11results about How to "Improve low temperature discharge performance" patented technology

The invention relates to the technical field of lithium ion batteries, in particular to an ultralow-temperature electrolyte and a lithium ion battery comprising the same, the electrolyte comprises a lithium salt, an organic solvent and an additive, and the organic solvent comprises cyclic carbonate and carboxylic ester; the lithium salt comprises lithium hexafluorophosphate and sulfonyl imide salt of at least one selected from lithium bis (fluorosulfonyl) imide or lithium bis (trifluoromethane) sulfonyl imide. The lithium ion battery comprises a positive pole piece, a negative pole piece, electrolyte and a diaphragm, the negative pole piece comprises a negative pole material layer containing a negative pole active material, and the negative pole active material comprises a silicon-based material and a carbon material; the lithium ion battery satisfies the following conditions: 0.2 < = (0.01 * E + D) / (S + 10 * L) < = 3.5, 500 < = E < = 1200, 2 < = D < = 50, 15 < = S < = 35, 0.1 < = L < = 0.5; in order to meet the requirement of high gram volume in a low-temperature environment, the negative pole piece with high gram volume and low resistivity is adopted, and the composition of the solvent and the lithium salt is regulated and controlled, so that the electrolyte still has relatively high ionic conductivity and low viscosity characteristics in the low-temperature environment, and the low-temperature charge-discharge performance of the lithium ion battery is further effectively improved.

The invention relates to a modified graphite negative electrode material and a preparation method thereof, a negative electrode and a lithium ion battery. The modified graphite negative electrode material comprises graphite particles and an SEI precursor layer which is uniformly coated on the surface of each graphite particle and is constructed by lithium salt, wherein the lithium salt is of a crystalline state structure, and the thickness of the SEI precursor layer is 1-500 nm; during the first charging and discharging process of the battery, the lithium salt of the SEI precursor layer is subjected to electrochemical reaction prior to electrolyte, and an inorganic phase SEI with LiF and / or Li3PO4 as a main component is formed on the surface of graphite particles in situ. The negative electrode material disclosed by the invention realizes active formation and uniform distribution of SEI, even in a thick electrode, a continuous SEI layer can be formed on the surface of a deep graphite particle in the first charge-discharge and cycle process of a battery, the first-cycle coulombic efficiency is remarkably improved, the cycle life is remarkably prolonged, and the low-temperature and rate performance is improved; in addition, the electrolyte can more easily infiltrate the electrode, so that Li < + > is more smoothly transmitted in the thick electrode, and the electrochemical performance of the electrode is improved.

This invention relates to the field of battery technology, specifically to a lithium-ion secondary battery. The lithium-ion secondary battery includes an electrode assembly, which includes a positive electrode sheet. The positive electrode sheet includes a positive current collector, a positive active layer, a protective layer, and a surface coating layer. The positive active layer is located on at least one side surface of the positive current collector, the protective layer is located between the positive current collector and the positive active layer, and the surface coating layer is located on the outer surface of the positive active layer away from the positive current collector. The thickness of the surface coating layer containing a solid electrolyte is 'a', where 'a' is 0.5 μm to 5 μm; the thickness of the protective layer is 'b', where 'b' is 0.2 μm to 5 μm; 0.1 ≤ a / b ≤ 10. The negative electrode sheet includes a negative current collector and a negative active layer comprising silicon-carbon material. One side outer surface of the positive electrode sheet has several protrusions. The lithium-ion secondary battery of this invention combines high energy density, low-temperature discharge performance, and needle penetration safety performance.

The invention provides a secondary battery and electric equipment. The secondary battery comprises a positive pole piece and an electrolyte, the positive pole piece comprises a positive current collector and a positive active material layer arranged on at least one surface of the positive current collector, the positive active material layer comprises a positive active material, the positive active material comprises lithium iron phosphate, and the lithium iron phosphate comprises secondary particles formed by gathering primary particles. The average particle size of the primary particles is D nm, the specific surface area of the lithium iron phosphate is BET m < 2 > / g, and D / BET is greater than or equal to 2 and less than or equal to 30; the electrolyte comprises an additive and an organic solvent, the additive comprises lithium fluorosulfonate, the mass percentage of the lithium fluorosulfonate in the electrolyte is a%, 0.05 < = a < = 0.5, the organic solvent comprises ethyl propionate, and the mass percentage of the ethyl propionate in the organic solvent is greater than or equal to 30%. The low-temperature discharge performance, the high-temperature storage performance and the high-temperature cycle performance of the secondary battery are improved by matching the proper positive electrode active material and the electrolyte.

The invention relates to a high-nickel ternary positive electrode material, a preparation method of the high-nickel ternary positive electrode material, a positive plate and a battery. The high-nickel ternary positive electrode material comprises secondary particles formed by aggregating primary particles, the high-nickel ternary positive electrode material satisfies the following conditions: in the primary particles of the secondary particles, the ratio A [101] / A [104] of the total surface area A [101] of the [101] crystal face to the total surface area A [104] of the [104] crystal face satisfies 0.05 < = A [101] / A [104] < = 0.3; the concentration of the cobalt element in the secondary particle is in gradient distribution which is sequentially decreased from the surface to the center, and the cobalt element concentration C [surface] in the surface area of the secondary particle and the cobalt element concentration C [core] in the core area of the secondary particle meet the condition that (C [surface]-C [core]) / C [core] is larger than or equal to 0.05 and smaller than or equal to 0.2. According to the scheme provided by the invention, the low-temperature discharge capacity, the high-temperature storage stability and the long cycle life of the ternary material can be synergistically improved.

This invention belongs to the field of secondary batteries, and provides a novel structural additive, a preparation method, a non-aqueous electrolyte containing the novel structural additive, and a secondary battery. The novel structural additive is a complex of an inner salt compound containing a hydrocarbon sulfonate anion and a quaternary ammonium cation with difluorophosphate, having the structure shown in Formula I: where R1 is a hydrocarbon-like group with 1-6 carbon atoms; R2 is a chain-like or cyclic quaternary ammonium cation; R3 and R4 are independently selected from one of , , , , or ; R5, R6, and R7 are independently selected from hydrocarbon groups or hydrocarbon oxygen groups; R8, R9, and R... 10 The elements are independently selected from hydroxyl groups; n=1~6, m=1~6, p=1~6, and n, m, and p are independent of each other; M is a metallic element selected from Li or Na. A non-aqueous electrolyte and a secondary battery containing this novel structural additive are provided, which can improve the battery's low-temperature discharge performance and high-temperature storage performance, and extend cycle life.

The application provides a battery and a power utilization device, a positive electrode sheet comprises a positive electrode active material, the positive electrode active material is doped and / or coated with a lanthanum element; a separator surface is coated with a ceramic coating; an electrolyte comprises a first solvent, a second solvent, a first additive and a second additive; the first solvent comprises a cyclic carbonate compound, the second solvent comprises a chain fluorosulfonamide compound, the first additive comprises mannitol carbonic acid sulfate, and the second additive comprises succinonitrile; by doping / coating the positive electrode active material with the lanthanum element, the application can effectively inhibit the release of lattice oxygen under high voltage or high temperature, and reduce the exothermic reaction activity at the thermal runaway starting temperature; the first additive and the second additive in the electrolyte form a dense, high-thermal-stability CEI film and SEI film on the positive and negative electrode surfaces respectively; the separator ceramic coating provides a physical barrier, improves the thermal shrinkage temperature of the separator, and prevents internal short circuit.

The application provides a lithium iron phosphate positive electrode active material, a preparation method of the lithium iron phosphate positive electrode active material, a positive electrode sheet, a battery, a battery pack and an electric device. 16 spins / g~2.0000×10 16 spins / g. The lithium iron phosphate positive electrode active material provided by the application has a high compaction density and has normal temperature rate discharge and low temperature discharge performance.

The invention provides an electrolyte and a secondary battery. The electrolyte comprises a solvent, an electrolyte and an additive, wherein the additive comprises a first component and a second component; the first component is selected from fluoroethylene carbonate, the second component is selected from a compound shown as a formula I, based on the mass of the electrolyte, the mass percentage content of the first component is a, a is more than or equal to 5% and less than or equal to 20%, the mass percentage content of the second component is b, and b is more than or equal to 0.1% and less than or equal to 2%. The synergistic effect of the first component and the second component can improve the high-temperature cycle performance, the high-temperature storage performance and the low-temperature discharge performance of the secondary battery and reduce the impedance.

This invention discloses a negative electrode sheet and a lithium-ion battery. The negative electrode sheet includes at least two sets of active units coated sequentially from one side of a negative electrode current collector. Each set of active units includes a graphite negative electrode layer and a hard carbon negative electrode layer coated sequentially from the inside out. The graphite negative electrode layer has multiple pores spaced apart on the side adjacent to the hard carbon negative electrode layer, and hard carbon negative electrode material for forming the hard carbon negative electrode layer is embedded within these pores. The pore capacity between each set of active units increases sequentially from the inside out. This invention, by optimizing the negative electrode sheet structure, can significantly improve the low-temperature charge-discharge cycle performance of the battery. This multi-layer negative electrode sheet has the advantages of high charging efficiency and strong low-temperature charge-discharge capability, which can significantly improve the high-rate charge-discharge performance of lithium-ion batteries and extend the electrode life under high-rate charge-discharge conditions.

The application discloses an electrolyte, a secondary battery and a power utilization device, and belongs to the battery field. The electrolyte comprises a first additive, and a chemical structural formula of the first additive comprises a heterocyclic ring and a thiourea group. The electrolyte disclosed by the application can improve the high-temperature storage performance, low-temperature discharge performance and cycle performance of the battery.