32results about How to "Avoid internal short circuit" patented technology

The present invention discloses a positive electrode current collector, a positive electrode sheet and an electrochemical device. The positive electrode current collector comprises a support layer having two opposite surfaces in the thickness direction thereof and a conductive layer disposed on at least one of the two surfaces of the support layer; wherein the thickness D1 of the conductive layeris greater than or equal to 300nm and less than or equal to 2mu m, and preferably, the thickness D1 is greater than or equal to 500nm and less than or equal to 1.5 mu m; and when the tensile strain ofthe positive electrode current collector is greater than or equal to 3%, the square resistance growth rate T1 of the conductive layer is greater than or equal to 50%. The positive electrode current collector provided by the invention can give consideration to relatively high safety performance and electrical performance at the same time, so that the positive electrode piece and the electrochemical device adopting the positive electrode current collector can give consideration to relatively high safety performance and electrochemical performance at the same time.

The invention belongs to the technical field of lithium ion batteries, and specifically relates to a high-energy-density ternary NCA battery and a preparation method thereof; the high-energy-density ternary NCA battery includes a positive electrode material, a negative electrode material and an electrolyte, and the high-energy The preparation method of the density ternary NCA battery includes the following steps: 1) preparation of the positive electrode sheet; 2) preparation of the negative electrode sheet; 3) preparation of the electrolyte; 4) production of the finished battery; the improvement of the negative electrode material will increase the coating uniformity High quality and high density, will not cause local cracks in the cycle, inhibit the appearance of new surfaces, reduce side reactions, reduce the formation of new SEI films, improve the effective use of silicon, and achieve a stable material structure with ternary NCA cathode materials , improve its normal temperature, high temperature cycle performance and thermal stability; at the same time, add positive electrode surface protection agent, lithium hexafluorophosphate stabilizer and negative electrode SEI film forming additive to the electrolyte to improve battery safety and high temperature cycle life.

The invention discloses a ceramic and polymer composite coated lithium ion diaphragm and a preparation method thereof, comprising a polyolefin porous diaphragm, a ceramic coating coated on one side or both sides of the diaphragm surface, and a ceramic coating coated on the ceramic surface or the diaphragm surface. polymer coating, the composite diaphragm prepared by the present invention greatly improves the heat resistance of the diaphragm, improves the infiltration of the electrolyte, improves the bonding strength between the diaphragm and the positive and negative electrodes, and prevents the diaphragm and the electrode from being interlayered. The resulting internal short circuit increases the hardness of the battery at the same time, and the safety performance of the battery is greatly improved. Moreover, in the production process, the ceramic coating and the polymer coating have uniform thickness and good uniformity, which is conducive to continuous and large-scale production.

The invention discloses a polymer lithium ion battery and a preparation method of a diaphragm of the polymer lithium ion battery. The preparation method comprises the following steps: dissolving P(VDF-HFP) into an organic solvent, and adding inorganic ultra-fine powder into the mixture by adopting an in-situ hydrolysis method so as to prepare a mixed solution of P(VDF-HFP)-TiO2; coating the mixed solution on a polyolefin diaphragm so that the solvent is volatilized and a composite porous membrane is formed on the diaphragm; then assembling positive and negative pole pieces with the diaphragm; injecting liquid electrolyte into an electric core after assembling; and heating and baking the electric core so that the composite porous membrane and the electrolyte form a gel so as to prepare a gel polymer battery. The method has a simple technological process for preparing the polymer battery, low cost and wide application range of a production process; and the manufactured composite porous membrane has the advantages of high liquid absorption rate, high porosity and stable structure, and the battery has good cycling performance and electric conductivity.

A nanotube of transition metal sulfide (MSx, where M is Ti, Sr, Nb, Mo, W, etc and X=1 or 2) is prepared by low-temp gas-solid catalytic reaction. The said nanotube has unique laminated tubular structure and large specific surface area, and can be used as the hydrogen bearing or lithium bearing electrode of battery as it has high change-discharge speed and excellent cycle life.