61results about How to "Improve overcharge performance" patented technology

The invention provides a formation method used for a lithium ion secondary battery. The method comprises the following steps that: electrolyte is injected into the lithium ion secondary battery and then aged; subsequently, the lithium ion secondary battery is charged; the charging method comprises a first charging process and a second charging process; after the first charging process is completed, the electrolyte is injected into the lithium ion secondary battery again; the injected electrolyte before the first charging process and the electrolyte which is injected into the lithium ion secondary battery after the first charging process respectively and independently are mixed solution which contains the electrolyte lithium salt and the chain-shaped acid ester; wherein, the electrolyte injected into the lithium ion secondary battery before the first charging process also contains film-forming additive; the electrolyte which is injected into the lithium ion secondary battery again after the first charging process also contains overcharging additive. The formation method of the lithium ion secondary battery of the invention can effectively improve the comprehensive electrochemical performance of the battery.

Provided are a positive electrode material for lithium ion batteries and a process for preparing the same. The positive electrode material for lithium ion batteries comprises a composite positive electrode material consists of LiCoO₂ and an auxiliary positive electrode material, the general formula of the auxiliary positive electrode material is LiCo_1−x−yNi_xMn_yO₂, wherein 0<x<0.9, 0<y<0.9, 0<x+y<0.9, and the LiCoO₂ is a modified LiCoO₂ coated with an Al₂O₃ film. The overcharge performance of the batteries can be significantly increased and the use amount of the overcharge additive can be reduced by using the positive electrode material so as to its improve the cycle performance of the batteries and improve the anti-overcharge safety in the special applications and the charging conditions.

The preparation process of artificial graphite charcoal as negative pole material includes the following steps: 1. adding artificial graphite powder and asphalt in the weight ratio of 1.5-19 to 1 while stirring, stirring for further 0.5-3 hr, and adding reaction assistant in 4-20 wt% of graphite powder and asphalt within 10-50 min; 2. heating to 500-600 deg.c in 4-10 hr and pumping out the light component in the first 1-2 hr; 3. maintaining at 500-600 deg.c for 3-8 hr while pumping out the heavy components and reaction assistant; 4. cooling to room temperature and 5. graphitizing. The present invention has environment friendship and high yield, and the prepared artificial graphite charcoal as negative pole material has the advantages of common artificial graphite, the density near that of natural graphite and lowered specific surface area.

The invention provides a high-safety high-energy long-cycle lithium iron phosphate type 18650 lithium battery and a preparation method thereof. The cathode active material of the battery is carbon doped coated lithium iron phosphate with a small particle size and uniform particle size distribution, with the specific capacity being not less than 155 mAh/g and the compaction density being 2.0 - 2.8g/cm<3>; the anode active material is graphite with the specific capacity being 350 - 375 mAh/g and the compaction density being not less than 1. 7 g/cm<3>; a membrane is a PE base membrane coated with a nanometer Al2O3 ceramic membrane. The method comprises the steps of homogenizing, coating, rolling, cutting, winding, shelling, liquid injection, cleaning, oiling, forming and mixing. The batteryenergy density of the invention is as high as 390Wh/L, the discharge capacity of the monomer cell 0.2 C is not less than 2000 mAh, the cycle performance is excellent, the capacity retention rate of the cell 0.5 C/0. 5C100% DOD after 1000 cycles is above 80%, the thermal stability is good, and the overcharge performance is good.

The invention provides a positive active material of a Li-ion battery. The positive active material contains an oxide IA with a formula of LiNi1-x-yCoxMyO2, wherein x and y are mole fractions; the summation of x and y is not less than 0 and less than 1; and M is selected from one or more of a group including Al, B, Mn, Fe, Ti, Mg, Cr, Ga, Cu, Zn, Y, Sr and Nb. The positive active material also contains an oxide IB having a formula of Li(NiMn)(1-a-b)/2CoaXbO2, wherein a and b are mole fractions; the summation of a and b is not less than 0 and less than 1; and X is selected from one or more of a group including Al, B, Fe, Ti, Mg, Cr, Ga, Cu, Zn, Y, Sr and Nb. In addition, the invention also provides the positive active material preparation method. The positive active material has the advantages of excellent thermal stability, rate discharge performance, circle performance and overcharge performance.

A charge storage device (1) includes a sealed prismatic housing (2). Two opposed folded rectangular aluminium electrodes (3, 4) are disposed within housing (2) and connected to respective metal terminals (5, 6) for allowing external electrical connection to the electrodes. A porous, electronically insulating separator material, e.g. Solupor™, sheet separator (7) is disposed intermediate electrodes (3, 4) for maintaining those electrodes in a fixed spaced apart configuration. An electrolyte (not shown) is also disposed intermediate the electrodes. Collecting means in the form of a scavenging agent is grafted to separator (7) for sequestering one or more predetermined contaminants from the housing.

The invention discloses an improved anode material of a lithium ion battery, which is composed of lithium cobaltate and a solid electrolyte layer coating the outer surface of lithium cobaltate, wherein the solid electrolyte layer consists of Li(1+x)AxB(2-x)Si3O12-eN; 0<=x<=2; the A is one of Al, Sc, La, Cr, V, Fe, Tl, Eu and In; the B is Ti, Zr or Hf; and the N is one or combination of more of Li2O, MgO and Y2O3. The invention also discloses a preparation method of the anode material. The material can realize work at higher voltage and remarkably increase the battery capacity, and also greatly improves the cycle performance, the rate capability, the over-charge performance and the safety performance.

The invention provides an anti-overcharging electrolyte based on a ternary lithium ion battery and a lithium ion battery. The anti-overcharging electrolyte is characterized by comprising lithium salt, an organic solvent, an overcharging additive, a salt additive and a function additive, wherein the overcharging additive comprises one or more than two aromatic derivatives A and/or B, the mass of each of the derivatives A and B accounts for 0.01%-5% of the mass of the electrolyte. According to the anti-overcharging electrolyte provided by the invention, Ni-Co-Mn ternary material can be obviously improved, the overcharging performance of the battery particularly under the condition of increase of nickel content can be improved; furthermore, on the premise of improving overcharging, the usage amount of the additives is reduced to the greatest extent (less than 5%), the charging and discharging capacity cannot be affected obviously, a battery DCR is unchanged basically, and the cycling life is not shortened obviously.

The invention relates to the field of lithium ion batteries, and discloses an additive used for a lithium ion battery electrolyte and the electrolyte and the lithium ion battery, wherein the additivecontains an additive a, an additive b and an additive c; the structural formula of the additive a is as shown in structural formula 1; the additive b is at least one of lithium difluorophosphate, lithium difluoroborate and lithium difluorosulfonimide; the additive c is at least one of vinylene carbonate, 1, 3-propane sultone, fluoroethylene carbonate, vinyl vinyl carbonate, glycol sulfite, vinylidene sulfate, propylene sulfite, dimethyl sulfate and trimethylene Sulfite. The additive is mixed by several mixtures, and is applied to the lithium ion battery electrolyte; the electrolyte has excellent overcharge performance, and is excellent in flame retardant property; furthermore, the lithium ion battery using the electrolyte has very small internal resistance and K value, and has relatively good normal temperature circulating performance and high temperature storage property.

A lithium cell of portable electronic apparatus, includes shell, positive active material in the shell, negative active material and electrodes formed by the material, membrane and electrolyte between electrode, whose characteristic is that the positive active material is compound material mixed by lithium-cobalt oxide (LiCoO2) and lithium-manganese oxide (LiMnO4).It can be used as electric powder source in mobile phone, digital photographer digital camera MP3 and another portable electronic apparatus, has low cost and excellent property, solves the problem that lithium cell is prone to expand and increases overcharge property of battery.

The invention belongs to the field of lithium battery materials and particularly discloses a composite thermistor material. The composite thermistor material is characterized by comprising a fullerenematerial, a PTC material and an assistant. The invention further provides a thermistor compounded with the composite thermistor material, a thermosensitive lug assembled by the thermistor and a lithium-ion battery assembled by the thermosensitive lug. The inventor accidentally finds that the performance can be collaboratively improved through combined use of the fullerene material and the PTC material through a large number of studies. The lithium-ion battery with excellent overcharge resistance can be obtained through applying the lug provided by the invention into assembly of the lithium-ion battery; and especially a PTC thermistor containing the fullerene material is added between lugs of a soft package battery, so that the internal resistance of the whole battery can be reduced through reducing the room-temperature internal resistance rate of a PTC, and the overcharge performance of the soft package lithium-ion battery can be effectively improved to enhance the safety performanceof the battery.

The invention discloses a cathode composite active substance for lithium-ion batteries and a preparation method of coating slurry thereof. The cathode composite active substance is composed of LiFePO4 and a Li-Mn oxide in a weight ratio of (92-97): (3-8). According to the cathode composite active substance disclosed by the invention, by using the voltage difference of the two kinds of materials relative to graphite and respective advantages of the materials, the overcharge capacity and low-temperature discharge capacity of a monomer battery are improved, therefore, the cycle life of a battery pack is prolonged, and the energy utilization rate and low-temperature discharge rate of the battery pack can be effectively increased. According to the preparation method of coating slurry provided by the invention, by taking deionized water as a solvent, both finished products can be reduced and the pollution can be reduced, and due to the preparation method, various materials can be uniformly mixed and completely dispersed effectively.

The invention discloses a lithium ion battery and a preparation method thereof. The lithium ion battery comprises a current collector, an active substance layer, a ceramic layer and a polymer microsphere particle layer. The active substance layer is formed on at least part of the surface of the current collector, the ceramic layer is formed on at least part of the surface of the active substance layer away from the current collector, and the polymer microsphere particle layer is formed on at least part of the surface, away from the active substance layer, of the ceramic layer. According to thelithium ion battery, the pole piece coated with the ceramic layer and the polymer microsphere particle layer is adopted, so that the wettability of electrolyte to the pole piece can be effectively improved, thermal shutdown is realized at high temperature, and the overcharge, needling and heating safety performance of the battery is effectively improved.

The invention provides a negative plate with a sandwich structure and a lithium ion battery comprising the negative plate. When a conventional lithium ion battery is subjected to a needling test, an internal short circuit occurs, a large amount of heat is generated in a short time due to relatively large current density of the internal short circuit, thermal shrinkage of a diaphragm is caused, andfinally thermal runaway of the battery is caused. A lithium titanate layer is contained in the negative plate, lithium can be rapidly removed at the moment of internal short circuit to form an air-state insulator, the resistance of the negative plate is sharply increased in the process, the short-circuit current can be reduced, and then the needling safety of the lithium ion battery can be improved. A silicon material layer is contained in the negative plate, lithium dendrites can be consumed through reaction when the silicon material layer makes contact with the lithium dendrites, the situation that the negative plate seriously separates out lithium to form a large number of lithium dendrites in the overcharge process of the battery cell is avoided, and internal short circuit caused by the fact that the lithium dendrites pierce a diaphragm is further avoided.

The invention discloses an electrolytical lithium salt and a lithium ion battery electrolyte containing the electrolytical lithium salt. The chemical formula of the electrolytical lithium salt is LiC11H6BO3F2; and the structural formula is shown in the specification. The lithium ion battery electrolyte contains a nonaqueous organic solvent, an additive and the electrolytical lithium salt, wherein the content of the electrolytical lithium salt accounts for 0.01-15% of the total weight of the electrolyte. According to the invention, through the introduction of the electrolytical lithium salt LiC11H6BO3F2, the comprehensive performance of the lithium ion battery electrolyte is improved; due to the lithium ion battery electrolyte, the charge and discharge capacities, coulombic efficiency and long cycle performance of a battery can be significantly improved; and the internal resistance of the battery is reduced to some extent. In addition, the lithium ion battery electrolyte containing the electrolytical lithium salt has a good overcharge performance.