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

The invention provides a non-aqueous electrolyte and a lithium ion battery. The non-aqueous electrolyte comprises a non-aqueous organic solvent, a lithium salt and additives, wherein the additives comprise fluoroethylene carbonate, lithium tetrafluoroborate and a compound as shown in the structural formula 1, wherein in the formula 1, each of the R1-R4 is selected from one kind of H, halogen and saturated and unsaturated alkyl carbon chain with 1-10 carbon atoms; the alkyl carbon chain can be replaced by O or halogen; and the halogen is selected from F, Cl or Br. By virtue of the non-aqueous electrolyte provided by the invention, the high-temperature storage performance of the lithium ion battery can be ensured while the low-temperature cycling performance, the rate discharging performance and the safety performance of the lithium ion battery can be remarkably improved.

The invention discloses a lithium ion battery with improved low temperature charge and discharge performances. A positive material of the lithium ion battery comprises, by mass, 45-47% of a nickel-cobalt-manganese ternary material, 45-47% of lithium manganate, 3-5% of polyvinylidene fluoride, 0.5-1% of conductive carbon black, 1-3% of vapor grown carbon fibers, and 0.5-1.5% of carbon nanotubes. A negative material of the lithium ion battery comprises, by mass, 63-66% of artificial modified graphite, 28-30% of soft carbon, 0.5-1% of conductive carbon black, 0.5-1% of vapor grown carbon fibers, 0.5-1% of carbon nanotubes, 1-2% of carboxymethylcellulose and 2-3% of styrene-butadiene rubber. A diaphragm of the lithium ion battery is a ceramic diaphragm. An electrolyte of the lithium ion battery comprises an electrolyte and a solvent. The electrolyte is lithium hexafluorophosphate. The electrolyte has a lithium hexafluorophosphate concentration of 1-1.2mol / L. The solvent is prepared from ethylene carbonate, dimethyl carbonate, gamma-butyrolactone, methyl acetate and propylene carbonate according to a mass-to-volume ratio of (1-2): (1-2): (0.1-0.3): (0.3-0.5): (0.1-0.3). The lithium ion battery has low internal resistance and good charging and discharging capability in a low temperature state.

The invention discloses an electrolytic solution for improving the low-temperature performance of a lithium ion battery and a lithium ion battery containing the electrolytic solution. The electrolytic solution includes a conductive lithium salt, a non-aqueous organic solvent and an additive. The additive is a multifunctional sulfite compound, and the additive simultaneously contains a sulfite group, a fluorine-containing alkyl group, an ether bond and an allyl group. Among them, the fluorine-containing alkyl group can increase the reduction potential of the additive, making it a good film-forming additive; the allyl group can improve the stability of the positive and negative electrode interfaces; the introduction of ether bonds can improve the flexibility of the electrode interface film, which is beneficial to improve The interface stability of the electrode material; the sulfite group can improve the ionic conductivity of the SEI film, which is beneficial to reduce the impedance of the battery at low temperature, thereby improving the low temperature performance of the battery. The present invention can not only significantly improve the low-temperature cycle performance of the lithium-ion battery by adding such additives in the electrolyte, but also not affect the normal and high-temperature performance of the battery.

The invention belongs to the field of a lithium battery, and discloses a low-temperature lithium battery electrolyte. The low-temperature lithium battery electrolyte comprises an organic solvent, a lithium salt and an additive, wherein the mass ratio of the organic solvent to the lithium salt to the additive is 78-90 to 11.5-15.5 to 1.3-3.7; and the lithium salt of an original low-temperature lithium battery electrolyte only comprises lithium hexafluorophosphate. A small amount of lithium tetrafluoroborate is added to the lithium salt of the low-temperature lithium battery electrolyte provided by the invention; the conductive effect of the lithium tetrafluoroborate is better than that of the lithium hexafluorophosphate, and the addition proportion does not affect the low-temperature performance of the lithium salt; in addition, fluoroethylene carbonate is additionally added to perform a synergistic effect with vinylene carbonate, thereby improving a film-forming effect of the lithium battery, lowering impedance, improving the conduction velocity of electrons and ions at a low temperature, and improving the low-temperature cycle performance of the lithium ion battery; and furthermore, the mass ratios of the components are selected preferably, so that the performance of the electrolyte is more excellent.