foil. The composite collector can comprise a base layer of polymeric material and a metal layer formed on at least one surface of the polymeric base layer. The composite collector can be formed by depositing metallic material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) onto a polymer substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0059] In some embodiments, the active cathode material may be an active cathode material known in the art for use in batteries. For example, the active cathode material may comprise at least one lithium-containing phosphate with an olivine structure, lithium transition metal oxide, and corresponding modified compounds thereof. However, the present application is not limited to these materials, and other conventional materials suitable for use as active cathode materials in batteries may also be used. It is possible to use only one of these active cathode materials or to use more than two in combination. The layered transition metal oxides include, for example, at least one of the following compounds: lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiNiO2), or lithium cinnamon oxide (e.g., LiNiO2).LiMnO2, LiMn2O4), lithium-nickel-cobalt oxide, lithium-manganese-cobalt oxide, lithium-nickel-manganese oxide, lithium-nickel-cobalt-manganese oxide (e.g. LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 (can be abbreviated), LiNi 0,5 Co 0,2 Mn 0,3 O2 (also known as NCM) 523 (can be abbreviated), LiNi 0,5 Co 0,25 Mn 0,25 O2 (also known as NCM) 211 ), LiNi 0,6 Co 0,2 Mn 0,2 O2 (also known as NCM) 622 (designated), LiNi 0,8 Co 0,1 Mn 0,1 O2 (also known as NCM) 811 designated) and lithium nickel cobalt aluminum oxide (e.g. LiNi 0,85 Co 0,15 Al 0,05O2) and modified compounds thereof, and the like. Examples of lithium-containing phosphates with an olivine structure include lithium iron phosphate (e.g., LiFePO4 (which can also be abbreviated as LFP)), a compound of lithium iron phosphate and carbon; lithium manganese phosphate (e.g., LiMnPO4), a compound of lithium manganese phosphate and carbon; a compound of lithium ferromanganese phosphate; and lithium manganese iron phosphate and carbon.

[0060] In some embodiments, the cathode film layer optionally comprises a binder. For example, the binder may comprise at least one of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0061] In some embodiments, the cathode film layer optionally further comprises a conductive agent. For example, the conductive agent may comprise at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dot, carbon nanotubes, graphene, and carbon nanofibers.

[0062] In some embodiments, the cathode foil can be produced as follows: Dispersing the components described above for the production of the cathode foil, such as the active cathode material, the conductive agent, the binder and any other components, in a solvent (e.g. N-methylpyrrolidone) to form a cathode slurry; applying the cathode slurry to the cathode collector and obtaining the cathode foil after drying, cold pressing and other processes. [Anode foil]

[0063] The anode foil comprises an anode collector and an anode film layer, which is provided on at least one surface of the anode collector, the anode film layer comprising an active anode material.

[0064] For example, the negative electrode collector has two surfaces that are opposite each other in its thickness direction, and the negative electrode film layer is provided on one or both of the two surfaces opposite the negative electrode collector.

[0065] In some embodiments, the anode collector can be a metal foil or a composite collector. For example, a copper foil can be used as the metal foil. The composite collector can comprise a base layer of polymeric material and a metal layer formed on at least one surface of the polymeric base layer. The composite collector can be formed by depositing metallic material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) onto a polymer substrate (such as a substrate made of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0066] In some embodiments, the active anode material may be an active anode material known in the art for use in batteries. The active anode material may, for example, comprise at least one of the following materials: synthetic graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, and lithium titanate. The silicon-based material may be at least one of monolithic silicon, silicon oxides, silicon-carbon complexes, silicon-nitrogen complexes, and silicon alloys. The tin-based material may be at least one of monolithic tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as active anode materials in batteries may also be employed.It is possible that only one of these active anode materials is used, or that more than two are used in combination.

[0067] In some embodiments, the anode film layer optionally comprises a binder. This binder may be at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0068] In some embodiments, the anode film layer optionally further comprises a conductive material. The conductive material can be at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dot, carbon nanotubes, graphene, and carbon nanofibers.

[0069] In some embodiments, the anode film layer optionally includes further additives, such as thickening agents (e.g. sodium carboxymethylcellulose (CMC-Na)), etc.

[0070] In some embodiments, the anode foil can be produced as follows: Dispersing the components described above for the production of the anode foil, such as the active anode material, the conductive agent, the binder and other components, in a solvent (e.g. deionized water) to form an anode slurry; applying the anode slurry to the anode collector and obtaining the anode foil after drying, cold pressing and other processes. [Separator]

[0071] In some embodiments, the lithium-ion battery further comprises a separator. The present application does not impose any specific restrictions regarding the type of separator, and any known separator with a porous structure and good chemical and mechanical stability may be selected.

[0072] In some embodiments, the separator material can be at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film without any particular restriction. If the separator is a multi-layer composite film, the materials of the layers can be the same or different without any particular restriction.

[0073] In some embodiments, the cathode foil, the anode foil and the separator can be assembled into an electrode assembly by a winding process or a stacking process. [Lithium-ion battery]

[0074] The present application further provides a lithium-ion battery comprising an electrolyte solution according to a first aspect of the present application.

[0075] In some embodiments, the lithium-ion battery comprises a cathode foil and an electrolyte solution according to a first aspect of the present application, wherein the cathode foil is an active cathode material LiNi. x Co y Mn z O2 comprises, where x+y+z=1, where the mass fraction W2 of the cyclic ester in the electrolyte solution and where the nickel atom content x satisfies the following relational equation: 0.5≤W2100x≤0.72.

[0076] The electrolyte solution of the present application, combined with a ternary Ni-Co-Mn layered active cathode material for lithium-ion batteries, exhibits significantly improved electrochemical performance, and the amount of cyclic ester in the electrolyte solution is in a reasonable ratio to the nickel content x in the ternary active cathode material. Generally, the activity of the ternary active cathode material is greater the higher the nickel content; however, during battery use, a ternary active cathode material with a high nickel content exacerbates the release of oxygen from the cathode surface, which in turn worsens the oxidative decomposition of the cyclic ester and other solvents.After a large number of experiments, the inventor of the present application found that if the consumption rate of the electrolyte solution of the present application and the nickel atom content x satisfy a certain matching relationship, i.e. 0.5≤W2100x≤0.72, It has the following unexpected technical effects: It can effectively improve the oxygen release problem of the high-nickel battery and effectively slow down the oxidative decomposition of the cyclic ester on the cathode surface, and the corresponding ternary lithium-ion battery has both excellent cycle life and excellent power performance. See especially Table 6.

[0077] In some embodiments, the nickel atom content x may optionally be 0.5 or more, and optionally the nickel atom content may be 0.5, 0.65, 0.8, or 0.96. See in particular Table 8.

[0078] The formulations of the electrolyte solution in the present application are particularly suitable for ternary lithium-ion batteries with high nickel content, even for ternary lithium-ion batteries with ultra-high nickel content, so that good storage performance at high temperature, good cycle performance at high temperature and good performance are ensured simultaneously.

[0079] In some embodiments in the electrolyte solution of the present application, the loading H (with a unit of g) of the anode material on a surface of the collector with an area of ​​1540.25 mm² satisfies 2 and the mass fraction W2 of the cyclic ester in the electrolyte solution is given by the following equation: 20≤W2H≤166, 166, optional 50≤W2H≤141. 141.

[0080] After a large number of experiments, the inventors of the present application found that if the amount of cyclic ester in the electrolyte solution of the present application has a synergistic effect with the H loading of the anode material, and if the two satisfy a certain matching relationship, i.e. 20≤W2H≤166, 166, it will play a significant role in improving the electrochemical performance of the lithium-ion battery as a whole. See especially Table 7.

[0081] In some embodiments, the lithium-ion battery of the present application is a shell battery.

[0082] In some embodiments, the lithium-ion battery may include an outer packaging. The outer packaging can be used to encapsulate the electrode assembly and electrolyte described above.

[0083] In some embodiments, the outer packaging of the lithium-ion battery can be a hard casing, such as a hard plastic casing, an aluminum casing, a steel casing, etc. The outer packaging of the lithium-ion battery can also be a soft casing, such as a bag-like soft casing. The soft casing can be made of plastic, and examples of such plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0084] The present application does not impose any specific restrictions regarding the shape of the lithium-ion battery, which may be cylindrical, square, or any other shape. For example, in Fig. Figure 1 shows an example of a lithium-ion battery 5 with a rectangular structure.

[0085] In some embodiments, such as in Fig.As shown in Figure 2, the outer packaging can comprise a housing 51 and a cover plate 53. The housing 51 can comprise a base plate and side plates connected to the base plate, the base plate and the side plates forming a receiving cavity. The housing 51 has an opening that communicates with the receiving cavity, and the cover plate 53 can serve to cover the opening to close the receiving cavity. The cathode foil, the anode foil, and the separator can be assembled into an electrode assembly 52 by a winding or stacking process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte solution is exchanged into the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the lithium-ion battery 5 can be one or more, and the person skilled in the art can make the selection as required.

[0086] Fig.Figure 3 shows an example of a power-consuming device. The device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc. Example of implementation

[0087] The following describes exemplary embodiments of the present application. The embodiments described below are exemplary, serve to explain the present application, and cannot be construed as limiting the present application. Unless specific techniques or conditions are indicated in the exemplary embodiments, they correspond to the techniques or conditions described in the relevant literature or to the information in the product specification. The reagents or instruments used without manufacturer information are all commercially available products. Unless otherwise stated, the concentrations of the components in the exemplary embodiments of the present application are measured by mass, excluding crystallized water.

[0088] The following descriptive terms: “Electrolyte solution of embodiment 1-1” means the electrolyte solution used in the manufacturing process of the lithium-ion battery of embodiment 1-1; “Cathode foil of embodiment 1-1” means the cathode foil used in the manufacturing process of the lithium-ion battery of embodiment 1-1; “Anode foil of embodiment 1-1” means the anode foil used in the manufacturing process for the lithium-ion battery of embodiment 1-1; “Separator of embodiment 1-1” means the separator used in the manufacturing process of the lithium-ion battery of embodiment 1-1; “Lithium-ion battery of embodiment 1-1” means a lithium-ion battery made from the cathode foil, the separator, the anode foil, and the electrolyte solution of embodiment 1-1.

[0089] The raw materials used in the embodiments of the present application are the following: Ternary nickel-cobalt-manganese material (LiMO2, M is a Ni-Co-Mn solid solution, the specific ratio of which is given in the respective embodiments) Artificial Graphite (Guangdong Kaijin New Energy Technology Co., Ltd.) N-Methylpyrrolidone (NMP, CAS: 872-50-4, Shanghai McLean Biotechnology Co., Ltd.) Polyvinylidene fluoride (CAS: 24937-79-9, Shanghai Macklin Biochemical Co.,Ltd.) Acetylene black (Guangdong Kaijin New Energy Technology Co., Ltd.) Conductive carbon black (Guangdong Kaijin New Energy Technology Co., Ltd.) Acrylate (CAS: 25067-02-1, Shanghai Macklin Biochemical Co.,Ltd.) Ethylene carbonate (EC, CAS: 96-49-1, Shanghai Macklin Biochemical Co.,Ltd.) Dimethyl carbonate (DMC, CAS: 616-38-6, Shanghai Macklin Biochemical Co.,Ltd.) Methyl ethyl carbonate (EMC, CAS: 623-53-0, Shanghai Macklin Biochemical Co.,Ltd.) Lithium hexafluorophosphate (LiPF6, CAS: 21324-40-3, Guangzhou Tinci Materials Technology Co.,Ltd) Lithium bis(fluorosulfonyl)imide (LiFSI, CAS: 171611-11-3, Guangzhou Tinci Materials Technology Co.,Ltd) Fluorinated Ethylene Carbonate (FEC, CAS: 114435-02-8, Guangzhou Tinci Materials Technology Co.,Ltd.) Example 1-1 [Preparation of the electrolyte solution]

[0090] In a glove box with an argon atmosphere and a water content of <10 ppm, 32.64 g EC, 60.84 g EMC, 6.25 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. [Production of the cathode foil]

[0091] The active cathode material is made of ternary nickel-cobalt-manganese material (LiNi). 0,8 Co 0,1 Mn 0,1O2), the binder of polyvinylidene fluoride and the conducting agent of acetylene black were mixed in a mass ratio of 8:1:1, and the solvent NMP was added to obtain the cathode slurry under the action of a vacuum mixer; the cathode slurry was applied uniformly to the aluminum foil of the cathode collector with a thickness of 13 µm in a quantity of 0.28 g (dry weight) / 1540.25 mm². 2 applied; The aluminum foil was dried at room temperature and then placed in an oven at 120 °C for 1 hour, then cold-pressed and cut to obtain the cathode foil. [Production of the anode foil]

[0092] Artificial graphite, conductive carbon black, and binder acrylate were mixed in a mass ratio of 92:2:6, deionized water was added, and an anode slurry was prepared using a vacuum mixer; the anode slurry was applied evenly to the 8 µm thick copper foil of the anode collector in a quantity of 0.18 g (dry weight) / 1540.25 mm². 2 applied; The copper foil was dried at room temperature and then placed in an oven at 120 °C for 1 hour to dry, then cold-pressed and cut to obtain the anode foil. [Separator]

[0093] The separator was purchased from Cellgard, model cellgard2400. [Manufacturing of the lithium-ion battery]

[0094] The cathode foil, separator, and anode foil were stacked sequentially, with the separator sandwiched between the cathode foil and anode foil to ensure insulation, and then wound to form a bare electrical core. The bare electrical core, with a capacity of 4.3 Ah, was placed in the outer packaging film, and 8.6 g of the electrolyte solution described above was injected into the dried battery. The lithium-ion battery was then obtained after vacuum encapsulation, settling, forming, shaping, and other processes. Example 1-2

[0095] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 18.17 g EC, 72.68 g EMC, 9 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 1-3

[0096] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 10.10 g EC, 81.74 g EMC, 8 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Exemplary embodiment 1-4

[0097] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 12.83 g EC, 75.648 g EMC, 11.38 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 1-5

[0098] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 12.67 g EC, 74.68 g EMC, 12.5 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 1-6

[0099] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 9.86 g EC, 79.74 g EMC, 10.25 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Comparative example 1

[0100] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 82.98 g EC, 4.37 g EMC, 12.5 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Comparative example 2

[0101] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 10.44 g EC, 78.03 g EMC, 11.38 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 2-1

[0102] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 2.93 g PC, 94.67 g EMC, 2.25 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 2-2

[0103] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 4.80 g PC, 91.29 g EMC, 3.75 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 2-3

[0104] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 7.51 g PC, 86.34 g EMC, 6 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 2-4

[0105] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 9.25 g PC, 83.22 g EMC, 7.38 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 2-5

[0106] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 11.76 g PC, 78.71 g EMC, 9.38 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 2-6

[0107] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 13.38 g PC, 75.84 g EMC, 10.63 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 2-7

[0108] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 15.72 g PC, 71.62 g EMC, 12.5 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 2-8

[0109] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 17.22 g PC, 68.88 g EMC, 13.75 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte for this embodiment was completely stirred and dissolved. Example 3-1

[0110] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 13.92 g EC, 73.55 g EMC, 12.38 g LiPF6 and 0.15 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 3-2

[0111] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 14.04 g EC, 73.32 g EMC, 11.90 g LiPF6 and 0.73 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 3-3

[0112] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 15.5 g EC, 70.55 g EMC, 6.25 g LiPF6 and 7.7 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 3-4

[0113] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 15.82 g EC, 69.94 g EMC, 5 g LiPF6 and 9.24 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 3-5

[0114] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 16.04 g EC, 69.53 g EMC, 4.17 g LiPF6 and 10.27 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 3-6

[0115] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 16.39 g EC, 68.85 g EMC, 2.78 g LiPF6 and 11.98 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 3-7

[0116] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 16.57 g EC, 68.51 g EMC, 2.08 g LiPF6 and 12.83 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 3-8

[0117] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 16.62 g EC, 68.43 g EMC, 1.92 g LiPF6 and 13.03 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 4-1

[0118] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 10.85 g EC, 79.39 g EMC, 4.38 g LiPF6 and 5.39 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 4-2

[0119] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 13.18 g EC, 74.97 g EMC, 5.31 g LiPF6 and 6.55 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 4-3

[0120] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 15.5 g EC, 70.55 g EMC, 6.25 g LiPF6 and 7.70 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 4-4

[0121] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 21.7 g EC, 58.77 g EMC, 8.75 g LiPF6 and 10.78 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 4-5

[0122] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 22.48 g EC, 57.3 g EMC, 9.06 g LiPF6 and 11.17 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 5-1

[0123] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 12.30 g EC, 72.55 g EMC, 11.44 g LiPF6, 0.15 g LiFSI and 3.55 g FEC were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 5-2

[0124] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 10.35 g EC, 75.87 g EMC, 9.63 g LiPF6, 0.15 g LiFSI and 4 g FEC were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 5-3

[0125] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 12.51 g EC, 70.89 g EMC, 11.75 g LiPF6, 0.15 g LiFSI and 4.7 g FEC were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 5-4

[0126] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 10.76 g EC, 73.31 g EMC, 10.13 g LiPF6, 0.15 g LiFSI and 5.65 g FEC were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 5-5

[0127] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 11.03 g EC, 71.29 g EMC, 10.63 g LiPF6, 0.15 g LiFSI and 6.9 g FEC were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 5-6

[0128] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the electrolyte solution was prepared in the following steps: In a glove box with an argon atmosphere and a water content of <10 ppm, 13.55 g EC, 66.17 g EMC, 13.13 g LiPF6, 0.15 g LiFSI and 7 g FEC were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 6-1

[0129] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the ternary material of the active cathode material used in this embodiment is LiNi. 0,99 Co 0,005 Mn 0,005O2 is present. Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 46.286 g EC, 39.43 g EMC, 4.13 g LiPF6 and 10.16 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 6-2

[0130] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the ternary material of the active cathode material used in this embodiment is LiNi. 0,69 Co 0,16 Mn 0,15 O2 is.

[0131] Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 34.28 g EC, 51.43 g EMC, 4.13 g LiPF6 and 10.16 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 6-3

[0132] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the ternary material of the active cathode material used in this embodiment is LiNi. 0,47 Co 0,15 Mn 0,38 O2 is.

[0133] Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 27.86 g EC, 57.85 g EMC, 4.13 g LiPF6 and 10.16 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 6-4

[0134] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the ternary material of the active cathode material used in this embodiment is LiNi. 0,32 Co 0,19 Mn 0,57 O2 is.

[0135] Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 23.14 g EC, 62.57 g EMC, 4.13 g LiPF6 and 10.16 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 6-5

[0136] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the ternary material of the active cathode material used in this embodiment is LiNi. 0,25 Co 0,18 Mn 0,57O2 is present. Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 20.06 g EC, 65.65 g EMC, 4.13 g LiPF6 and 10.16 g LiFSI were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Exemplary embodiment 7-1

[0137] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the anode coating quantity in this embodiment is 1.698 mg / 1540.25 mm². 2Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 30.57 g EC, 63.31 g EMC, 6.11 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Exemplary embodiment 7-2

[0138] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the anode coating quantity in this embodiment is 0.873 mg / 1540.25 mm². 2 Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 17.47 g EC, 73.80 g EMC, 8.73 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Exemplary embodiment 7-3

[0139] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the anode coating quantity in this embodiment is 0.192 mg / 1540.25 mm². 2 Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 9.61 g EC, 82.71 g EMC, 7.69 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 7-4

[0140] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the anode coating quantity in this embodiment is 0.158 mg / 1540.25 mm². 2Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 12.67 g EC, 75.94 g EMC, 11.4 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 7-5

[0141] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the anode coating quantity in this embodiment is 0.115 mg / 1540.25 mm². 2 Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 12.67 g EC, 74.67 g EMC, 12.67 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 7-6

[0142] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the anode coating quantity in this embodiment is 0.09 mg / 1540.25 mm². 2 Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 12.67 g EC, 74.67 g EMC, 12.67 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Exemplary embodiment 7-7

[0143] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the anode coating quantity in this embodiment is 0.079 mg / 1540.25 mm². Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 12.67 g EC, 74.67 g EMC, and 12.67 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by thorough stirring and dissolution. Example 7-8

[0144] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the anode coating quantity in this embodiment is 0.058 mg / 1540.25 mm². 2Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 9.61 g EC, 80.3 g EMC, 10.09 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 8-1

[0145] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the ternary material of the active cathode material used in this embodiment is LiNi. 0,5 Co 0,2 Mn 0,3 O2 is.

[0146] Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 16 g EC, 69.6 g EMC, 14.4 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 8-2

[0147] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the ternary material of the active cathode material used in this embodiment is LiNi. 0,65 Co 0,05 Mn 0,3 O2 is.

[0148] Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 16 g EC, 69.6 g EMC, 14.4 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 8-3

[0149] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the ternary material of the active cathode material used in this embodiment is LiNi. 0,85 Co 0,05 Mn 0,1 O2 is.

[0150] Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 16 g EC, 69.6 g EMC, 14.4 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. Example 8-4

[0151] The manufacturing process of the lithium-ion battery corresponds in its entirety to embodiment 1-1, with the difference that the ternary material of the active cathode material used in this embodiment is LiNi. 0,96 Co 0,02 Mn 0,02 O2 is.

[0152] Furthermore, the step of preparing the electrolyte solution is as follows: In a glove box with an argon atmosphere and a water content of <10 ppm, 16 g EC, 69.6 g EMC, 14.4 g LiPF6 were placed in a beaker, and the electrolyte solution for this embodiment was obtained by sufficient stirring and dissolving. [Relevant parameters and battery performance test] 1. DCR (Direct Current Resistance) test during the first discharge

[0153] At 25 °C, the lithium-ion batteries of the above-mentioned embodiments and comparative embodiments are each charged to 4.25V at a charge rate of 1C, then charged at a constant voltage until a current of less than 0.05C is reached, and subsequently discharged at a discharge rate of 1C for 30 minutes, with the battery's state of charge (SOC) at 50% and the voltage recorded as V1; then the batteries are discharged at a discharge rate of 4C (the corresponding current at 4C is I) for 30 seconds, with the voltage recorded as V2, so the initial discharge DCR of the lithium-ion battery = (V1-V2) / I, the specific values ​​are shown in Tables 1-8. 2. Cycle performance test at 60°C

[0154] The battery was charged at 60°C with a constant current of 1C to 4.25V, then charged with a constant voltage of 4.25V to a current of 0.05C, left to stand for 5 minutes, and then discharged with a constant current of 1C to 2.5V; the resulting capacity is recorded as the initial capacity C0. The above steps are repeated for the same battery, and the counting starts at the same time; the discharge capacity C 300 The battery was recorded after the 300th cycle; the battery's capacity retention rate after 300 cycles is P=C. 300 / C0*100 %.

[0155] The lithium-ion battery of the embodiments and the comparative examples is tested according to the procedure described above, and the specific values ​​are listed in Tables 1-8. 3. Storage performance test at 60 °C

[0156] At 25 °C, the battery was charged to 4.25V with a constant current of 0.5C, then charged to a current of 0.05C with a constant voltage of 4.25V, left to stand for 5 minutes, and then discharged to 2.5V with a constant current of 0.5C, with the discharged capacity being recorded as the initial capacity C0.

[0157] The aforementioned battery was further charged at a constant current of 0.5C to 4.25V and then discharged at a constant current of 0.05C at 4.25V. The battery was then placed in a thermostat at 60°C and stored for 60 days before being removed. The removed battery was placed at an ambient temperature of 25°C until the temperature of the lithium-ion battery had completely cooled to 25°C. The lithium-ion battery was then discharged at a constant current of 0.5C to 2.5V, then charged at a constant current of 0.5C to 4.25V, and finally discharged at a constant current of 0.5V to 2.5V. The discharge capacity at this point is C1. Therefore, the battery's capacity retention rate at high temperature after 60 days of storage is M = C1 / C0 × 100%.

[0158] The lithium-ion battery of the other embodiments and the comparative examples is tested according to the procedure described above, and the specific values ​​are listed in Tables 1-8.

[0159] Table 1: Effect of the relative ratio of lithium salt and cyclic ester on battery performance number Relevant parameters of the electrolyte solution Battery power lithium salt Cyclic ester W1(%) W2(%) W1W2 W1 B(%) Capacity maintenance rate for cycles at 60 °CP (%) Capacity retention rate for storage at 60 °CM (%) Initial DCR(mΩ) Example 1-1 LiFSI+LiPF6 EC 6,40 32,68 0,2 35 75,6 81,2 20,5 Example 1-2 LiFSI+LiPF6 EC 9,15 18,17 0,5 20 79,1 84,1 19,9 Execution- LiFSI+LiPF6 EC 8,15 10,10 0,81 11 84,3 88,7 18,8 examples 1-3 Exemplary embodiment 1-4 LiFSI+LiPF6 EC 11,53 12,83 0,9 14,5 86,1 90,1 16,5 Example 1-5 LiFSI+LiPF6 EC 12,65 12,67 1,0 14,5 82,1 87,3 17,1 Example 1-6 LiFSI+LiPF6 EC 10,4 9,86 1,06 11 79,9 83,3 17,4 Comparative example 1 LiFSI+LiPF6 EC 12,65 82,98 0,15 95 71,5 76,5 27,5 Comparative example 2 LiFSI+LiPF6 EC 11,53 10,44 1,1 11,8 72,8 77,8 23,4 Remarks W1: Mass fraction of the lithium salt in the electrolyte solution; W2: Mass fraction of the cyclic ester in the electrolyte solution; B: Mass fraction of the cyclic ester in the organic solvent.

[0160] Table 2: Effect of the cyclic ester content in organic solvent on battery performance number Relevant parameters of the electrolyte solution Battery power lithium salt Cyclic ester W1(%) W2(%) W1W2 B(%) Capacity maintenance rate for cycles at 60 °C (%) Capacity retention rate for storage at 60 °C (%) Initial DCR(mΩ) Example 2-1 LiFSI+LiPF6 PC 2,4 2,93 0,82 3 74,7 79,1 18,1 Example 2-2 LiFSI+LiPF6 PC 3,9 4,8 0,81 5 75,8 81,1 17,2 Example 2-3 LiFSI+LiPF6 PC 6,15 7,51 0,82 8 79,8 82,6 16,5 Example 2-4 LiFSI+LiPF6 PC 7,53 9,25 0,81 10 81,8 83,7 16,1 Example 2-5 LiFSI+LiPF6 PC 9,53 11,76 0,81 13 84,1 87,1 15,1 Example 2-6 LiFSI+LiPF6 PC 10,78 13,38 0,81 15 82,9 85,1 14,3 Example 2-7 LiFSI+LiPF6 PC 12,65 15,72 0,8 18 80,7 82,1 15,7 Example 2-8 LiFSI+LiPF6 PC 13,9 17,22 0,81 20 73,9 78,9 20,1

[0161] Table 3: Effect of the relative content of the different lithium salts on battery performance number Relevant parameters of the electrolyte solution Battery power lithium salt Cyclic ester W1W2 C1C2 C1 [C1+ C2](M) Capacity maintenance rate for cycles at 60°C (%) Capacity retention rate for storage at 60 °C (%) Initial DCR (mΩ) Example 3-1 LiFSI+LiPF6 EC 0,9 0,01 1 76,8 80,3 17,1 Example 3-2 LiFSI+LiPF6 EC 0,9 0,05 1 78,5 81,4 16,9 Example 3-3 LiFSI+LiPF6 EC 0,9 1 1 83,1 82,7 16,3 Example 3-4 LiFSI+LiPF6 EC 0,9 1,5 1 84,1 84,1 15,9 Example 3-5 LiFSI+LiPF6 EC 0,9 2 1 85,4 88,2 15,6 Example 3-6 LiFSI+LiPF6 EC 0,9 3,5 1 83,2 86,4 16,4 Example 3-7 LiFSI+LiPF6 EC 0,9 5 1 80,1 84,1 16,9 Example 3-8 LiFSI+LiPF6 EC 0,9 5,5 1 75,8 81,0 17,2 Remarks C1: the molar concentration of lithium bis(fluorosulfonyl)imide; C2: the molar concentration of lithium hexafluorophosphate

[0162] Table 4: Effect of the total lithium salt concentration on battery performance number Relevant parameters of the electrolyte solution Battery power lithium salt Cyclic ester W1W2 W1 C1C2 [C1+C2](M) Capacity maintenance rate for cycles at 60 °C (%) Capacity retention rate for storage at 60 °C (%) Initial DCR(mΩ) Example 4-1 LiFSI+LiPF6 EC 0,9 1 0,7 77,8 79,9 17,9 Example 4-2 LiFSI+LiPF6 EC 0,9 1 0,86 81,5 82,3 17,0 Example 4-3 LiFSI+LiPF6 EC 0,9 1 1 83,1 82,7 16,3 Example 4-4 LiFSI+LiPF6 EC 0,9 1 1,4 82,1 83,1 15,9 Example 4-5 LiFSI+LiPF6 EC 0,9 1 1,46 78,1 80,1 17,2

[0163] Table 5: Impact of [W25+2*A] on battery performance number Relevant parameters of the electrolyte solution Battery power Lithiu m-salt Cyclic ester A (%) W2 (%) W1W2 Form image additive W2H Capacity maintenance rate for cycles at 60 °C (%) Capacity retention rate for storage at 60 °C (%) Initial DCR(mΩ) Example 5-1 LiFSI+LiPF6 EC 3,55 12,30 0,94 FEC 9,56 82,1 83,4 17,4 Example 5-2 LiFSI+LiPF6 EC 4 10,35 0,95 FEC 10,07 83,1 84,3 16,5 Example 5-3 LiFSI+LiPF6 EC 4,7 12,51 0,95 FEC 11,90 84,1 85,3 16,1 Example 5-4 LiFSI+LiPF6 EC 5,65 10,76 0,96 FEC 13,45 85,3 86,5 15,5 Example 5-5 LiFSI+LiPF6 EC 6,9 11,03 0,98 FEC 16,00 84,6 84,3 16,5 Example 5-6 LiFSI+LiPF6 EC 7 13,55 0,98 FEC 16,71 82 82,4 17,3 Remarks A: Mass fraction of the film-forming additive in the electrolyte solution;

[0164] Table 6: Effect of other battery parameters on battery performance number Relevant battery performance Battery power lithium salt Cyclic ester 100x W2(%) W1W2 W1 W2100x Capacity maintenance rate for cycles at 60 °C (%) Capacity retention rate for storage at 60 °C (%) Initial DCR(mΩ) Example 6-1 LiFSI+LiPF6 EC 99 46,28 0,31 0,47 80,8 81,5 17,1 Example 6-2 LiFSI+LiPF6 EC 69 34,28 0,42 0,5 81,3 82,0 16,9 Example 6-3 LiFSI+LiPF6 EC 47 27,86 0,51 0,59 85,4 86,7 15,7 Example 6-4 LiFSI+LiPF6 EC 32 23,14 0,62 0,72 84,1 85,2 16,5 Example 6-5 LiFSI+LiPF6 EC 25 20,06 0,71 0,8 81,1 81,8 18,1

[0165] Table 7: Effect of other battery parameters on battery performance number Relevant battery parameters Battery power lithium salt Cyclic ester W2 (%) H(g) W1W2 W1 W2H Capacity maintenance rate for cycles at 60 °C (%) Capacity retention rate for storage at 60 °C (%) Initial DCR(mΩ) Exemplary embodiment 7-1 LiPF6 EC 30,57 1,698 0,2 18,00 79,1 80,5 17,2 Exemplary embodiment 7-2 LiPF6 EC 17,47 0,873 0,5 20,00 81,5 81,3 16,9 Exemplary embodiment 7-3 LiPF6 EC 9,61 0,192 0,8 50,05 83,1 82,3 16,5 Example 7-4 LiPF6 EC 12,67 0,158 0,9 80,19 84,1 84,2 16,2 Example 7-5 LiPF6 EC 12,67 0,115 1,0 110,17 85,1 86,4 16 Example 7-6 LiPF6 EC 12,67 0,09 1,0 140,78 83,2 85,1 16,4 Exemplary embodiment 7-7 LiPF6 EC 12,67 0,079 1,0 160,38 82,1 84,2 16,5 Example 7-8 LiPF6 EC 9,61 0,058 0,95 165,69 81,1 81,3 16,5 Remarks H is the loading of the anode material on a surface of the collector with an area of ​​1540.25 mm² 2

[0166] Table 8: Effect of other battery parameters on battery performance number Relevant battery parameters Battery power lithium salt Cyclic ester 100x W2(%) W1W2 W1 W2100x Capacity maintenance rate for cycles at 60 °C (%) Capacity retention rate for storage at 60 °C (%) Initial DCR(mΩ) Example 8-1 LiPF6 EC 50 16,0 0,9 0,32 85,4 86,7 15,7 Example 8-2 LiPF6 EC 65 16,0 0,9 0,25 83,1 84,0 16,9 Example 8-3 LiPF6 EC 85 16,0 0,9 0,19 80,2 80,4 18,1 Example 8-4 LiPF6 EC 96 16,0 0,9 0,17 78,4 77,6 22,6 Remarks W1: Mass fraction of the lithium salt in the electrolyte solution; W2: Mass fraction of the cyclic ester in the electrolyte solution; x is the content of nickel atoms in the material LiNi X Co y MnzO2.

[0167] Table 1 shows that the capacity retention rate during high-temperature cycles and the capacity retention rate for high-temperature storage of the lithium-ion battery corresponding to all the above embodiments is significantly higher than that of the corresponding comparative examples 1-2. At the same time, the initial discharge DCR of all embodiments is lower than that of the corresponding comparative examples 1-2.

[0168] In a comprehensive comparison of embodiments 1-1 to 1-6, if 0.2≤W1W2≤1.06, The capacity retention rate during high-temperature cycles of the lithium-ion battery is higher than 75%, the capacity retention rate for high-temperature storage devices is higher than 80%, and the initial discharge DCRs are also all within 20.5 mΩ. 0.8≤W1W2≤1.0 This will further improve the capacity retention rate in high-temperature cycles, the capacity retention rate in high-temperature storage systems, and the initial discharge DCR of the lithium-ion battery.

[0169] In a comprehensive comparison of embodiments 2-1 to 2-8, when the value of W1W2 If the value of B is constant, and the value is in the range of 5%–18%, the lithium-ion battery will have a high-temperature cycle capacity retention rate greater than 75%, a high-temperature storage capacity retention rate greater than 80%, and an initial discharge DCR not exceeding 17.2 mΩ. If the value of B is in the range of 13%–16%, the high-temperature cycle capacity retention rate, the high-temperature storage capacity retention rate, and the initial discharge DCR of the lithium-ion battery will be further improved. In a comprehensive comparison of embodiments 3-1 to 3-8, when the value of W1W2 and C1+C2 is a constant value when the value of C1C2 If the value is in the range of 0.05-5, the lithium-ion battery has a high-temperature cycle capacity retention rate higher than 78.5%, a high-temperature storage capacity retention rate higher than 81%, and an initial discharge DCR not exceeding 17 mΩ. If the value of C1C2 If the value is in the range of 1 to 3.5, the capacity retention rate in high-temperature cycles, the capacity retention rate in high-temperature storage and the initial discharge DCR of the lithium-ion battery will be further improved. In a comprehensive comparison of embodiments 4-1 to 4-5, when the value of W1W2 and C1C2 If the value of (C1+C2) is constant and in the range of 0.86–1.4 MΩ, the lithium-ion battery will have a high-temperature cycle capacity retention rate that is all higher than 81.5%, a high-temperature storage capacity retention rate that is all higher than 82.3%, and an initial discharge DCR that is no more than 17 mΩ. If the value of (C1+C2) is in the range of 1–1.4 MΩ, the high-temperature cycle capacity retention rate, the high-temperature storage capacity retention rate, and the initial discharge DCR of the lithium-ion battery will be further improved.

[0170] In a comprehensive comparison of embodiments 5-1 to 5-6, when the value of W1W2 a constant value is when the value of [W25+2*A] If the value is in the range of 10-16, the lithium-ion battery has a high-temperature cycle capacity retention rate higher than 83%, a high-temperature storage capacity retention rate higher than 84%, and an initial discharge DCR not exceeding 16.5 mΩ. If the value of [W25+2*A] With values ​​in the range of 11.9 to 13.5, the capacity retention rate in high-temperature cycles, the capacity retention rate in high-temperature storage systems, and the initial discharge DCR of the lithium-ion battery will be further improved.

[0171] In a comprehensive comparison of embodiments 6-1 to 6-5, when the value of W2100x If the coefficient of performance (CDP) is in the range of 0.5-0.72, the lithium-ion battery has a high-temperature cycle capacity retention rate higher than 81.3%, a high-temperature storage capacity retention rate higher than 82%, and an initial discharge DCR not exceeding 17 mΩ. In a comprehensive comparison of embodiments 7-1 to 7-8, when the value of W1W2 A constant value is one where the value of is within the range of W2H If the value is 20-166, the lithium-ion battery has a high-temperature cycle capacity retention rate that is all higher than 81.5%, a high-temperature storage capacity retention rate that is all higher than 81.3%, and an initial discharge DCR that is no more than 16.9 mΩ. If the value of W2H Within the range of 50-141, the capacity retention rate in high-temperature cycles, the capacity retention rate in high-temperature storage, and the initial discharge DCR of the lithium-ion battery are further improved.

[0172] Exemplary embodiments 8-1 to 8-4 show that for various types of ternary active cathode materials made of LiNi x Co y Mn z O2, which are commonly used in current ternary active cathode materials, i.e. ternary active cathode materials with a nickel atom content of 0.5, 0.65, 0.85 or 0.96 respectively, which give the corresponding lithium-ion batteries a good capacity retention rate in high-temperature cycles and a capacity retention rate in high-temperature storage and initial discharge DCR.

[0173] It should be noted that the present application is not limited to the embodiments mentioned above. The embodiments mentioned above are only examples, and embodiments within the scope of the technical solution of the present application that have essentially the same composition as the technical idea and have the same effect are included in the technical scope of the present application. Furthermore, within the scope of the present application, other possibilities for constructing the embodiments by combining some of the constituent elements of the embodiments and applying various deformations to the embodiments that a person skilled in the art can imagine without departing from the subject matter of the present application are also included.

Claims

[1] Electrolyte solution comprising an electrolyte salt and an organic solvent, characterized by , that the electrolyte salt comprises a lithium salt and the organic solvent comprises a cyclic ester, wherein the mass fraction W1 of the lithium salt in the electrolyte solution and the mass fraction W2 of the cyclic ester in the electrolyte solution 0.2≤W1W2≤1.06 fulfill. [2] Electrolyte solution according to claim 1, characterized by , that the area of W1W2 0.5-1.06, optionally 0.8-1.

0. [3] Electrolyte solution according to claim 1 or 2, characterized by , that the mass fraction B of the cyclic ester relative to the mass of the organic solvent is 5%-18%, optionally 13-16%. [4] Electrolyte solution according to any one of claims 1 to 3, characterized by, that the electrolyte salt comprises at least one of lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate and the cyclic ester comprises at least one of ethylene carbonate and propylene carbonate. [5] Electrolyte solution according to claim 4, characterized by that the relationship C1C2 The molar concentration C1 of lithium bis(fluorosulfonyl)imide to the molar concentration C2 of lithium hexafluorophosphate is 0.05-5, optionally 1-3.5; wherein the sum of the molar concentrations of lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate (C1+C2) is optionally 0.86-1.4 M. [6] Electrolyte solution according to any one of claims 1 to 5, characterized by , that it comprises a film-forming additive, wherein the mass fraction A of the film-forming additive in the electrolyte solution and the mass fraction W2 of the cyclic ester in the electrolyte solution 10≤W25+2*A≤16 fulfill. [7] Lithium-ion battery, characterized bythat it comprises a cathode foil, an anode foil and an electrolyte solution according to any one of claims 1 to 6. [8] Lithium-ion battery according to claim 7, characterized by , that the cathode foil comprises an active cathode material LiNixCoyMnzO2, where x+y+z=1, where the mass fraction W2 of the cyclic ester in the electrolyte solution and the nickel atom content x satisfy the following relation equation: 0.5≤W2100x≤0.

72. [9] Lithium-ion battery according to claim 8, characterized by that the nickel atom content is x 0.5 or more, optionally 0.65, 0.8, 0.

96. [10] Lithium-ion battery according to any one of claims 7 to 9, characterized by , that the loading H (with a unit of g) of the anode material on a surface of the collector with an area of ​​1540.25 mm² 2 and the mass fraction W2 of the cyclic ester in the electrolyte solution satisfies the following relational equation: 20≤W2H≤166. [11] Power-consuming device, characterized by that it comprises a lithium-ion battery according to one of claims 7 to 10.

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