News_News_Jiangxi Rendong New Energy Co., Ltd.

01-15 

When were lithium-ion batteries introduced?

Some people started seeing these lithium-ion batteries at their tender ages. I am sure that a significant percentage of people do not know even it was introduced. However, others have a lot of knowledge about this fantastic product. It was introduced in 1991 by Sony Corporation. It had undergone many tests, and several bodies certified that it was safe for human use. They were designed for use on portable devices and electric vehicles. The batteries have grown popular over time, and the world cannot be comfortable without them. Akira Yoshino made a Prototype of lithium-ion batteries in 1985. Still, it was based on research done by John Goodenough, M. Stanley Whittingham, Rachid Yazami, and Koichi Mizushima in the 1970s and 1980s. However, Sony and Asahi Kasei developed a lithium-ion battery for commercial purposes in 1991, with Yoshio Nishi being their leader. They used the intercalated lithium compound as the positive electrode's material and graphite as the negative electrode. Lithium-ion batteries became famous because of their high energy density, no memory discharge, and low self-discharge. Lithium-ion batteries vary in their chemistries, performance, cost, and safety characteristics. Despite being in existence for three decades now, the battery is still undergoing significant improvements to make it much better. The research areas targeted by experts include increasing energy density, reducing, increasing charging speed, extending lifetime, and improving safety, among other vital areas. The incredible thing is that the Nobel Prize in chemistry 2019 was given to three outstanding scientists who made significant contributions to lithium-ion batteries' development. The scientists who received the award are John B. Goodenough, M. Stanley Whittingham, and Akira Yoshino. The thing that led to their invention was the oil crisis that the world faced in the 197os, Whittingham used titanium disulfide and lithium metal as electrodes in the first attempt, but the combination had several challenges. However, Goodenough, an engineering professor at the University of Texas, came up with another fantastic idea, which was later improved by Akira Yoshino of Meijo University in Nagoya, Japan.

11-06 

Lithium battery protection panel wiring method

11-05 

How To Test Battery Life -Quality, Testing And Care

09-16 

What causes lithium battery to die?

09-11 

What are lipo battery BMS and PCB? Why are they needed for lithium battery?

BMS is battery management system, always for big battery packs, typical use is LiFePO4 power battery. It has protective functions of over charging, over discharging, over current, short-circuit, cells balancing functions, some battery may need also communication port and data input output options and other display functions. its up to applications requirements. PCB or PCM is protection circuit board, usually for small battery, typical use is for digital batteries, like mobile phone battery, camera battery,mp3 player battery, GPS batteries, heated clothing batteries and so on. Most time, Its for 3.7V or 7.4V battery, It has four basic functions of over charging, over discharging, short circuit, over current. some batteries may also need PTC and NTC. Anode of rechargeable lithium battery mostly is made of Lithium ion material, the Li electron goes to both anode and cathode sides once and once again during charging and discharging process, this how it works. In case of over charging,(lithium ion battery can not allow the cell voltage to be higher than 4.25v) the anode tiny hole structure may collapse, hard crystals substances may grow up and cause short circuit, then the temperature will rise up quickly, at last it will lead to a fire. So, over charging protection is needed. As for short circuit and over current, it’s easy to understand, because in these cases, the internal temperature will be higher and higher, and catch a fire in the battery. About over discharging, it’s also needs to be avoided, because lithium ion battery can lose large ratio of capacity forever once it was discharged to be too low level, for lithium ion battery cell, the voltage must be higher than 2.7V, if the voltage gets lower than this, eternal damage will happen to the battery. So at least PCB/PCM must be used for lithium ion battery with basic protections, however for bigger lithium battery packs, it involves lots of battery cells, the unbalance of cells will also cause problems, such as shorter cycle life, low voltage, so on base of above mentioned four protections, balance function is added to make a basic BMS.

07-17 

Basic knowledge of lithium battery

BasicknowledgeoflithiumbatteryInanideallithiumionbattery,apartfromtheinsertionandextractionoflithiumionsbetweenthepositiveandnegativeelectrodes,noothersidereactionsoccur,andnoirreversibleconsumptionoflithiumionsoccurs.Theactuallithium-ionbatteryhassidereactionsandirreversibleconsumptionatalltimes,suchaselectrolytedecomposition,activematerialdissolution,metallithiumdeposition,etc.,butthedegreeisdifferent.Inactualbatterysystems,anysidereactionthatcanproduceorconsumelithiumionsorelectronsineachcyclemaycausechangesinbatterycapacitybalance.Oncethebatterycapacitybalancechanges,thischangeisirreversible,andcanbeaccumulatedthroughmultiplecycles,whichwillhaveaseriousimpactonbatteryperformance.(1)DissolutionofcathodematerialThedissolutionofMninspinelLiMn2O4isthemainreasonforthereversiblecapacitydegradationofLiMn204.TherearegenerallytwoexplanationsforthedissolutionmechanismofMn:redoxmechanismandionexchangemechanism. TheredoxmechanismreferstothehighconcentrationofMn3+attheendofthedischarge.TheMn+onthesurfaceofLiMn2O4willundergoadisproportionationreaction:2Mn3+(solid)Mn4+(solid)+Mn2+(liquid)Thedivalentmanganeseionsgeneratedbythedisproportionationreactiondissolveintheelectrolyte.TheionexchangemechanismreferstotheexchangeofLi+andH+onthesurfaceofthespinel,ThefinalformationofHMn204withnoelectrochemicalactivity.Xiaetal.’sresearchshowedthatthecapacitylosscausedbythedissolutionofmanganeseaccountedforthepercentageofthetotalbatterycapacitylossthatincreasedsignificantlyasthetemperatureincreased(from23%atroomtemperatureto34%at55°C)[14].(2)Phasechangeofcathodematerial[15]Therearetwotypesofphasechangesinlithium-ionbatteries:-isthephasechangeoftheelectrodematerialwhenlithiumionsarenormallyreleased;theotheristhephasechangeoftheelectrodematerialwhenoverchargeoroverdischarge.Forthefirsttypeofphasetransition,itisgenerallybelievedthatthenormaldeintercalationreactionoflithiumionsisalwaysaccompaniedbychangesinthemolarvolumeofthehoststructure,andatthesametime,stressisgeneratedinthematerial,whichcauseschangesinthehostlattice,andthesechangesreducetheparticles.Electrochemicalcontactbetweenparticlesandelectrodes.ThesecondtypeofphasetransitionistheJahn-Tellereffect.TheJahn-Tellereffectreferstotheexpansionandcontractionofthestructurecausedbytherepeatedintercalationanddeintercalationoflithiumions,whichcausestheoxygenoctahedrontodeviatefromthesphericalsymmetryandbecomeadeformedoctahedralconfiguration.TheirreversibletransformationofthespinelstructurecausedbytheJahn-TellereffectisalsooneofthemainreasonsforthecapacitydegradationofLiMn204.Duringdeepdischarge,theaveragevalenceofMnislowerthan3.5V,andthestructureofspinelchangesfromcubicphasetotetragonalphase.Thetetragonalcrystalhaslowrelativesymmetryandstrongdisorder,whichreducesthereversibilityofthedeintercalationoflithiumions,whichismanifestedastheattenuationofthereversiblecapacityofthecathodematerial. (3)Reductionofelectrolyte[15] Electrolytescommonlyusedinlithiumionbatteriesmainlyincludesolventscomposedofamixtureofvariousorganiccarbonates(suchasPC,EC,DMC,DEC,etc.)andelectrolytescomposedoflithiumsalts(suchasLiPF6,LiCIO4,LiAsF6,etc.).Underchargingconditions,theelectrolyteisunstabletothecarbon-containingelectrode,soareductionreactionwilloccur.Electrolytereductionconsumestheelectrolyteanditssolvent,whichhasanegativeimpactonbatterycapacityandcyclelife.Theresultinggaswillincreasetheinternalpressureofthebatteryandthreatenthesafetyofthesystem.(4)Volumelosscausedbyovercharge[15]Depositionofnegativeelectrodelithium:Whenovercharged,lithiumionsaredepositedonthesurfaceofthenegativeelectrodeactivematerial.Thedepositionoflithiumions-ontheonehand.Thenumberofreversiblelithiumionsisreduced.Ontheotherhand,thedepositedlithiummetalcaneasilyreactwiththesolventorsaltmoleculesintheelectrolytetogenerateLi2CO3,LiForothersubstances,whichcanblocktheelectrodeHole,eventuallyleadingtolossofcapacityandlife.Electrolyteoxidation:Theelectrolytecommonlyusedinlithium-ionbatteriesiseasilydecomposedtoforminsolubleLi2CO3andotherproductswhenovercharged,blockingthepolarporesandgeneratinggas,whichwillalsocausethelossofcapacityandcausesafetyhazards.Oxygendefectinthepositiveelectrode:ThereisatendencytoloseoxygeninthepositiveelectrodeLiMn204inthehigh-voltageregion,whichcausesoxygendefectsandleadstocapacityloss.(5)Self-dischargeMostofthecapacitylosscausedbytheself-dischargeoflithium-ionbatteriesisreversible,andonlyasmallpartisirreversible.Themainreasonsforirreversibleself-dischargeare:thelossoflithiumions(theformationofinfallibleLi2CO3andothersubstances);theelectrolyteoxidationproductblockstheelectrodemicroporesandincreasestheinternalresistance. (6)FormationofinterfacefilmDuetotheirreversiblereactionbetweenlithiumionorelectrolyteandtheelectrode,szwillformasolidelectrolyteinterfacelayer(SEI)attheinterfacebetweenthenegativeelectrodeandtheelectrolyte.Thelossoflithiumionsduetotheformationofthispassivationfilmwillresultinachangeinthecapacitybalancebetweenthetwoelectrodes,andthecapacityofthebatterywilldecreaseinthefirstfewcycles.(7)CurrentcollectorThecur

07-17 

Basic knowledge of lithium battery

The composition of lithium batteries The lithium battery is mainly composed of two blocks, the battery cell and the protection board PCM (power battery-generally called the battery management system BMS). The battery cell is equivalent to the heart of the lithium battery, and the management system is equivalent to the brain of the lithium battery. The battery core is mainly composed of positive electrode material, negative electrode material, electrolyte, diaphragm and shell, while the protection board is mainly composed of protection chip (or management chip), MOS tube, resistor, capacitor and PCB board.

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