Sep 19, 2019 Pageview：135
The lithium battery before the production process can be divided into sheet manufacture, the tathagata batteries after encapsulation, the Tao battery activation of three phases, cell activation stage is for the purpose of the live material and electrolyte in the battery been fully activated in order to achieve stable electrochemical performance.Activation stage includes preliminary charging, into, aging, such as constant volume phase.Beforehand and charging into the anode materials is carried out is for the purpose of the first few times of charging and discharging to activate the materials, the use of materials in the best state.
Several main aim of the aging: one is for more good electrolyte of infiltration, is conducive to the stability of the battery performance.Second, positive active material of cathode materials after aging, can spur some side effects, such as gas, electrolyte decomposition, let the electrochemical performance of lithium-ion batteries quickly achieve stability;3 it is lithium battery consistency through aging after a period of time.Into after the batteries voltage is not stable, the measured value will deviate from the actual values, the batteries voltage, internal resistance after aging is more stable, is advantageous for the screening of high consistency of the battery.
Aging system on the properties of the lithium battery has two main influence factors, namely, aging temperature and aging time.In addition, with aging cells in sealing or opening state is more important.
For opening into, if factory can control the humidity aging after sealing.If the high temperature aging, aging after sealing is better.For different battery system, three yuan positive/graphite anode of lithium batteries, lithium iron phosphate anode/graphite cathode lithium battery or lithium titanate battery, need according to the material properties and features of the lithium battery test.In the design of experiment, can through the lithium battery capacity difference, resistance difference and pressure drop characteristics to determine the optimal aging system.
Three yuan a, or the positive/lithium iron phosphate graphite anode of lithium battery
For three yuan as the anode material, graphite as anode materials for lithium batteries,Lithium ion batteriesPrefi lled into phase will be formed on the surface of graphite anode (SEI), a layer of solid electrolyte membrane around the the formation of the membrane potential of 0.8 V, SEI allow ions to penetrate and do not allow electronic through, resulting in the formation of certain thickness could suppress after further decomposition of the electrolyte, can rise to prevent battery performance decline caused by the electrolyte decomposition.But turned to the formation of the SEI film structure closely and pore is small, the battery for aging, will help the SEI restructuring, forming loose and porous membrane, in order to improve the performance of lithium-ion batteries.
Three yuan/graphite lithium battery aging generally choose the normal temperature aging - 28 days to 7 days, but also some factory using high temperature aging system, aging time for 1-3 days, the so-called high temperature is usually between 38 ℃ to 50 ℃.High temperature aging just in order to shorten the production cycle, the purpose and the normal temperature aging, is let is negative, the diaphragm, sufficient for chemical reactions such as electrolyte balance, let lithium battery to achieve a more stable state.
Two lithium batteries, lithium titanate cathode
Commonly known as theTitanium acid lithium batteryIs the cathode adopted lithium titanate battery, anode materials mainly three yuan, such as cobalt acid lithium materials.Lithium titanate differences with graphite cathode battery is lithium titanate intercalated-li potential is 1.55 V (relative to the lithium metal), higher than that of the SEI formation of 0.8 V, so the process of charging and discharging can't form a solid electrolyte film (SEI) can't lithium dendrite formation, which has higher security.
This means that the lithium titanate charging process, constantly have electrons react with the electrolyte, generating by-products and produce the gas such as hydrogen, CO, CH4, C2H4, can lead to a bulge of the battery.Lithium titanate bulge problem mainly depends on the changing nature of the material to ease, such as surface coating material, change the particle size distribution, finding the right electrolyte, etc.
In addition, through optimizing prefi lled, into, aging system of lithium titanate can be appropriately reduced bulge phenomenon.Lithium titanate battery aging system choice in high temperature aging system, aging temperature using 40 ℃ to 55 ℃, aging time is usually 1-3 days, the need for negative pressure exhaust after aging.Dozens of times and high temperature aging, make the battery internal moisture full reaction, the gas discharge after titanate can effectively restrain the flatulence of lithium-ion batteries, improve its cycle life.
No matter what kind of system for battery, aging is a process with the necessary.Lithium battery aging while understanding it is loss and damage of lithium battery, but in fact it is screening of high consistency of the battery, the effective ways to eliminate non-conforming.Only through the way of aging, can choose the suitable for package set of lithium batteries, increase the service life of electric tools.
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