1 Lithium tsom xam thiab SEI zaj duab xis
Kab lus no tau txheeb xyuas cov txheej txheem ntawm lub peev xwm degradation hauv lithium-ion roj teeb, faib thiab teeb tsa cov yam ntxwv uas cuam tshuam rau kev laus thiab kev ua neej nyob ntawm lithium-ion roj teeb, thiab piav qhia ntau yam ntawm cov txheej txheem xws li overcharging, SEI zaj duab xis kev loj hlob thiab electrolyte, tus kheej tawm, active khoom poob, thiab tam sim no collector corrosion. Nws nthuav tawm cov kev tshawb fawb kev kawm ntawm cov kws tshawb fawb hauv ntau qhov chaw hauv cov roj teeb kev laus hauv xyoo tas los no, tshuaj xyuas kom meej txog cov kev cuam tshuam thiab cov qauv ntawm kev ua haujlwm ntawm lithium-ion roj teeb kev laus, thiab piav qhia txog cov qauv qauv ntawm kev laus sab kev xav.
Kev faib tawm thiab qhov cuam tshuam ntawm Kev Laus Ua Rau Lithium ion roj teeb
1. Kev faib tawm kev laus ua rau cov roj teeb lithium ion
Cov txheej txheem kev laus ntawm cov roj teeb lithium-ion yog cuam tshuam los ntawm ntau yam xws li lawv txoj kev sib koom ua ke hauv tsheb hluav taws xob, qhov kub thiab txias, tus nqi tawm, thiab qhov tob tob. Lub degradation ntawm lub peev xwm thiab kev ua tau zoo feem ntau yog tshwm sim los ntawm ntau cov txheej txheem tshuaj tiv thaiv, uas muaj feem xyuam rau ntau lub cev thiab tshuaj siv tshuaj. Lub degradation mechanism thiab aging daim ntawv yog heev complex. Nws qhia txog kev tsom xam mechanism ntawm lithium-ion roj teeb kev laus. Nyob rau hauv cov txheej txheem kev laus ntawm lithium-ion roj teeb, qhov sib txawv ntawm cov kev cuam tshuam los yog cov txheej txheem hloov pauv tshwm sim nyob rau hauv txhua feem ntawm lithium-ion roj teeb, thiab txhua tus txheej txheem muaj qhov sib txawv ntawm lub peev xwm degradation.
Raws li kev tshawb fawb tsis ntev los no ob qho tib si hauv tsev thiab txawv teb chaws, cov ntsiab lus tseem ceeb cuam tshuam rau lub peev xwm degradation mechanism ntawm lithium-ion roj teeb muaj xws li SEI zaj duab xis kev loj hlob, electrolyte decomposition, tus kheej tso tawm ntawm lithium-ion roj teeb, poob ntawm electrode active khoom, thiab corrosion ntawm tam sim no collectors. . Nyob rau hauv cov txheej txheem kev laus ntawm lithium-ion roj teeb, ntau yam kev tawm tsam tshwm sim ib txhij nrog cov tshuaj tiv thaiv electrode, thiab ntau yam kev laus ua haujlwm ua ke thiab ob leeg ua ke, ua rau muaj kev nyuaj ntawm kev kawm cov txheej txheem kev laus.
2. Kev laus los ntawm cov roj teeb lithium-ion
Kev laus ntawm lithium-ion roj teeb muaj qhov cuam tshuam loj heev rau lawv qhov kev ua tau zoo tag nrho, feem ntau tshwm sim hauv kev poob qis thiab kev ua haujlwm tawm, muaj peev xwm degradation, thiab thermal stability.
Cov yam ntxwv tseem ceeb ntawm cov roj teeb lithium-ion tom qab kev laus yog qhov txo qis hauv qhov muaj peev xwm thiab qhov nce hauv kev tiv thaiv sab hauv, uas ua rau txo qis ntawm cov nqi hluav taws xob thiab qhov muaj peev xwm tawm thiab qhov siab tshaj plaws muaj peev xwm thiab tawm lub zog ntawm lithium-ion roj teeb. ; Nyob rau tib lub sijhawm, vim qhov nce hauv kev tiv thaiv sab hauv ntawm lithium-ion roj teeb, muaj teeb meem xws li kev tsim hluav taws xob ntau ntxiv, kub nce hauv lub module, thiab nce qhov kub tsis sib xws thaum siv, uas yuav tsum muaj ntau dua rau kev tswj xyuas thermal ntawm roj teeb lithium-ion; Txawm li cas los xij, cov kev cuam tshuam sab hauv ntawm cov roj teeb lithium-ion sib txawv vim qhov sib txawv ntawm cov roj teeb pawg thiab cov qauv kev sib txuas, ua rau muaj qhov sib txawv ntawm kev siv tus kheej. Raws li lub roj teeb siv, qhov kev laus ntawm txhua tus neeg hauv lub roj teeb sib txawv, ua rau qhov tsis sib xws ntawm cov lithium-ion roj teeb pob.
Qhov qhib Circuit Court voltage nkhaus ntawm lithium-ion roj teeb characterizes lub tam sim no sab hauv electromotive quab yuam ntawm lithium-ion roj teeb. Raws li lub hnub nyoog lithium-ion roj teeb, qhov qhib Circuit Court voltage nkhaus yuav hloov los yog deform mus rau ib qho kev txheeb ze ntawm lub xeev qub, uas ua rau muaj kev hloov pauv ntawm cov nqi hluav taws xob thiab qhov hluav taws xob hluav taws xob ntawm lithium-ion roj teeb, uas cuam tshuam rau qhov tseeb ntawm lub xeev roj teeb. kev kwv yees nyob rau hauv lub roj teeb tswj system thaum siv tiag tiag. Nrog rau kev laus ntawm lithium-ion roj teeb, qhov siab tshaj plaws muaj nqi thiab tawm tus nqi ntawm lithium-ion roj teeb kuj tseem yuav txo. Yog tias lub roj teeb tswj tsis tau hloov kho, nws yooj yim ua rau overcharging, overdischarging, thiab high-power siv lithium-ion roj teeb, uas ua rau kom muaj kev nyab xeeb ntawm kev siv lithium-ion roj teeb.
Mechanism ntawm Peev Xwm poob hauv Lithium ion roj teeb
1. Kev soj ntsuam ntawm Kev Muaj Peev Xwm Tsis Txaus Siab tshwm sim los ntawm Lithium Precipitation
Daim duab qhia txog qhov poob ntawm cov lithium ions tshwm sim los ntawm lithium deposition los ntawm qhov tsis zoo electrode, uas yog hais txog cov txheej txheem ntawm lithium deposition los ntawm electrolyte mus rau electrode nto. Lub lithium deposition ntawm qhov tsis zoo electrode nto yog ib qho tseem ceeb ua rau kev laus hauv lithium-ion roj teeb thiab ib qho tseem ceeb cuam tshuam rau kev nyab xeeb ntawm roj teeb. Thaum qhov tsis zoo electrode muaj peev xwm tshaj qhov pib ntawm 0V ( txheeb ze rau Li / Li +), lithium deposition tshwm sim ntawm qhov tsis zoo electrode nto.
Lithium nag lossis daus tuaj yeem ua rau tsis tuaj yeem poob ntawm lithium ion cov khoom muag, ua rau muaj peev xwm txo qis. Kev loj hlob ntawm lithium dendrites ua rau poob ntawm lithium ions nquag, raws li qhia hauv daim duab. Muaj ntau yam uas cuam tshuam rau lithium deposition hauv roj teeb. Qee cov kws tshawb fawb ntseeg tias qhov qis qis qis ntawm lithium ions mus rau hauv graphite tsis zoo electrodes los yog hloov ceev ceev ntawm lithium ions mus rau qhov tsis zoo electrodes yuav ua rau lithium deposition.Tseem muaj cov kev tshawb fawb qhia tias qhov diffusion ntawm lithium ions qeeb qeeb thaum ua haujlwm nyob rau hauv qhov kub thiab txias, thiab qhov tsis zoo electrode ua haujlwm muaj peev xwm ze rau lithium deposition muaj peev xwm, ua rau nws yooj yim dua ua rau lithium deposition. Tsis tas li ntawd, ib qho me me N / P (qhov sib piv ntawm qhov tsis zoo electrode muaj peev xwm ua tau zoo electrode) tuaj yeem ua rau lithium deposition, thiab hauv zos electrode polarization thiab geometric mismatch kuj yuav ua rau lithium deposition.
Lithium evolution yog ze ze rau txoj kev laus. M ü hlbauer et al. ntseeg tias electrode lithium deposition feem ntau yuav tshwm sim nyob rau hauv cov roj teeb uas twb muaj lawm sab hauv tsis xws luag. Kabir thiab Demirocak pom tias lithium deposition tshwm sim nyob rau hauv cov roj teeb accelerates nyob rau hauv lub tom qab theem ntawm kev laus, dhau los ua ib qho ntawm cov laj thawj tseem ceeb rau qhov tshwm sim ntawm cov roj teeb muaj peev xwm inflection cov ntsiab lus. Yog vim li cas yog vim li cas raws li lub hnub nyoog roj teeb, SEI tiam ua rau ib tug txo nyob rau hauv lub porosity ntawm qhov tsis zoo electrode, thiab gradient ntawm electrolyte muaj peev xwm ntawm qhov tsis zoo electrode nce.Yog li ntawd, thaum lub sij hawm them tus txheej txheem, qhov tsis zoo electrode tej zaum yuav txo qis thiab feem ntau yuav poob qis dua 0V, ua rau lithium deposition; Cov txheej txheem lithium nag lossis daus tuaj yeem ua rau txo qis hauv qhov tsis zoo electrode porosity thiab nce hauv electrolyte muaj peev xwm gradient, ua rau cov roj teeb nrawm nrawm. Thaum lub roj teeb nyob hauv lub xeev tawm, lithium ntawm cov dendrites yuav yaj, tab sis cov khoom no tsis tuaj yeem tau txais cov khoom siv hluav taws xob vim tsis muaj kev sib cuag nrog cov khoom siv tam sim no, thiab tsis tuaj yeem koom nrog cov tshuaj tiv thaiv electrode thaum them thiab tawm, tsim cov lithium tuag. Lithium deposition ua rau poob ntawm active lithium ions raws li qhia hauv daim duab.
2. Qhov cuam tshuam ntawm SEI zaj duab xis loj hlob ntawm kev muaj peev xwm degradation
SEI zaj duab xis yog ib zaj duab xis passive tsim rau ntawm qhov tsis zoo electrode nto ntawm lithium-ion roj teeb, uas muaj ion conductivity thiab tiv thaiv electrons los ntawm, cais cov electrolyte los ntawm qhov tsis zoo electrode. SEI zaj duab xis loj hlob yog lub ntsiab lus ntawm cov roj teeb lithium-ion ntawm qhov tsis zoo electrode / electrolyte interface, uas tuaj yeem ua rau tsis muaj peev xwm poob. Lub roj teeb tus nqi, lub neej ntev, thiab cov yam ntxwv kev nyab xeeb yog ze ze rau SEI zaj duab xis; Raws li kev siv ib txwm siv, SEI zaj duab xis yog qhov tseem ceeb ua rau poob ntawm cov lithium hauv cov roj teeb.
SEI zaj duab xis yog tsim los ntawm inorganic tshuaj xws li Li2CO3, LiF, Li2O, nrog rau cov organic tshuaj xws li ROCO2Li, ROLi, RCOO2Li (qhov twg R yog ib pawg organic). Rau qee lub roj teeb, lub thickness ntawm SEI zaj duab xis tuaj yeem ncav cuag tshaj 100nm. Cov txheej txheem them thiab tso tawm ntawm cov roj teeb lithium-ion yog nrog los ntawm kev rov muab rho tawm thiab tso cov lithium ions ntawm qhov zoo thiab tsis zoo electrodes. Thaum lub sij hawm them nyiaj, cov khoom siv lithium ions nyob rau hauv cov khoom siv electrode zoo yuav dhau los ntawm cov khoom sib cais kom ncav cuag qhov tsis zoo electrode nto, dhau ib nrab ntawm tes cov tshuaj tiv thaiv, thiab tom qab ntawd muab tso rau hauv cov khoom tsis zoo electrode. Vim lub fact tias lub peev xwm ua hauj lwm ntawm qhov tsis zoo electrode nto ntawm lithium-ion roj teeb feem ntau yog qis dua lub thermodynamically ruaj khov lub qhov rais ntawm cov electrolyte, ib zaug lithium ions, electrolyte, thiab electrons ntawm qhov tsis zoo electrode nto tuaj rau hauv kev sib cuag, muaj yog muaj peev xwm txo tau cov electrolyte. Tsis tas li ntawd, muaj ntau yam kev cuam tshuam ntawm cov khoom nyob ze ntawm qhov tsis zoo electrode, uas ua rau tsim cov SE zaj duab xis ntawm qhov tsis zoo electrode nto, ua rau poob ntawm cov khoom siv hauv cov roj teeb lithium-ion, uas ua rau txo qis hauv qhov muaj peev xwm siab tshaj plaws thiab muaj peev xwm ua tau. nce impedance.
Kev tsim ntawm SEI zaj duab xis kuj yog ib qho ntawm cov laj thawj tseem ceeb rau daim ntawv qhia hnub nyoog laus nyob rau hauv qhov kub thiab txias (SOC) cov xwm txheej. Piv nrog cov roj teeb tshiab thiab SEI cov yeeb yaj kiab uas tsim los ntawm qhov kub thiab txias, SEI cov yeeb yaj kiab tsim los ntawm qhov kub siab dua muaj qhov zoo thermal stability thiab siab ceev dua li cov uas tsim los ntawm qhov kub thiab txias, uas tuaj yeem ua rau qeeb ntawm cov roj teeb. Txawm hais tias qhov kev loj hlob ntawm qhov tsis zoo SEI zaj duab xis yuav muaj kev cuam tshuam tsis zoo rau lub peev xwm thiab kev tiv thaiv sab hauv ntawm lithium-ion roj teeb, SEI zaj duab xis ruaj khov tuaj yeem txhim kho cov yam ntxwv ntawm cov khoom siv electrode thiab txhim kho cov roj teeb kev ua haujlwm. Qee cov kws tshawb fawb tseem ntseeg tias ob txheej txheej txheej txheej tsim los ntawm cov txheej txheem SEI (pib ua yeeb yaj kiab) thiab cov yeeb yaj kiab
Txawm hais tias muaj pes tsawg leeg ntawm SEI zaj duab xis tseem nyuaj rau kev txheeb xyuas kom raug, kev loj hlob, kev tawg, thiab kev tsim kho ntawm SEI zaj duab xis yog suav tias yog ze ze rau cov txheej txheem ntawm cov roj teeb muaj peev xwm degradation. SEI zaj duab xis yog tsim thaum pib tsim, thiab lub sijhawm no, SEI zaj duab xis yog xoob thiab ntxeem tau. Cov electrolyte infiltrates los ntawm lub qhov hws ntawm qhov chaw ntawm zaj duab xis thiab ua rau cov tshuaj tiv thaiv decomposition thaum sib cuag nrog cov electrode. Cov khoom ntim cov pores, ua rau SEI zaj duab xis ua ntom. Txawm li cas los xij, thaum lub sij hawm siv lub sij hawm ntev ntawm lub roj teeb, cov khoom siv hluav taws xob nws tus kheej kuj muaj qhov tshwm sim xws li kev nthuav dav thiab kev tawg, ua rau SEI hom ntawm qhov chaw dais kev ntxhov siab thiab ua thinner, uas ua rau kev loj hlob tsis tu ncua ntawm SEI zaj duab xis thaum lub sij hawm. lub voj voog. Txawm li cas los xij, SEI zaj duab xis kuj tuaj yeem raug puas tsuaj thaum lub sij hawm tso tawm sai, thaum lub sij hawm lub electrode ntim shrinks sai, ua rau SEI zaj duab xis rupture nyob rau hauv kev nyuaj siab, ua rau tsis ua hauj lwm ntawm SEI zaj duab xis. SEI zaj duab xis uas tau ruptured maj mam kho nws tus kheej thaum lub sij hawm tom ntej cycling txheej txheem. Txawm li cas los xij, kev tawg hauv cheeb tsam yuav ua rau tag nrho cov qauv ntawm SEI zaj duab xis tsis zoo, thiab qhov ceev tam sim no nyob ze ntawm qhov loj hlob yuav siab, tsim cov lus pom zoo kom nrawm rau kev loj hlob, tawg, thiab regrowth ntawm SEI zaj duab xis hauv qhov ntawd, ua rau kev laus tsis zoo nyob rau hauv cheeb tsam hauv cheeb tsam thiab maj mam ua rau tag nrho lub peev xwm poob ntawm lub roj teeb.
Tsim nyog tsim thev naus laus zis tuaj yeem txhim kho qhov ntom ntawm SEI zaj duab xis, yog li qeeb cov txheej txheem kev laus. Nyob rau tib lub sijhawm, qhov kub thiab txias ib puag ncig kuj yog qhov tsim nyog rau kev tsim cov yeeb yaj kiab SEI ntom ntom, yog li txhim kho cov kev pabcuam lub neej ntawm cov roj teeb.
2 Corrosion ntawm cov khoom siv tam sim no thiab poob ntawm cov khoom siv
Kab lus no tau txheeb xyuas cov txheej txheem ntawm lub peev xwm degradation hauv lithium-ion roj teeb, faib thiab teeb tsa cov yam ntxwv uas cuam tshuam rau kev laus thiab kev ua neej nyob ntawm lithium-ion roj teeb, thiab piav qhia ntau yam ntawm cov txheej txheem xws li overcharging, SEI zaj duab xis kev loj hlob thiab electrolyte, tus kheej tawm, active khoom poob, thiab tam sim no collector corrosion. Nws nthuav tawm cov kev tshawb fawb kev kawm ntawm cov kws tshawb fawb hauv ntau qhov chaw hauv cov roj teeb kev laus hauv xyoo tas los no, tshuaj xyuas kom meej txog cov kev cuam tshuam thiab cov qauv ntawm kev ua haujlwm ntawm lithium-ion roj teeb kev laus, thiab piav qhia txog cov qauv qauv ntawm kev laus sab kev xav.
Lub peev xwm poob los ntawm corrosion ntawm cov khoom siv tam sim no
Cov khoom siv tam sim no yog ib qho tseem ceeb hauv cov roj teeb lithium-ion, lub luag haujlwm nqa cov khoom siv, khaws thiab tso tawm. Cov khoom siv dav siv tam sim no yog tooj liab thiab txhuas: tooj liab yog nquag oxidation ntawm cov peev txheej siab thiab tsim nyog raws li cov khoom siv tam sim no rau cov khoom tsis zoo electrode xws li graphite thiab silicon; Vim nws qhov zoo ntawm tus nqi, txhua yam muaj zog, conductivity, thiab thermal conductivity, txhuas feem ntau suav hais tias yog ib qho ntawm cov khoom siv zoo tshaj plaws rau cov khoom siv hluav taws xob zoo electrode tam sim no.
Corrosion ntawm cov khoom siv tam sim no yuav txo tau lub neej ntawm lub roj teeb thiab cuam tshuam rau nws txoj kev ruaj ntseg thiab kev nyab xeeb. Nyob rau hauv kev ua haujlwm huab cua xws li tshaj tawm, xws li thaum qhov hluav taws xob poob mus rau 1.5V, tooj liab yuav raug oxidized rau hauv tooj liab ions hauv electrolyte, uas ua rau cov khoom tawg ntawm tooj liab tam sim no. Cov tooj liab ions oxidized los ntawm overdischarging yuav precipitate thiab tso rau ntawm qhov chaw ntawm cov khoom tsis zoo electrode nyob rau hauv daim ntawv ntawm hlau tooj liab thaum them nyiaj tom ntej. Cov tooj liab tso rau ntawm qhov chaw tsis zoo electrode yuav cuam tshuam qhov kev ntxig thiab tshem tawm ntawm lithium thiab ua rau thickening ntawm SEI zaj duab xis, uas ua rau muaj peev xwm degradation ntawm lithium-ion roj teeb.
Kev laus ntawm cov roj teeb uas tshwm sim los ntawm corrosion ntawm cov khoom siv tam sim no feem ntau yog tshwm sim los ntawm kev nce hauv kev ua haujlwm sab hauv. Cov txiaj ntsig tshawb fawb ntawm Xu Zhiyou et al. qhia tias cov roj teeb nrog aluminium ntawv ci raws li cov khoom siv tam sim no muaj qhov siab dua AC impedance, thiab lawv lub peev xwm ploj mus rau 10% ntawm tus nqi pib tom qab 350 cycles ntawm 10 degree C; Corroded aluminium ntawv ci tau pom tias muaj kev txhim kho tseem ceeb piv rau aluminium ntawv ci, tab sis nws qhov ruaj khov tseem tsis zoo. Tom qab 350 cycles ntawm 10 degree C, lub peev xwm lwj mus rau 22% ntawm tus nqi pib. Kev tshawb fawb los ntawm Song Wenji thiab lwm tus tau pom tias hauv electrolytes nrog lithium hexafluorophosphate ua cov electrolyte, ib qho me me ntawm cov dej tuaj yeem txhawb electrolyte decomposition thiab tsim cov ntsev inorganic ruaj khov, yog li inhibiting corrosion ntawm aluminium tam sim no collectors. Tab sis nrog rau tiam ntawm noo noo, oxidation decomposition khoom ntawm cov electrolyte undergo electrochemical tshua nyob rau saum npoo ntawm aluminium ntawv ci, ua rau thiab accelerating corrosion ntawm aluminium ntawv ci. Liu Xiao et al. txheeb xyuas qhov kev hloov pauv hauv cov tuab ntawm cov khoom siv tooj liab tam sim no thaum lub caij caij tsheb kauj vab uas siv cov tshuab luam ntawv electron microscopy. Cov txiaj ntsig tau pom tias cov tuab ntawm cov txheej ntxeem tau maj mam nce / qhov tuab ntawm cov khoom siv tam sim no poob qis. Thaum lub sij hawm electrochemical cycling txheej txheem, lub dissolution thiab tsim ntawm cov ntxeem tau txheej tshwm sim los ntawm corrosion ntawm tooj liab tam sim no collector ua rau ib tug tsis tu ncua txo nyob rau hauv lub thickness ntawm cov tooj liab tam sim no collector, ua rau ib tug nce nyob rau hauv lub internal kuj.
Lub peev xwm degradation tshwm sim los ntawm kev poob ntawm cov khoom siv hluav taws xob electrode
Thaum lub sij hawm them thiab tso tawm cov txheej txheem, lithium ions yuav embedded thiab deintercalated nyob rau hauv qhov zoo thiab tsis zoo electrodes, ua rau cov kev hloov nyob rau hauv lub ntim ntawm cov khoom electrode thiab tsim mechanical kev nyuaj siab. Thaum lub sij hawm tso tawm, cov khoom tsis zoo electrode undergoes ntim shrinkage vim lithium tshem tawm, thaum cov khoom zoo electrode undergoes ntim expansion vim lithium insertion. Thaum lub ntim shrinkage ntawm qhov tsis zoo electrode yog ntau dua qhov ntim expansion ntawm qhov zoo electrode, sab nraud kev ua tau zoo ntawm lub roj teeb yuav yog tag nrho ntim shrinkage, txwv tsis pub lub roj teeb yuav nthuav dav ntim; Thaum lub sij hawm them tus nqi siab, lub roj teeb yuav txuas ntxiv, thaum lub sij hawm them nqi qis, lub roj teeb yuav nthuav dav hauv lub ntim thaum lub sij hawm pib ntawm kev them nqi, kev cog lus thaum lub sij hawm nruab nrab ntawm kev them nqi, thiab nthuav dav dua nyob rau hauv cov theem tom ntej ntawm kev them nyiaj. Lub ntim hloov pauv ntawm graphite tsis zoo electrode nyob rau hauv kev them nqi thiab kev tso tawm tsis tshaj 10%, tab sis qhov kev ntxhov siab tsim los ntawm lub ntim hloov thaum lub sijhawm txheej txheem no tseem muaj peev xwm ua rau cov khoom tsis zoo electrode.
Cov khoom siv electrode zoo kuj raug deformation thaum lub sij hawm them thiab tawm, xws li muaj cov LiFePO4 thiab FePO4 theem hauv lithium hlau phosphate cov ntaub ntawv, nrog lub ntim hloov ntawm kwv yees li 6.81% thaum lub sij hawm them thiab tawm; Lub deformation ntawm LiMn2O4 thiab Mn2O4 thaum lub sij hawm them thiab tawm yog li 6.5%. Piv rau cov ntaub ntawv tsis zoo electrode, cov khoom siv electrode zoo cuam tshuam ntau dua los ntawm kev ntxhov siab. Kev tshawb fawb tau pom tias cov txheej txheem diffusion nce qhov concentration gradient ntawm lithium ions nyob rau hauv cov ntaub ntawv electrode, ua rau lub zos ntim expansion. Qhov kev nthuav dav tsis sib xws no ua rau muaj kev cuam tshuam kev ntxhov siab (DIS). Thaum lub diffusion induced kev nyuaj siab tshaj ib tug tej yam pib, particle breakage tej zaum yuav tshwm sim, thiab schematic daim duab ntawm zoo electrode cov ntaub ntawv poob yog qhia nyob rau hauv daim duab 5. Qhov no tshwm sim yog ntau pronounced thaum lub sij hawm ceev ceev thiab paug txheej txheem.
Lub thermal stress ntawm cov roj teeb feem ntau yog tshwm sim los ntawm qhov sib txawv ntawm qhov kub thiab txias. Shi Qitong indirectly characterizes qhov tshwm sim ntawm qhov kub thiab txias hloov nyob rau hauv kev ntxhov siab los ntawm kev hloov nyob rau hauv lub roj teeb thickness kev taw qhia, tab sis tsis soj ntsuam roj teeb puas los ntawm thermal stress. Lu Shigang et al. siv cov qauv kev simulation los txheeb xyuas qhov ntau yam cuam tshuam rau kev ntxhov siab thermal raws li cov ntaub ntawv faib tawm ntawm qhov ntsuas kub sab hauv thiab thermal stress field ntawm cov roj teeb square. Lawv pom tias qhov kub thiab txias yog siab tshaj ntawm qhov chaw geometric, thiab lub hauv paus cheeb tsam ntawm lub roj teeb tau raug kev nyuaj siab compression vim qhov kub-kub expansion, thaum lub lateral cheeb tsam tau raug tensile kev nyuaj siab; Nyob rau tib lub sij hawm, muaj ib tug tshwm sim ntawm concentrated thermal stress nyob rau hauv nruab nrab ntawm sab. Carlstedt thiab Asp tau txheeb xyuas qhov cuam tshuam ntawm qhov ntim thiab qhov kub thiab txias hloov ntawm kev ntxhov siab sab hauv thaum lub sij hawm them thiab tawm ntawm cov roj teeb cylindrical raws li diffusion induced stress los ntawm qhov sib txawv ntawm lithium ion concentration hauv cov khoom siv electrode thiab thermal stress generated los ntawm electrochemical cycling. Lawv ntseeg hais tias kev ntxhov siab muaj feem xyuam nrog cov kev txwv xws li kev them nyiaj thiab tso tawm cov nqi thiab qhov sib npaug. Ge et al. ntseeg hais tias electrodes ua los ntawm cov ntaub ntawv uas tsis zoo thermal expansion coefficients yuav zoo tshem tawm loj expansion thiab contraction tshwm sim los ntawm lithium ion insertion thiab extraction.
3 Electrolyte thiab diaphragm decomposition
Kab lus no tau txheeb xyuas cov txheej txheem ntawm lub peev xwm degradation hauv lithium-ion roj teeb, faib thiab teeb tsa cov yam ntxwv uas cuam tshuam rau kev laus thiab kev ua neej nyob ntawm lithium-ion roj teeb, thiab piav qhia ntau yam ntawm cov txheej txheem xws li overcharging, SEI zaj duab xis kev loj hlob thiab electrolyte, tus kheej tawm, active khoom poob, thiab tam sim no collector corrosion. Nws nthuav tawm cov kev tshawb fawb kev kawm ntawm cov kws tshawb fawb hauv ntau qhov chaw hauv cov roj teeb kev laus hauv xyoo tas los no, tshuaj xyuas kom meej txog cov kev cuam tshuam thiab cov qauv ntawm kev ua haujlwm ntawm lithium-ion roj teeb kev laus, thiab piav qhia txog cov qauv qauv ntawm kev laus sab kev xav.
Cov nyhuv ntawm electrolyte decomposition ntawm lub peev xwm degradation
Electrolyte yog ib qho ionic conductor uas tuaj yeem ua lithium ions ntawm qhov zoo thiab tsis zoo electrodes. Raws li tus naj npawb ntawm cov voj voog nce, cov electrolyte tau dhau los ua qee yam oxidation lossis decomposition tshwm sim nyob rau lub sijhawm, uas ua rau nws lub peev xwm hloov pauv huab cua tsis muaj zog thiab ua rau lub zog sab hauv ntawm lub roj teeb.
Ntxiv nrog rau qhov cuam tshuam nrog qhov zoo thiab qhov tsis zoo ntawm cov electrode ntawm lub roj teeb, cov electrolyte kuj tseem ua rau muaj kev cuam tshuam ntau hauv lithium deposition thiab cua sov; Nyob rau hauv cov cua kub, cov electrolyte yuav decompose thiab tsim gases xws li CO2, thiab ntxiv rau qhov kub thiab txias yuav ua rau combustion thiab tawg.
Kev tshawb fawb tau pom tias thaum qhov kev khiav hauj lwm voltage tshaj lub qhov rais electrochemical stability ntawm lub electrolyte, oxidative decomposition cov tshuaj tiv thaiv tshwm sim ntawm cov electrolyte thiab cov khoom zoo electrode. Kev tsim ntawm SEI zaj duab xis ntawm electrolyte thiab tsis zoo electrode, nrog rau cov txheej txheem tshuaj tiv thaiv ntawm electrolyte thaum lub sij hawm lithium evolution, feem ntau kawm ua ke nrog rau lwm yam kev laus. Cov kuab tshuaj organic hauv cov electrolyte tau txais ester pauv thiab cov tshuaj tiv thaiv polymerization thaum lub sijhawm ua haujlwm roj teeb, thiab cov ntsev ntsev xws li LiPF6 degrade hauv cov tshuaj tiv thaiv los tsim cov organic phosphates thiab fluorites. Henschel et al. txheeb xyuas qhov kev laus ntawm lithium-ion roj teeb electrolytes los ntawm tsib lub tuam txhab tsheb thiab pom tias thaum muaj hnub nyoog lithium-ion roj teeb, cov electrolyte nyob rau hauv ob lub zog thiab lub hwj chim roj teeb yuav muaj kev sib txawv ntawm qhov poob, thiab qhov concentration ntawm LiPF6 yuav txo qis.
Qhov cuam tshuam ntawm diaphragm decomposition ntawm lub peev xwm degradation
Lub separator yog cov khoom tseem ceeb rau cov roj teeb lithium-ion, uas tuaj yeem cais cov electrons. Thaum lub sij hawm them thiab tso tawm cov txheej txheem, lithium ions diffuse thiab propagate, lub cev sib cais qhov zoo thiab tsis zoo electrodes. Yog li ntawd, lub separator yog qhov tseem ceeb heev rau kev ua haujlwm nyab xeeb ntawm lub roj teeb. Yuav kom ua tau raws li qhov yuav tsum tau ua ntawm lithium-ion roj teeb, lub separator yuav tsum muaj cov tshuaj lom neeg ruaj khov, zoo wettability, zoo thermal stability, siab mechanical zog, thiab siab porosity. Lub siab porosity ntawm daim nyias nyias tuaj yeem ua tau raws li cov kev xav tau ntawm kev thauj mus los ion, thaum daim ntawv laus ntawm daim nyias nyias yog vim qhov txhaws ntawm daim nyias nyias pores, uas cuam tshuam ion thauj ntawm electrodes, ua rau lub zog attenuation thiab impedance nce.
Yog vim li cas rau daim nyias nyias los ntawm cov khoom decomposition ntawm electrolyte thiab blockage ntawm daim nyias nyias pores los ntawm active cov ntaub ntawv, uas yuav ua rau ib tug nce nyob rau hauv impedance thiab txo hwj chim muaj peev xwm. Cov laj thawj tseem ceeb rau kev laus ntawm daim nyias nyias tsis yog tsuas yog electrolyte yaig, lithium dendrites dhau los ntawm daim nyias nyias pores, thiab cov txheej txheem degradation los ntawm qhov kub thiab txias, tab sis kuj tsis sib xws ntawm cov khoom siv electrolyte decomposition ntawm daim nyias nyias, uas tuaj yeem ua rau txo qis hauv daim nyias nyias. ion conductivity. Wu et al. txheeb xyuas cov txheej txheem ntawm kev puas tsuaj ntawm daim nyias nyias thiab kev laus, thiab ntseeg tias lub ntsiab ua rau kev puas tsuaj ntawm daim nyias nyias yog tias dendrites tsim thaum lub sij hawm lithium evolution tuaj yeem tho cov yeeb yaj kiab nyias, ua rau txo qis hauv roj teeb lossis txawm tias luv luv. Kev hloov pauv asymmetric ntawm daim nyias nyias tuaj yeem cuam tshuam kev loj hlob ntawm lithium dendrites thiab txhim kho lub neej ntawm daim nyias nyias.
4 Kub + tus nqi tso tawm + overcharge
Kab lus no tau txheeb xyuas cov txheej txheem ntawm lub peev xwm degradation hauv lithium-ion roj teeb, faib thiab teeb tsa cov yam ntxwv uas cuam tshuam rau kev laus thiab kev ua neej nyob ntawm lithium-ion roj teeb, thiab piav qhia ntau yam ntawm cov txheej txheem xws li overcharging, SEI zaj duab xis kev loj hlob thiab electrolyte, tus kheej tawm, active khoom poob, thiab tam sim no collector corrosion. Nws nthuav tawm cov kev tshawb fawb kev kawm ntawm cov kws tshawb fawb hauv ntau qhov chaw hauv cov roj teeb kev laus hauv xyoo tas los no, tshuaj xyuas kom meej txog cov kev cuam tshuam thiab cov qauv ntawm kev ua haujlwm ntawm lithium-ion roj teeb kev laus, thiab piav qhia txog cov qauv qauv ntawm kev laus sab kev xav.
Qhov kub thiab txias ib puag ncig muaj kev cuam tshuam loj rau kev ua haujlwm, kev nyab xeeb, thiab lub neej ntev ntawm lithium-ion roj teeb. Qee cov kev tshawb fawb qhia tias cov roj teeb lithium-ion haum rau kev khiav hauj lwm hauv qhov kub thiab txias ntawm 15-35 degree . Hauv kev siv tswv yim, ntau yam kev tswj xyuas thermal feem ntau yog siv los tswj kev ua haujlwm kub ntawm lithium-ion roj teeb, yog li txuas ntxiv lawv lub neej voj voog thiab txhim kho kev nyab xeeb ntawm tag nrho cov roj teeb lub neej. Thaum qhov kub thiab txias, cov tshuaj tiv thaiv electrochemical qeeb qeeb, cov electrolyte conductivity txo, SEI zaj duab xis impedance nce, lithium ion hloov impedance nce, thiab polarization voltage nce nyob rau hauv kev them nyiaj thiab tso tawm. Yog li ntawd, lithium deposition yog nquag tshwm sim thaum lub sij hawm them nyiaj, uas ua rau irreversible txo nyob rau hauv lub roj teeb muaj peev xwm thiab txawm ua rau muaj kev nyab xeeb txaus ntshai.
Thaum ua hauj lwm ntawm qhov kub thiab txias, vim yog cov tshuaj tiv thaiv kinetics (Arrhenius effect), cov tshuaj tiv thaiv electrochemical ntawm lithium-ion roj teeb nce, lub zog sab hauv kuj txo, thiab lub peev xwm nce; Kev kub ceev tsis tu ncua yuav ua kom muaj kev cuam tshuam sab hauv hauv lub roj teeb, ua rau electrolyte oxidation thiab decomposition thiab txhawb kev tsim ntawm SEI zaj duab xis, uas ua rau irreversible peev xwm poob thiab impedance nce. Thaum lub sij hawm ua hauj lwm ntawm lithium-ion roj teeb, vim tsis tshua muaj thermal conductivity ntawm sab hauv Cheebtsam xws li electrodes thiab separators, kub gradients yog generated nyob rau hauv lub roj teeb hlwb. Qhov tshwm sim ntawm qhov kub thiab txias yog qhov tshwm sim ntau dua nyob rau hauv qhov chaw siab thiab qhov kub tsis tshua muaj, thiab qhov sib txawv ntawm qhov sib txawv ntawm qhov kub thiab txias no tuaj yeem ua rau qhov tsis sib xws ntawm qhov ntom ntom tam sim no, yog li ua kom lub roj teeb nrawm dua.
Tus nqi tso tawm
Tus nqi tam sim no tseem tuaj yeem ua rau txo qis ntawm lub peev xwm ntawm lithium-ion roj teeb. Qhov nce ntawm tus nqi tso tawm yuav ua rau kom muaj peev xwm lwj thiab qhov kev loj hlob ntawm ohmic tsis kam thiab polarization tsis kam ntawm cov roj teeb lithium-ion siab, nrog kev loj hlob ntawm polarization tsis kam yog siab dua li ntawm ohmic tsis kam. Qhov cuam tshuam ntawm tus nqi tso tawm ntawm lub roj teeb pob kev laus thiab qhov sib xws yog tshwm sim hauv kev ua kom cov laus ntawm ib lub hlwb nrog lub peev xwm me me. Rau cov roj teeb muaj peev xwm me me, nyob rau hauv cov nqi siab thiab tso tawm, overcharging thiab overdischarging phenomena tshwm sim ntau zaus, uas ua rau lub peev xwm lwj ntawm cov roj teeb me me thiab ua cov lus pom zoo. Qhov no tuaj yeem ua rau txo qis ntawm lub peev xwm muaj peev xwm ntawm lub pob roj teeb, thiab txawm tias muaj teeb meem kev nyab xeeb ntawm thermal vim muaj qhov tshwm sim xws li overcharging thiab tso tawm. Cov txheej txheem ntawm cov roj teeb aging tshwm sim los ntawm tus nqi siab thiab kev tawm mus yog feem ntau yog vim qhov tsis zoo ntawm cov khoom siv hluav taws xob zoo uas tshwm sim los ntawm kev cuam tshuam kev ntxhov siab uas tshwm sim thaum lub sij hawm tus nqi siab thiab tawm; Xav txog qhov txo qis hauv qhov ntim ntawm cov khoom siv hluav taws xob zoo electrode thaum lub sij hawm roj teeb, nws yuav ua rau muaj kev nce ntxiv hauv qhov ceev tam sim no ntawm ib cheeb tsam ntawm cov khoom siv electrode. Yog li ntawd, nyob rau hauv tus nqi siab tshaj tawm lub voj voog cov xwm txheej, roj teeb kev laus yuav nthuav tawm cov qauv nrawm.
Dubarry et al. tau ua cov kev sim kev laus ntawm cov roj teeb lithium-ion zoo sib xyaw siv ntau qhov kev them nqi thiab kev tso tawm, thiab cov txiaj ntsig tau pom tias cov nqi them siab thiab kev tso tawm yuav ua rau cov roj teeb ua haujlwm tsis zoo; Tom qab tshuaj xyuas cov txiaj ntsig degradation, nws ntseeg tau tias cov txheej txheem kev laus tuaj yeem muab faib ua ob theem. Lub peev xwm poob nyob rau hauv thawj theem yog los ntawm kev poob ntawm active lithium ions tshwm sim los ntawm kev tsim ntawm SEI zaj duab xis ntawm qhov tsis zoo electrode nto, thaum lub degradation nyob rau hauv lub thib ob theem yog los ntawm qhov poob ntawm electrode active khoom. Cheng et al. tau kawm txog cov yam ntxwv ntawm kev laus ntawm NCM lithium-ion roj teeb thiab pom tias muaj peev xwm poob nce nrog cov voj voog, nrog rau kev puas tsuaj rau cov khoom siv electrode zoo thiab tsim cov electrode tsis zoo SEI zaj duab xis thaum lub sij hawm kev laus. Barcellona thiab Piegari, los ntawm Peltier tiv thaiv qhov kub thiab txias hloov thaum lub sij hawm them nqi thiab tawm cov txheej txheem, ntseeg hais tias tsis muaj kev sib raug zoo tseem ceeb ntawm roj teeb kev laus thiab tus nqi tam sim no nyob rau hauv ib tug nqi tam sim no thiab tej yam kev mob SOC. Yang et al. tau tham txog kev sib raug zoo ntawm lub roj teeb kev ua tau zoo degradation thiab tus naj npawb ntawm cov voj voog uas siv cov qauv electrochemical thermal ua ke uas suav nrog kev cuam tshuam sab nraud. Lawv ntseeg hais tias raws li tus naj npawb ntawm cov voj voog tau nce, yuav muaj qhov hloov pauv hauv roj teeb kev laus, qhia txog kev hloov pauv ntawm kwv yees li linear mus rau nonlinear. Lub ntsiab yog vim li cas rau lub tom ntej nonlinear accelerated aging yog qhov tshwm sim ntawm lithium deposition ntawm qhov tsis zoo electrode nto.
Kev soj ntsuam ntawm qhov cuam tshuam ntawm overcharging ntawm lub peev xwm degradation
Lub peev xwm degradation ntawm cov roj teeb uas tshwm sim los ntawm overcharging feem ntau suav nrog lithium deposition vim tsis zoo electrode overcharging, roj ntau lawm vim zoo electrode overcharging, thiab intensified sab tshwm sim thaum electrolyte overcharging.
Thaum qhov tsis zoo electrode yog overcharged, lithium evolution cov tshuaj tiv thaiv tshwm sim, ua rau lub deposition ntawm metallic lithium, uas yog feem ntau yuav tshwm sim thaum muaj ib tug ntau tshaj ntawm zoo electrode active khoom piv rau tsis zoo electrode active khoom. Txawm li cas los xij, nyob rau hauv cov ntaub ntawv ntawm kev them nqi siab, txawm tias qhov piv ntawm cov khoom siv hluav taws xob zoo thiab tsis zoo yog qhov qub, lithium evolution tseem tuaj yeem tshwm sim. Kev tso tawm ntawm cov roj ntsha lithium tuaj yeem ua rau muaj peev xwm degradation hauv cov roj teeb los ntawm cov hauv qab no: ① ua rau txo qis ntawm cov lithium rov qab hauv lub roj teeb; ② Lub precipitated metallic lithium undergoes sab kev cuam tshuam nrog cov kuab tshuaj los yog electrolytes, tsim lwm yam by-products thiab noj cov electrolyte, uas ua rau ib tug txo nyob rau hauv paug efficiency; ③ Lithium hlau feem ntau tso ntawm qhov tsis zoo electrode thiab cov khoom sib cais, uas tuaj yeem ua rau muaj kev cuam tshuam ntawm qhov sib cais ntawm qhov pores thiab ua rau muaj kev tiv thaiv sab hauv ntawm lub roj teeb.
Thaum qhov sib piv ntawm cov khoom siv hluav taws xob zoo rau cov khoom siv hluav taws xob tsis zoo rau cov khoom siv hluav taws xob tsawg dhau, qhov zoo electrode overcharging yog qhov tshwm sim. Qhov zoo electrode overcharging feem ntau ua rau muaj peev xwm degradation ntawm cov roj teeb los ntawm kev tsim cov tshuaj electrochemical inert, oxygen poob, thiab lwm yam ntaub ntawv. Vim muaj kev cuam tshuam ntawm lub peev xwm sib npaug ntawm cov electrodes, irreversible poob ntawm roj teeb muaj peev xwm tshwm sim. Nyob rau tib lub sijhawm, cov pa oxygen tso tawm los ntawm cov tshuaj tiv thaiv electrode kuj tseem tuaj yeem ua rau muaj kev nyab xeeb rau kev siv cov roj teeb lithium-ion.
Yog hais tias lub charger voltage ntawm lithium-ion roj teeb yog siab dhau lawm, nws yuav ua rau oxidation tshwm sim nyob rau hauv lub electrolyte thiab tsim insoluble tshuaj (xws li Li2CO3) thiab gases. Cov khoom los ntawm cov khoom no yuav thaiv cov electrode micropores, cuam tshuam kev tsiv teb tsaws ntawm lithium ions, thiab ua rau txo qis hauv kev caij tsheb kauj vab. Ntxiv mus, raws li cov electrolyte tau noj, nws cov huab hwm coj hloov pauv tsis muaj zog, ua rau muaj kev nce ntxiv hauv cov roj teeb sab hauv. Tsis tas li ntawd, yog tias cov khoom lag luam tsim tawm, ib zaj duab xis passivation tuaj yeem tsim rau ntawm qhov chaw electrode, uas yuav ua rau cov roj teeb polarization thiab txo cov zis voltage ntawm lub roj teeb.
5 Roj teeb tsis sib xws + txoj kev them nqi + qhov tob ntawm kev them nqi thiab tawm
Kab lus no tau txheeb xyuas cov txheej txheem ntawm lub peev xwm degradation hauv lithium-ion roj teeb, faib thiab teeb tsa cov yam ntxwv uas cuam tshuam rau kev laus thiab kev ua neej nyob ntawm lithium-ion roj teeb, thiab piav qhia ntau yam ntawm cov txheej txheem xws li overcharging, SEI zaj duab xis kev loj hlob thiab electrolyte, tus kheej tawm, active khoom poob, thiab tam sim no collector corrosion. Nws nthuav tawm cov kev tshawb fawb kev kawm ntawm cov kws tshawb fawb hauv ntau qhov chaw hauv cov roj teeb kev laus hauv xyoo tas los no, tshuaj xyuas kom meej txog cov kev cuam tshuam thiab cov qauv ntawm kev ua haujlwm ntawm lithium-ion roj teeb kev laus, thiab piav qhia txog cov qauv qauv ntawm kev laus sab kev xav.
Internal inconsistency ntawm roj teeb
Yuav kom ua tau raws li lub zog thiab lub zog xav tau ntawm tag nrho lub tsheb, cov roj teeb lithium-ion feem ntau yuav tsum tau txuas nrog hauv cov koob lossis sib npaug ua ntej lawv tuaj yeem siv rau hauv lub tsheb fais fab. Vim qhov sib txawv ntawm cov txheej txheem tsim khoom, kev ua haujlwm ib puag ncig, thiab lwm yam kev mob, lub hlwb tuaj yeem pom qhov txawv ntawm qhov muaj peev xwm, impedance, txiav tawm voltage, thiab lwm yam ntxwv. Qhov kev tsis sib haum no tuaj yeem ua rau muaj kev laus zuj zus ntawm cov roj teeb pob nyob rau hauv lub tsheb ua haujlwm nyuaj, yog li cuam tshuam rau kev ua haujlwm ntev, kev cia siab, thiab kev nyab xeeb ntawm lub tsheb hluav taws xob.
Qhov tsis sib xws ntawm cov roj teeb feem ntau yog tshwm sim los ntawm qhov sib txawv me me ntawm cov txheej txheem tsim khoom thiab cov khoom siv ntawm lub Hoobkas, nrog rau qhov sib txawv ntawm qhov chaw siv thaum lub sijhawm siv roj teeb tom ntej. Inconsistencies feem ntau yog tshwm sim nyob rau hauv tsis xws li roj teeb voltage, internal kuj, thiab muaj peev xwm. Qhov cuam tshuam ntawm qhov tsis sib xws ntawm qhov tsis sib xws ntawm kev ua neej nyob feem ntau yog tshwm sim thaum kawg ntawm kev tso tawm. Cells nrog qis voltage yuav ncav cuag qhov kev txiav tawm voltage ua ntej thiab ncav cuag lub xeev khoob, thaum lwm cov roj teeb muaj qhov hluav taws xob ntau dua li qhov txiav tawm hluav taws xob thiab tseem muaj qee lub peev xwm sab hauv. Kev tso tawm ntawm cov roj teeb ntawm SOC qis muaj qhov cuam tshuam loj rau lawv lub neej, yog li ntawd, qhov kev laus ntawm cov hlwb uas tsis muaj tag nrho yuav nrawm dua li lwm cov roj teeb.
Kev tshawb fawb tau pom tias muaj kev sib raug zoo ntawm qhov tsis sib xws ntawm lithium-ion roj teeb modules / systems thiab inconsistency ntawm lithium-ion roj teeb hlwb. Feem ntau, lub neej kev pab cuam ntawm lub pob roj teeb tsawg dua li qhov kev pab cuam lub neej ntawm cov roj teeb qis tshaj plaws hauv pob roj teeb. Vim qhov tsis sib xws ntawm kev siv cov lithium-ion roj teeb pob, qhov peev xwm tiag tiag ntawm txhua tus neeg ntawm tes sib txawv. Yog li ntawd, nyob rau hauv tib lub load tam sim no tej yam kev mob, qhov tseeb qhov tob ntawm tus nqi thiab tawm ntawm txhua lub cell kuj txawv. Cov khoom siv roj teeb uas siv rau hauv cov dej ntws sib sib zog nqus rau lub sijhawm ntev muaj lub neej luv dua li cov uas siv nyob rau hauv qhov dej ntiav ntiav; Them thiab tso tawm lub zog tshaj qhov zoo tshaj plaws them thiab tawm tam sim no tuaj yeem cuam tshuam rau lub neej kev pab cuam ntawm lub roj teeb pob. Ziberman et al. tau kawm txog cov yam ntxwv ntawm kev laus ntawm cov khoom siv lithium-ion roj teeb uas siv cov txheej txheem sib txawv ntawm qhov sib txawv ua ke nrog kev siv tshuab electron microscopy. Cov txiaj ntsig tau pom tias qhov ntsuas kub ntawm 5 degree yuav ua rau muaj qhov sib txawv ntawm cov roj teeb kev laus, uas ua rau muaj peev xwm degradation thiab kev ua haujlwm poob ntawm lub roj teeb pob.
Daim ntawv them nqi thiab lub tswv yim
Cov txheej txheem them nyiaj ntawm lithium-ion roj teeb muaj qhov cuam tshuam loj rau lub peev xwm degradation ntawm lithium-ion roj teeb. Cov txiaj ntsig kev tshawb fawb qhia tau hais tias kev them nyiaj txiav tawm hluav taws xob ntawm lithium-ion roj teeb muaj qhov cuam tshuam loj rau cov txheej txheem kev laus. Siv lub lithium manganese oxide system lithium-ion roj teeb ua piv txwv, piv txwv li nws qhov kev them nyiaj txiav tawm yog 4V, me ntsis txo qhov kev txiav tawm hluav taws xob tuaj yeem txhim kho lub neej muaj nyob. Tab sis nws muaj peev xwm kuj yuav txo tau raws li. Cov cuab yeej no tuaj yeem muab kev taw qhia rau kev tsim cov tswv yim them ceev ceev rau cov roj teeb lithium-ion. Ntawm qhov tod tes, them ceev ceev ntawm lithium-ion roj teeb kuj tseem muaj feem cuam tshuam rau kev laus. Cov txiaj ntsig kev tshawb fawb qhia tau hais tias kev laus nyob rau hauv kev them nyiaj ceev mus rau 100% yog qhov pom tau zoo dua piv rau cov laus hauv kev them nyiaj sai mus rau 80%, thiab txawm tias kev laus nyob rau hauv ib txwm them rau 100% yog qhov hnyav dua piv rau cov laus hauv qab them ceev rau 80%.
Pulse tso tawm tuaj yeem txhim kho kev them nqi thiab txo lub sijhawm them nqi piv rau classical tsis tu ncua tam sim no (CC) them lossis qhov tsis tu ncua tam sim no tsis tu ncua (CC-CV) txoj kev them nyiaj. Cov txiaj ntsig kev tshawb fawb qhia tau hais tias kev them nyiaj pulse tuaj yeem txo lub sijhawm them nyiaj ntau, tab sis ua kom cov mem tes zaus tsis ua kom zoo dua qub thaum siv tib txoj kev them nyiaj pulse. Txawm li cas los xij, pulse charging muaj qhov cuam tshuam loj rau kev laus roj teeb. Cov txiaj ntsig kev sim ntawm Li et al. qhia tau hais tias qhov kev tiv thaiv sab hauv ntawm lithium-ion roj teeb tau nce ntxiv nyob rau hauv cov xwm txheej ntawm lub plawv dhia, thiab kev tsom xam raws li kev ntsuas hluav taws xob hauv tshuab hluav taws xob pom pom qhov poob loj ntawm cov khoom siv hluav taws xob tsis zoo.
Qhov tob ntawm kev them nqi thiab tso tawm
Cov txiaj ntsig kev tshawb fawb qhia tau hais tias thaum lub sijhawm them thiab tso tawm ntawm cov roj teeb lithium-ion, kev sib sib zog nqus thiab kev tso tawm yuav ua rau lub peev xwm degradation ntawm lithium-ion roj teeb, thiab lub sijhawm no, ohmic kuj thiab polarization tsis kam ntawm lithium-ion roj teeb yuav ob qho tib si. nce; Ntawm qhov tod tes, nyob rau hauv tib qhov tob ntawm kev them nqi thiab kev tso tawm, cov roj teeb lithium-ion cycled nyob rau hauv qhov siab SOC ntau yam muaj kev laus dua piv rau cov cycled hauv qhov qis SOC, uas tej zaum yuav yog vim muaj teeb meem ntawm lithium deposition hauv. High SOC ntau yam. Tsis tas li ntawd, thaum lub sij hawm ceev lub voj voog kev laus ntawm cov roj teeb lithium-ion, qhov kev laus ntawm cov nqi them tam sim no yog siab dua li qhov tam sim no thiab qhov hluav taws xob tsis tu ncua. Yog li ntawd, ncua sij hawm tsis ua hauj lwm thaum lub sij hawm them thiab tawm los yog siv tsis tshua muaj nqi tam sim no thaum kawg ntawm kev them nyiaj yog qhov zoo rau kev ua kom lub roj teeb lub neej ntev.