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 provides a lithium battery, including a positive electrode current collector, a negative electrode current collector, and an active functional layer. The active functional layer is obtained by mixing a positive electrode active material, a negative electrode active material, and a material that conducts lithium ions, that is, the lithium battery provided by the present invention For the battery, the positive electrode functional layer, separator layer, and negative electrode functional layer separated in the prior art are fused into one layer, so that the contact between layers is transformed into the contact between material particles, which reduces the transmission path of lithium ions and reduces the battery life. The internal resistance can also avoid powder falling due to the change of battery volume.

The invention relates to a composite diaphragm for alkali metal batteries and a preparation method thereof, wherein the composite diaphragm comprises an organic diaphragm base layer coated with a ceramic coating and an amorphous alkali metal ion conductor inorganic solid layer; the preparation method is as follows: The vacuum physical deposition method includes the following steps: pass the organic membrane substrate through the vacuum deposition chamber in a roll-to-roll manner, the vacuum degree of the vacuum box is 0.5-5Pa, the reaction gas is nitrogen, the deposition power is 30-180W, and the deposition time is 5-5Pa After 30 minutes, the composite membrane was deposited. The deposited inorganic solid layer is dense and non-porous, so that the separator has strong mechanical properties and high temperature resistance, which can effectively prevent internal short circuits caused by battery impurities and metal dendrites, as well as thermal deformation of the battery separator. At the same time, the inorganic solid layer has alkali The high-speed conductivity of metal cations, the stability in the air and the barrier function of hetero-ions can significantly improve the safety performance and cycle life of batteries.

The invention discloses a preparation method of a gel polymer lithium ion battery. P(VDF-HFP) is dissolved in an organic solvent, and an in-situ hydrolysis method is used to add inorganic ultrafine powder to prepare the P(VDF-HFP )-TiO2 mixed solution, and then apply the mixed solution to the positive and negative plates of the battery, volatilize the solvent, and form a composite porous film on the positive and negative plates, and then assemble the pole plate and the diaphragm containing the composite porous film, and assemble The liquid electrolyte is injected into the final cell, and the cell is heated and baked, so that the composite porous membrane and the electrolyte form a gel to form a gel polymer battery. The process of manufacturing the polymer battery by the method is simple, the cost is reduced, and the production process is widely applicable; the manufactured composite porous membrane has high liquid absorption rate, high porosity, stable structure, and good battery cycle performance and electrical conductivity.

The invention discloses a composite negative electrode and its preparation method and application, wherein the composite negative electrode includes a metal composite layer and a negative electrode sheet matrix, and the metal composite layer includes a negative electrode material layer and metal nanoparticles infiltrated into the negative electrode material layer; The negative plate substrate has a lithium metal layer, and the metal composite layer is attached to the lithium metal layer. The composite negative electrode uses the alloying confinement effect of metal nanoparticles and lithium ions to control lithium dendrites, delay or inhibit the deposition of lithium ions on the lithium metal layer, and make lithium ions relatively uniformly deposited and nucleated on each channel. and growth, which solves the problem of lithium dendrite growth on the surface of the negative electrode and short circuit in the battery caused by uneven deposition of lithium ions, and can significantly improve the cycle performance, rate performance, safety performance and service life of the battery.

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.