53results about How to "Improve low temperature cycle performance" patented technology

The present invention discloses a preparation method of the difluoride lithium oxalate borate. The method is characterized in that the compounds containing the fluorin, boron, lithium and oxalate react at a certain temperature and under a certain pressure to produce the crude material of the difluoride lithium oxalate borate; then the organic solvent is used for extracting and purifying; finally, the recrystallization and vacuum drying are done to get the battery-level lithium fluoride oxalate borate. The advantage is that the preparation method of the difluoride lithium oxalate borate can improve the high-temperature and low-temperature performance, the cycle performance, power characteristics and other comprehensive performances of the lithium-ion battery.

The invention relates to a lithium ion battery electrolyte and a lithium ion battery, and belongs to the technical field of lithium ion batteries. The lithium ion battery electrode comprises an organic solvent, an electrolyte lithium salt, a low-impedance additive and a functional additive, wherein the low-impedance additive comprises lithium difluorophosphate and lithium difluoro bis(oxalato) phosphate, the functional additive is an arbitrary one or a combination of tris(trimethylsilyl) borate and tris(trimethylsilyl) phosphate, and the functional additive accounts for 0.1-4% of the total mass of the lithium ion battery electrolyte. The lithium ion battery electrolyte can participate in negative electrode film formation, the interface impedance of the electrolyte is reduced, and the low-temperature performance of the electrolyte is improved; and a flexible and high-temperature stable electrode interface film also can be formed on a surface of a high-capacity silicon carbon composite negative electrode material, the breakage of an SEI film caused by silicon expansion during the circulation process is timely repaired, and the cycle property of the silicon carbon negative electrode lithium ion battery is improved.

The present invention relates to the field of lithium ion batteries, and particularly to a step-by-step charging method for a lithium ion battery. The method comprises the following steps: 1, adopting a current Ia to carry out constant current charging on a battery to a capacity of Capa, wherein a standing time is ta; 2, adopting a current Ib to continuously carry out constant current charging on the battery to a capacity of Capb, wherein a standing time is tb; 3, adopting a current Ic to continuously carry out constant current charging on the battery to a capacity of Capc, wherein a standing time is tc; and 4, adopting a current Id to carry out constant current charging on the battery to a specified potential, and then carrying out constant voltage charging on the battery under the specified potential. According to the present invention, high temperature and low temperature performances of the battery can be improved without change of the original structure of the battery; and a high charging state can be achieved in a short time while temperature increase of the surface of the battery is relatively uniform so as to reduce temperature increase due to polarization during a rapid charging process and influence on battery performances by lithium precipitation.

The invention relates to the field of energy storage materials, in particular to an electrolyte solution and a battery applying the electrolyte solution. The electrolyte solution is prepared from thefollowings: an electrolyte, an organic solvent and an additional agent, the organic solvent contains sec-butyl methyl carbonate, and thus the discharge capability of the battery at the low temperatureand the storage performance of the battery at the high temperature can be improved. In the optimized technical scheme, at least one of compounds including S=O groups can be further added into the electrolyte solution, the compounds including the S=O groups as the additional agent cooperates with the sec-butyl methyl carbonate, and thus the low-temperature circulating performance of the battery can be further improved.

The invention relates to the technical field of lithium batteries, inp articular to a low-temperature cycle iron phosphate lithium-ion power battery and a preparation method of the low-temperature cycle iron phosphate lithium-ion power battery. The low-temperature cycle iron phosphate lithium-ion power battery comprises a positive electrode, a negative electrode and an electrolyte, the positive electrode comprises lithium iron phosphate, the average particle size distribution D50 of the volume of the lithium iron phosphate is 0.5-2 [mu]m, the tap density of the lithium iron phosphate is 0.8-1.5 g/cm<3>, the specific surface area of the lithium iron phosphate is 6-12 m<2>/g, the negative electrode comprises a green coke pulverized super-high temperature graphitized material, the particle size distribution D50 of the green coke pulverized super-high temperature graphitized material is 2-10 [mu]m, the tap density of the green coke pulverized super-high temperature graphitized material is1.2-2 g/cm<3>, and the specific surface area of the green coke pulverized super-high temperature graphitized material is 0.5-1.5 m<2>/g. The positive electrode and the negative electrode are modified,so that the low-temperature cycle performance of the lithium battery is improved.

The invention relates to a lithium secondary battery electrolyte solution and a lithium secondary battery containing the lithium secondary battery electrolyte solution. The lithium secondary battery electrolyte solution is prepared from organic solvent, conductive lithium salt, ionic liquid and additives; the ionic liquid is selected from at least one of 1-ethyl-3-methyl imidazolium tetrafluoroborate and 2-pyrrolidyl ammonium tetrafluoroborate. According to the electrolyte solution, by adding the ionic liquid including the 1-ethyl-3-methyl imidazolium tetrafluoroborate and the 2-pyrrolidyl ammonium tetrafluoroborate and the additives including lithium difluorophosphate, 2-propinyl methyl carbonate, allyl methyl carbonate and 1,3-propane sultone in a combined mode, the high temperature cycle performance, the normal temperature cycle performance and the low temperature cycle performance of the electrolyte solution can be improved.

The invention belongs to the technical field of lithium ion batteries, and discloses a wide-temperature type lithium ion battery electrolyte and a lithium ion battery containing the electrolyte. The wide-temperature type lithium ion battery electrolyte comprises a lithium salt, an organic solvent and an additive, and the additive comprises a chain-like acyl sulfonate compound with a structure shown in a formula I or a cyclic acyl sulfonate compound with a structure shown in a formula II, the acyl sulfonate additive can be simply regarded as an anhydride compound formed by dehydration of carboxylic acid and a sulfonic acid group, has both the anhydride group and the sulfonic acid group, can form an SEI membrane component with a lithium alkyl sulfonate or lithium alkyl sulfate structure, isresistant to high temperature, can improve the high-temperature stability of the lithium ion battery, is low in impedance and has a good low-temperature effect, and the normal-temperature and low-temperature cycle performance of the lithium ion battery can be improved.

The invention belongs to the technical field of lithium ion batteries, and discloses a high-voltage electrolyte containing a sulfate lithium salt additive and a lithium ion battery containing the electrolyte. The high-voltage electrolyte containing the sulfate lithium salt additive comprises lithium hexafluorophosphate, an organic solvent and an additive, the organic solvent comprises one or more of chain carbonic esters, cyclic carbonic esters and carboxylic esters, and the additive comprises a sulfate lithium salt compound. The sulfate lithium salt compound has good high temperature resistance, can form a smooth and uniform film on the surface of an electrode, prevents further oxygenolysis of the electrode and an electrolyte, and reduces gas generation expansion of the battery after high temperature placement; meanwhile, the membrane has good permeability to lithium ions, impedance increase caused by membrane formation can be reduced, the conductivity of electrolyte in the lithium ion battery is effectively improved, and the cycle performance of the lithium ion battery is improved.

The invention provides an electrolyte and a secondary battery. The electrolyte comprises electrolyte salt, organic solvents and additives; the additives comprise one or multiple in the compounds as shown in formula. After the electrolyte of the invention is applied to the secondary battery, the normal temperature and low temperature cycle performance, the high temperature storage performance and the hotbox security performance can be effectively improved.

The invention belongs to the field of lithium ion batteries and discloses a lithium ion battery, a cathode sheet thereof, a cathode material, and a preparation process. The cathode material comprisesa cathode active material, a conductive agent, lithium lanthanum-zirconium oxide, and a binder; the mass percentages of the cathode active material, the conductive agent, the lithium lanthanum-zirconium oxide and the binder are 95%-6%, 0.2%-0.6%, 0.2%-0.6%, and 2.8%-3.4% respectively. With the technical schemes of the invention adopted, the improvement of low temperature performance of the lithiumion battery can be benefitted.

The present invention relates to a composition, an electrolyte containing the composition, and a lithium ion battery, the composition comprises a first component and a second component, the first component comprises at least one sulfur-containing compound having a structure represented by a formula (I), and the second component comprises at least one cyclic carbonate compound having a structure represented by a formula (II); and the composition can be added into an electrolyte as an additive, and can effectively improve the high-temperature and low-temperature performance of the battery.

The invention discloses a high-voltage-resistant low-temperature lithium ion electrolyte, and belongs to the technical field of electrochemical energy storage. The lithium ion electrolyte comprises a main solvent, a diluent, a film-forming additive and a lithium salt, the main solvent accounts for 20-40% of the total mass of the electrolyte, the diluent accounts for 40-65% of the total mass of the electrolyte, the film-forming additive accounts for 5-15% of the total mass of the electrolyte, and the lithium salt accounts for 8-15% of the total mass of the electrolyte. The lithium ion electrolyte, the main solvent and the diluent act on the solvation structure of the lithium ion, so that the lithium ion has small desolvation energy, and when the lithium ion electrolyte is applied to the lithium ion battery, the lithium ion battery can show excellent low-temperature discharge performance and low-temperature cycle performance.

The invention discloses a lithium ion battery electrolyte capable of improving high and low temperature cycle performance and a lithium ion battery. The lithium ion battery electrolyte comprises a sulfur-containing polyfunctional electrolyte additive, and the sulfur-containing polyfunctional electrolyte additive is lithium dithiooxalatoborate or lithium dithiooxalatophosphate. On one hand, oxalategroups in the additive can be oxidized, reduced and polymerized on the surface of an electrode material to form a uniform and compact solid electrolyte membrane. On the other hand, the additive contains part of sulfur atoms, so that sulfide components with high ionic conductivity can be promoted to be formed in the solid electrolyte membrane. Therefore, the lithium ion battery electrolyte containing the additive can improve the high-temperature and low-temperature cycle performance of the lithium ion battery at the same time, and compared with the traditional electrolyte containing the oxalicacid lithium phosphate or lithium borate additive, the lithium ion battery electrolyte containing the additive is lower in film forming impedance and better in battery cycle performance.

The invention discloses a low-temperature-resistant lithium-ion battery long in service life. The median particle diameter D50 of an active material at the positive electrode of the lithium-ion battery is larger than or equal to 5.5 micrometers and smaller than or equal to 10 micrometers, the negative electrode is composed of a modified graphite material, and a low-temperature additive is added into an electrolyte solution. The lithium-ion battery has excellent low-temperature charging and discharging performance and has a long cycle life at the low temperature, and the lithium-ion battery can be used as an energy storage battery or an electric vehicle battery in the low-temperature environment.

The invention discloses an electrolyte for improving low-temperature performance of a lithium ion battery and the lithium ion battery containing the electrolyte. The electrolyte comprises conductive lithium salt, a non-aqueous organic solvent and an additive, the additive is a polyfunctional sulfite compound, and the additive contains sulfite groups, fluorine-containing alkyl, ether bonds and allyl at the same time. The fluorine-containing alkyl can improve the reduction potential of the additive so that the additive becomes a good film-forming additive; allyl can improve the stability of positive and negative electrode interfaces; the introduction of the ether bonds can improve the flexibility of an electrode interface film, and is beneficial to improving the interface stability of an electrode material; and the sulfite groups can improve ionic conductivity of an SEI film, and are beneficial to reducing the impedance of the battery at a low temperature so that the low-temperature performance of the battery is improved. By adding the additive into the electrolyte, the low-temperature cycle performance of the lithium ion battery can be obviously improved, and the normal-temperatureperformance and the high-temperature performance of the battery are not influenced.

The invention provides an electrolyte and a lithium ion battery comprising the same. The electrolyte adopted by the invention comprises a non-aqueous organic solvent, an electrolyte lithium salt and an electrolyte functional additive, the electrolyte functional additive comprises a first additive and a second additive, the first additive is selected from at least one of organic germanium compounds, and the second additive is at least one of lithium salt compounds and/or at least one of cesium salt compounds. The first additive and the second additive are used as film-forming additives to form a compact SEI film dominated by inorganic matters such as an organic germanium compound, a lithium salt or a cesium salt and the like through reaction at the early stage of battery circulation, and the SEI film not only has the effect of inhibiting the subsequent electrolyte decomposition reaction, but also has the effect of inhibiting the electrolyte decomposition reaction; and the two-phase interface impedance of the electrode/electrolyte is further reduced, and conduction of lithium ions on a solid/liquid two-phase interface is promoted.

The invention provides a formation method of a lithium ion battery. An electrolyte of the lithium ion battery comprises linear carbonic ester, cyclic carbonic ester, electrolyte salt and additives, wherein the additives comprise fluoroethylene carbonate, divinyl sulfone and alpha, alpha-dimethyl-gamma-butyrolactone. The formation method comprises the following steps: injecting the electrolyte intoa to-be-injected battery, carrying out constant-current charging to a first predetermined voltage, then carrying out pulse charging and discharging circulation between the first predetermined voltageand a second predetermined voltage for multiple times, vacuumizing and exhausting during the pulse charging and discharging circulation, then carrying out constant-current charging to a charging cut-off voltage, standing, then charging and discharging for a plurality of times at the charging cut-off voltage and the discharging cut-off voltage, vacuumizing, exhausting, and sealing to obtain the battery. The lithium ion battery obtained by the formation method disclosed by the invention has good high-temperature performance and low-temperature performance.

The invention provides a niobium-doped lithium titanate material, a preparation method thereof and a lithium battery. The niobium-doped lithium titanate material has the following structural general formula: Li4Ti(5-x)NbxO12, wherein 0<x<=0.2, D50 of the niobium-doped lithium titanate material is 7-11 microns, and BET specific surface area of the lithium titanate material is 3.0-5.3 m<2>/g. The niobium-doped lithium titanate material has a rich pore structure, the migration distance of lithium ions in the material is effectively shortened, and the diffusion impedance is reduced. The porous lithium titanate material with relatively large specific surface area increases the infiltration area of an electrolyte, so that more de-intercalation sites are provided for lithium ions, polarization is reduced, the diffusion rate of the lithium ions is improved, the specific capacity, the energy density and the rate capability of the lithium ion battery are further improved, and the low temperature resistance of the lithium ion battery is further improved.

The invention discloses a lithium ion battery electrolyte used at low temperature. The electrolyte comprises a lithium salt, an additive and a non-aqueous organic solvent, wherein the lithium salt is a composite lithium salt of a phosphoric acid lithium salt, a sulfimide lithium salt and a boric acid lithium salt, the additive is selected from fluoroethylene carbonate and ethoxy(pentafluoro)cyclotriphosphazene, and the non-aqueous organic solvent comprises a carbonic ester solvent and a linear carboxylic ester solvent. By matching the linear carboxylic ester solvent with low freezing point and low viscosity with the carbonic ester solvent, the viscosity of the electrolyte is reduced, the interfacial compatibility of the solvent and a graphite negative electrode is maintained, meanwhile, a lithium salt system is adjusted, the low-temperature lithium ion conductivity of the electrolyte is improved, and the low-temperature rate performance of a lithium ion battery is improved; in addition, various additives are added, so that a stable interfacial film is formed, and the low-temperature cycle and rate performance of the lithium ion battery are improved.

A battery comprises an electrode assembly and an electrolyte solution, wherein the electrode assembly comprises an anode plate, a cathode plate, and a separator located between the anode plate and the cathode plate. The electrolyte solution comprises a lithium salt and an organic solvent, wherein the organic solvent comprises a chain carboxylic ester compound, with the mass ratio of the chain carboxylic ester compound in the organic solvent being 10%-70%. The separator comprises a substrate, a first coating and a second coating, wherein the substrate comprises a first surface and a second surface, which are opposite each other; and the first coating and the second coating are respectively disposed on the first surface and the second surface. The first coating faces the anode plate; the second coating faces the cathode plate; the first coating comprises a first binder; the second coating comprises a second binder; and the average particle size of the second binder is greater than that of the first binder. The battery of the present application can take into consideration both high low-temperature cycle performance and high high-temperature cycle and storage performance. Further provided is an electronic device comprising the battery.

The invention provides a negative pole piece and application thereof.The negative pole piece comprises a current collector and a negative pole material layer arranged on the surface of the current collector, the negative pole material layer comprises a carbon-based material, and the carbon-based material comprises a primary granular carbon material, a secondary granular carbon material and a carbon coating layer coating the surface of the secondary granular carbon material; the value of the performance factor i of the negative pole piece is 0.2-10, and the expression of the performance factor i is shown in the specification; wherein SSA is the specific surface area value of the carbon-based material, and the unit corresponding to the specific surface area value is m < 2 >/g; dv10, Dv50 and Dv90 are corresponding particle size values when the volume percentage of the carbon-based material reaches 10%, 50% and 90% respectively, and the unit corresponding to the particle size values is [mu] m; p is the porosity value of the negative electrode material layer; iD/IG is the peak height ratio of the D peak to the G peak of the Raman spectrum of the carbon-based material.