Cov roj teeb lithium ion tsis tshua "tsim" lub zog raws li cov neeg feem coob xav txog nws. Lawv ua dab tsi yog khaws cov hluav taws xob hluav taws xob los ntawm kev hloov pauv hluav taws xob hluav taws xob, tom qab ntawd tso tawm thaum cov hluav taws xob sab nraud xav tau tam sim no. Qhov tsis meej pem txog qhov no tshwm sim ntau hauv cov rooj sib tham tsim, tshwj xeeb tshaj yog thaum ib tus neeg sim ua kom loj lub roj teeb rau thawj zaug.
Ob yam tshwm sim thaum tso tawm. Ua ntej, lithium ions migrate los ntawm qhov tsis zoo electrode (anode) los ntawm electrolyte thiab separator mus rau qhov zoo electrode (cathode). Thib ob, electrons ntws los ntawm sab nraud Circuit Court los ntawm anode mus rau cathode, ua haujlwm tseem ceeb. Thaum lub sij hawm them nyiaj, koj thim rov qab cov txheej txheem los ntawm kev siv ib qho hluav taws xob sab nraud uas quab yuam ions thiab electrons txav mus rau qhov sib txawv.
Qhov hluav taws xob ntawm lub xov tooj ntawm tes tsim yog nyob ntawm cov khoom siv hluav taws xob uas koj xaiv thiab lawv cov peev txheej electrochemical. Lub cell tshiab zaum ntawm lub txee uas tsis muaj load yuav qhia tau tias nws qhib - Circuit Court voltage- feem ntau nyob ib ncig ntawm 3.6 txog 3.7V rau feem ntau lithium ion chemistry, txawm tias tus lej no txav mus los nyob ntawm lub xeev tus nqi thiab qhov kub thiab txias. Thaum koj txuas lub load thiab pib kos tam sim no, qhov hluav taws xob poob vim muaj kev tiv thaiv sab hauv. Nws poob ntau npaum li cas qhia koj ntau txog kev noj qab haus huv ntawm tes.
Cell Chemistry Fundamentals
Txhua lub hlwb lithium ion qhia tib lub hauv paus kev khiav hauj lwm, tab sis chemistry sib txawv. Cov khoom siv cathode feem ntau txiav txim siab lub xov tooj ntawm tes cov yam ntxwv ua haujlwm - zog ceev, lub zog muaj peev xwm, lub neej voj voog, thermal stability, thiab nqi.
Txheej oxide cathodes yog thawj coj mus muag chemistry. Sony tau tshaj tawm lawv rov qab rau xyoo 1991 nrog LiCoO₂ (lithium cobalt oxide), uas tseem siv rau hauv cov khoom siv hluav taws xob uas muaj zog ntom ntom ntau dua li cov nqi lossis kev nyab xeeb. Cov hlwb no ntim kwv yees li 150-200 Wh / kg ntawm qib cell. Cobalt tseem kim heev, thiab chemistry tau tsis ruaj khov saum 150 degree. Peb tau pom thermal runaway pib ntawm qhov kub tsawg li 130℃hauv cov hlwb raug tsim txom.
Kev tsav tsheb kom muaj kev nyab xeeb zoo dua thiab tus nqi qis ua rau LiMn₂O₄ (lithium manganese oxide) nyob rau nruab nrab -1990s. Manganese yog av pheej yig thiab cov qauv spinel yog qhov ruaj khov dua. Cov hlwb no yuav tsis khiav mus txog thaum koj dhau 250℃feem ntau. Kev sib pauv? Lub zog ceev poob mus rau 100-120 Wh / kg, thiab manganese yaj mus rau hauv cov electrolyte dhau sijhawm, tshwj xeeb tshaj yog nyob rau qhov kub siab. Lub voj voog lub neej raug kev txom nyem-koj tab tom saib tej zaum 300-700 lub voj voog ua ntej lub peev xwm poob qis dua 80%.
LiFePO₄ (lithium hlau phosphate) tshwm sim nyob ib ncig ntawm 2001 thiab hloov kev sib tham txog kev nyab xeeb. Cov qauv olivine yog pob zeb-cov khoom thermally; thermal runaway tsis tshwm sim kom txog thaum siab dua 270 degree, thiab txawm tias tom qab ntawd nws tsis nruj heev. Lub neej voj voog yog qhov zoo tshaj-2,000+ mus rau 80% muaj peev xwm yog tus qauv, thiab qee lub hlwb tau sim dhau 5,000 lub voj voog. Lub downside yog voltage: tsuas yog 3.2V nominal, thiab lub zog ceev yog txwv rau 90-120 Wh / kg. Tsis tas li ntawd, qhov xwm txheej phosphate patent tau ntxhov rau ntau xyoo.
NMC (lithium nickel manganese cobalt oxide) thiab NCA (lithium nickel cobalt aluminium oxide) tau tshwm sim raws li "balanced" chemistry. Los ntawm kev sib xyaw npib tsib xee, manganese, thiab cobalt nyob rau hauv ntau qhov sib piv -cov khoom siv feem ntau yog NMC 111, 532, 622, thiab 811 qhov twg cov lej qhia txog cov ntsiab lus hlau txheeb ze - koj tuaj yeem kho qhov kev ua tau zoo. Cov ntsiab lus nickel siab dua thawb lub zog ceev mus rau 200-250 Wh / kg tab sis ntawm tus nqi ntawm thermal stability thiab lub neej voj voog. NMC 811 hlwb tuaj yeem ntaus 250 Wh / kg tab sis xav tau kev tswj xyuas thermal ntau dua.
Nyob rau sab anode, graphite tau tus qauv txij li hnub ib. Lub peev xwm theoretical yog 372 mAh / g, thiab cov hlwb ua lag luam feem ntau ua tiav 340-360 mAh / g. Cov lithium intercalates ntawm graphene txheej thaum them nyiaj, nthuav cov graphite ntim li ntawm 10%. Qhov kev ntxhov siab ntawm txhua yam no ua rau muaj peev xwm ploj mus dhau kev caij tsheb kauj vab.
Silicon anodes tau "qhov loj tom ntej" rau txog kaum tsib xyoos tam sim no. Silicon lub peev xwm theoretical yog 4,200 mAh / g-ntau tshaj kaum npaug graphite. Teeb meem yog, silicon expands los ntawm 300% thaum nws absorbs lithium. Qhov no rhuav tshem cov anode sib nrug tom qab ob peb lub voj voog. Cov txheej txheem tam sim no siv silicon-graphite sib xyaw nrog cov ntsiab lus silicon feem ntau qis dua 10% kom tswj tau qhov nthuav dav. Txawm li ntawd los, thawj zaug - lub voj voog irreversible peev poob khiav 15-25% hauv silicon-muaj anodes piv rau 5-10% rau cov graphite ntshiab.
Cell Tsim thiab Hom
Cylindrical cells yog tej zaum cov neeg feem coob pom thaum lawv xav tias "roj teeb." Hom 18650 (18mm txoj kab uas hla, 65mm ntev) tau dhau los ua txhua yam tom qab cov tuam txhab lag luam laptop tsim qauv rau nws thaum xyoo 2000s. Tesla nto moo siv ntau txhiab ntawm lawv nyob rau hauv thawj Roadster. Hom 18650 muaj peev xwm khiav 2,000-3,500 mAh nyob ntawm chemistry thiab seb koj ua kom zoo rau lub zog lossis lub zog.
Qhov tshiab 21700 hom (21mm × 70mm) uas Tesla thiab Panasonic koom ua ke tsim muaj txog 50% ntau zog rau ib lub xov tooj ntawm tes-4,000-5,000 mAh tam sim no. Txoj kab uas hla loj nce qhov sib piv ntawm cov khoom siv rau cov khoom siv tsis muaj zog (cov khoom siv tam sim no, tuaj yeem, cov khoom siv kev nyab xeeb), kev txhim kho lub zog ntom ntom ntawm cov pob. Cov kab tsim khoom yuav tsum tau rov ua dua, uas yog ib feem ntawm vim li cas kev saws me nyuam yuav siv sij hawm ntev.
Prismatic hlwb tau los ntawm kev lag luam automotive lub siab xav siv qhov chaw zoo dua. Es tsis txhob sau ib lub thawv nrog lub tog raj kheej thiab tawm hauv txhua qhov chaw tsis muaj dab tsi, koj ua cov duab plaub uas ua haujlwm zoo. Automotive -qib prismatic hlwb muaj li ntawm 20Ah mus rau ntau tshaj 100Ah muaj peev xwm. Lawv yooj yim dua rau kev ua kom sov- tswj hwm los ntawm qhov chaw ntim khoom vim tias koj tuaj yeem tso cov phiaj xwm txias ncaj qha rau sab hauv. Qhov downside yog koj tau txais tag nrho koj cov qe hauv cov pob tawb tsawg dua -yog tias ib lub xov tooj loj prismatic tsis ua haujlwm, koj poob peev ntau dua yog tias ib lub xov tooj me me cylindrical tsis ua haujlwm.
Lub hnab ntim khoom siv lub tswv yim ntawm qhov chaw ua haujlwm ntxiv los ntawm kev tshem tawm cov hlau tuaj yeem ua tiav. Lub xovtooj tau muab ntim rau hauv ib lub hnab uas hloov tau yooj yim aluminium-laminate hnab. Qhov no txuag tej zaum 10-15% qhov hnyav piv rau lub prismatic tuaj yeem, thiab cov hom yog hloov tau yooj yim heev-koj tuaj yeem ua rau lawv qhov loj me lossis cov duab uas yuav tsum tau ua. EV cov tuam txhab nyiam lawv vim tias koj tuaj yeem tso lawv ncaj qha rau hauv cov phiaj xwm txias. Qhov tsis muaj zog yog cov neeg kho tshuab: lawv xav tau sab nraud compression los tiv thaiv electrode delamination thaum caij tsheb kauj vab, thiab lawv yooj yim dua rau kev puas tsuaj.
Separator Technology
Lub separator tsis tau txais kev saib xyuas ntau, tab sis nws yog qhov tseem ceeb tshaj plaws ntawm kev nyab xeeb. Nws yog nyias nyias (16-25 μm feem ntau) ntxeem tau daim nyias nyias uas ua rau cov anode thiab cathode tsis txhob kov thaum tso cai rau lithium ions hla dhau. Cov cais thaum ntxov yog ib txheej polyethylene (PE) lossis polypropylene (PP).
Niaj hnub nimno siab -kev ua tau zoo sib cais siv cov qauv trilayer, feem ntau PP / PE / PP. PE txheej muaj qhov qis qis (135 degree) dua li PP (165 degree). Yog hais tias lub cell pib overheating, PE melts thiab nyob rau hauv lub qhov hws, kaw ionic thauj ua ntej kub mus txog theem txaus ntshai. Qhov no yog hu ua thermal shutdown, thiab nws yog koj txoj kab kawg ntawm kev tiv thaiv ua ntej thermal runaway.
Ceramic-coated separators ntxiv lwm qhov kev nyab xeeb. Ib tug nyias (2-4 μm) txheej ntawm alumina los yog lwm yam ceramic hais ntawm ib los yog ob sab ntawm lub separator tswj kev ncaj ncees txawm tias cov polymer melts. Cov txheej yog ntxeem tau txaus uas ionic thauj mus ntxiv, tab sis nws tiv thaiv cov electrode los ntawm luv luv -circuiting txawm nyob rau ntawm qhov kub siab tshaj 150℃. Qhov downside yog tus nqi -ceramic-coated separators khiav 2-3 × tus nqi ntawm tus qauv cais-thiab me ntsis siab dua impedance.
Porosity feem ntau khiav 40-50%. Tsawg dhau thiab ionic tsis kam nce, txwv lub zog muaj peev xwm. Siab dhau lawm thiab mechanical zog raug kev txom nyem. Pore loj faib tseem ceeb heev; Gurley tooj (air permeability test) yog tus qauv spec. Feem ntau EV-qib cais lub hom phiaj 200-400 vib nas this / 100cc.
Electrolyte Composition thiab Additives
Cov electrolyte nyob rau hauv ib lub lithium ion cell yog complex tshaj li koj xav. Lub hauv paus formulation feem ntau yog lithium ntsev-LiPF₆ (lithium hexafluorophosphate) nyob rau hauv 95%+ ntawm cov cell-kua nyob rau hauv ib tug sib tov ntawm organic carbonates. Cov kuab tshuaj muaj xws li ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), thiab ethyl methyl carbonate (EMC).
LiPF₆ concentration feem ntau yog nyob ib ncig ntawm 1.0 txog 1.2 M (molar). Cov concentration siab dua txhim kho ionic conductivity mus txog qhov taw tes, tab sis dhau 1.3 M lossis yog li koj pib tau ntsev los nag ntawm qhov kub thiab txias. LiPF₆ muaj teeb meem- nws ya raws- rhiab heev thiab pib decomposing saum 60℃-tab sis lwm txoj kev xws li LiBOB lossis LiFSI tseem tsis tau hloov nws vim yog tus nqi lossis lwm yam kev lag luam.
Cov kuab tshuaj carbonate sib xyaw tau raug kho rau daim ntawv thov. EC muaj siab dielectric tas li thiab zoo SEI- tsim cov khoom, tab sis nws khov ntawm 36℃. Koj yuav tsum tau muab nws nrog qis dua - viscosity carbonates zoo li DMC lossis EMC kom tswj tau qhov ntsuas kub qis dua -. Ib qho kev tsim qauv yuav yog EC: DMC 1: 1 los ntawm ntim, lossis EC: EMC 3: 7. Cov piv txwv tseeb yog tus tswv thiab saib xyuas zoo.
Additives yog qhov tseeb chemistry khawv koob tshwm sim. Niaj hnub nimno electrolytes muaj 2-5% los ntawm qhov hnyav ntawm ntau yam additives uas hloov SEI tsim, tiv thaiv overcharge, suppress roj tsim, los yog txhim kho siab - kub stability. Vinylene carbonate (VC) ntawm 1-2% yog ze li ntawm universal rau kev txhim kho SEI zoo ntawm graphite anodes. Fluoroethylene carbonate (FEC) ua haujlwm zoo dua rau silicon-muaj anodes. Cov tebchaw no nyiam txo qis thaum pib lub voj voog, tsim cov txheej txheem tiv thaiv ntawm cov anode uas yog ionically conductive tab sis hluav taws xob insulating.
Overcharge tiv thaiv additives zoo li biphenyl los yog cyclohexylbenzene pib polymerizing nyob ib ncig ntawm 4.5V, tsim ib tug sab hauv shunt uas tiv thaiv voltage los ntawm nce ntxiv. Qhov no muab qee qhov kev tiv thaiv rau koj yog tias BMS ua tsis tiav, txawm tias kev cia siab rau nws tsis yog qhov kev coj ua zoo tshaj plaws.
Khoom Electrolyte Interface Tsim
SEI yog tej zaum qhov kev nkag siab tsawg tshaj plaws tab sis tseem ceeb tshaj plaws ntawm lithium ion roj teeb ua haujlwm. Thaum thawj ob peb lub voj voog, cov khoom siv electrolyte hnov mob nrog lub anode nto, tsim ib txheej passivation. Cov txheej no yog qhov tseem ceeb: nws yuav tsum yog ionically conductive (kom tso cai rau lithium ions los ntawm) tab sis hluav taws xob insulating (kom tiv thaiv electrolyte decomposition ntxiv). SEI muaj pes tsawg leeg yog ib qho mess-ntaus lithium ntsev, organic compounds, thiab polymers tag nrho sib xyaw ua ke hauv ib txheej 10-100 nm tuab.
Kev tsim SEI zoo yog qhov sib txawv ntawm lub xov tooj ntawm tes uas mus txog 500 zaug thiab ib qho uas mus txog 3,000 zaug. Qhov teeb meem yog tias SEI tsis zoo li qub. Nws tawg thaum lub ntim hloov pauv hauv anode, nthuav tawm qhov chaw tshiab uas siv cov electrolyte thiab lithium ntau dua los kho qhov kev puas tsuaj. Qhov no yog vim li cas lub peev xwm ploj mus dhau kev caij tsheb kauj vab txawm tias koj maj mam nrog lub xov tooj ntawm tes.
Kev tsim lub voj voog yog ib kauj ruam tseem ceeb ntawm kev tsim khoom. Cov xovtooj tau txais ib lossis ntau dua tus nqi qeeb- tso tawm cov voj voog ntawm qhov ntsuas kub los tsim qhov pib SEI. Cov txheej txheem tsim tawm yog tus tswv, tab sis thawj zaug - cov nqi them nqi yog C / 20 txog C / 10, thiab cov txheej txheem tuaj yeem siv sijhawm 24-48 teev. Cov neeg tsim khoom ua kom zoo tshaj qhov tsim hluav taws xob txwv, qhov kub thiab txias, lub sijhawm so, thiab cov qauv kev caij tsheb kauj vab los tsim SEI ruaj khov tshaj plaws. Tau txais qhov tsis raug no raug nqi koj lub neej voj voog.
Calendar aging -tsis muaj peev xwm txawm tias thaum lub xov tooj tsuas yog zaum ntawm - feem ntau yog qhov tshwm sim SEI ib yam nkaus. Lub SEI tseem loj hlob qeeb ntawm qhib Circuit Court, siv cyclable lithium. Cia nyob rau hauv lub xeev siab ntawm tus nqi thiab kub siab accelerates qhov no. Ib lub cell khaws cia ntawm 100% SOC thiab 60℃yuav poob 20% peev hauv ib xyoos, thaum tib lub xov tooj ntawm 50% SOC thiab 25℃yuav poob 3%.
Charging Protocols thiab Battery Management
Cov roj ntsha lithium ion muaj kev cuam tshuam rau kev tshaj tawm, tshaj - tso tawm, thiab them nyiaj ntawm qhov kub tsis tsim nyog. Qhov no yog vim li cas txhua lub xov tooj ntawm tes ntau - pob roj teeb xav tau BMS (lub roj teeb tswj lub cev).
Tus txheej txheem them nqi yog qhov tam sim no / qhov hluav taws xob tsis tu ncua (CC-CV). Thaum lub sijhawm CC, koj thawb tam sim no mus rau hauv lub xovtooj ntawm tus nqi ruaj khov -feem ntau 0.5C txog 1C rau feem ntau cov hlwb, txawm tias qee qhov siab - lub zog hluav taws xob tuaj yeem tswj tau 3C lossis ntau dua. Voltage nce raws li cov nqi ntawm tes. Thaum qhov hluav taws xob nce mus txog qhov txwv siab (4.2V rau feem ntau chemistry, 3.65V rau LFP, 4.3V lossis 4.35V rau qee qhov siab - zog NMC variants), koj hloov mus rau CV hom. Tam sim no tapers tawm thaum lub xovtooj mus txog tag nrho cov nqi, feem ntau txiav tawm thaum tam sim no poob qis dua C / 20 lossis C / 50.
Kev them nyiaj ceev yog qhov nyuaj dua. Cov nqi them ntau dua ua kom cov lithium plating ntawm lub anode, uas yog qhov txaus ntshai -hlau lithium yog qhov muaj zog heev thiab tuaj yeem ua rau lub cev luv lossis dendrite tsim uas nkag mus rau hauv cov khoom sib cais. Txhawm rau kom ceev - them nyiaj kom nyab xeeb, koj yuav tsum nkag siab tias qhov voltage, tam sim no, thiab qhov kub thiab txias cuam tshuam lithium plating li cas.
Qhov teeb meem yog tias koj tsis tuaj yeem ntsuas lithium plating ncaj qha rau hauv lub cell kaw. Koj yuav tsum infer nws los ntawm lwm cov cim. Ib txoj hauv kev yog taug qab anode muaj peev xwm tiv thaiv lithium hlau siv. Yog tias muaj peev xwm anode mus qis dua 0V piv rau Li / Li⁺, plating yog tshwm sim. Qhov teeb meem yog, feem ntau cov lag luam hlwb tsis muaj cov khoom siv electrodes.
Kub nce thaum lub sij hawm them ceev kuj tseem ceeb. Lub xov tooj ntawm tes them ntawm 2C tuaj yeem pom nws qhov kub thiab txias sab hauv 15-20℃saum toj ib puag ncig txawm tias muaj cua txias. Thaum txias txias, qhov no yeej pab tau -lub xov tooj cua txias (hais -10 degree) muaj lub zog tsis zoo, tab sis yog tias koj tuaj yeem sov nws los ntawm kev them nqi nruab nrab (0.5C), kev ua tau zoo dua. Qee cov EVs yeej ua qhov no rau lub hom phiaj: thaum huab cua txias, lawv yuav khiav lub sijhawm luv luv ntawm cov nqi tam sim no kom sov lub roj teeb ua ntej tus neeg tsav tsheb xav tau lub zog siab rau kev nrawm.
Cell ntsuas yog tsim nyog vim hais tias cov cell hauv series yeej tsis nyob twj ywm zoo kawg nkaus match. Kev tsim cov kev kam rau siab, qhov sib txawv me me ntawm tus kheej - tus nqi tawm, thiab cov thermal gradients thoob plaws pob ua rau muaj hluav taws xob drift. Yog tias koj them ib txoj hlua tsis muaj qhov sib npaug, qee lub hlwb ntaus lub siab voltage txwv ua ntej lwm tus. Cov hlwb muaj zog yog undercharged, lub hlwb tsis muaj zog yog overcharged, thiab kev ua tau zoo raug kev txom nyem.
Passive ntsuas siv cov resistors los ntshav tawm lub zog los ntawm siab dua -voltage cells. Nws yog ib qho yooj yim thiab pheej yig tab sis nkim zog raws li cua sov. Kev ntsuas ntsuas siv DC-DC converters lossis capacitors kom hloov lub zog ntawm cov hlwb siab mus rau cov hlwb qis. Ntau npaum, ntau complex, kim dua. Rau ib pob 400V EV, qhov ntsuas qhov ntsuas tsis tu ncua yuav nkim 50-100W tsis tu ncua, uas yog qhov tsis txaus ntseeg piv rau kev tsav tsheb tab sis ntxiv rau lub sijhawm.
Thermal Management Considerations
Thaum tshav kub kub nyob rau hauv lub lithium ion cell los ntawm peb qhov chaw: irreversible cua sov (Joule cua sov los ntawm lub sab hauv kuj), reversible cua sov (entropy hloov ntawm cov tshuaj tiv thaiv electrochemical), thiab tshav kub los ntawm sab tshua. Ntawm qhov qis mus rau nruab nrab C- tus nqi, thim rov qab cua sov dominates. Thaum siab C- tus nqi, irreversible heats over.
Lub sij hawm rov qab ua kom sov yog qhov nthuav vim nws hloov pauv kos npe nyob ntawm SOC. Rau feem ntau lithium ion chemistry, them nyiaj ua kom sov ntawm SOC tsawg tab sis absorbs cua sov ntawm siab SOC. Discharge ua qhov opposite. Qhov crossover point yog nyob ib ncig ntawm 50-60% SOC feem ntau. Qhov no yog vim li cas koj thiaj tuaj yeem pom qhov ntsuas kub ntawm tes tau poob thaum lub sijhawm kawg ntawm kev them nyiaj yog tias tam sim no qis txaus.
Internal kuj txawv nrog kub, SOC, thiab laus. Ntawm 25 degree, 18650 cell tshiab yuav muaj 40-60 milliohms DC tsis kam. Ntawm -20 degree, uas tuaj yeem dhia mus rau 200-300 milliohms. Qhov no yog vim li cas huab cua txias EV ntau poob qis heev. Tsis tsuas yog chemistry qeeb qeeb ntawm qhov kub thiab txias, tab sis qhov kev tiv thaiv sab hauv nce txhais tau tias ntau dua ntawm lub roj teeb lub zog yog nkim thaum tshav kub hauv lub cell.
Lub thermal runaway pib nyob ntawm chemistry. Rau NMC hlwb, exothermic decomposition tshwm sim pib ntawm 180-220 degree. Thaum pib, kub tuaj yeem nce ntawm 10-50℃ib ob, ncav cuag 800℃lossis siab dua. LFP muaj kev nyab xeeb ntau dua; thermal runaway pib yog 270℃+ thiab qhov siab tshaj plaws mus txog yog qis dua.
Kev nthuav tawm ntawm cov hlwb hauv ib pob yog qhov txaus ntshai tiag tiag. Yog hais tias ib lub cell nkag mus rau hauv thermal khiav, nws heats nws cov neeg nyob ze. Txawm hais tias cov hlwb nyob sib ze kuj khiav tawm yog nyob ntawm qhov muaj peev xwm ua kom txias, qhov sib nrug ntawm tes, thiab rwb thaiv tsev. UL 9540A propagation testing simulates qhov no los ntawm kev yuam ib lub xovtooj mus rau hauv thermal khiav thiab saib xyuas seb cov cell uas nyob ib sab ua raws. Kev tsim pob zoo muaj qhov tsis ua haujlwm rau ib lub xovtooj lossis feem ntau ntawm ib qho me me.
Cov tswv yim txias sib txawv. Cua txias yog qhov yooj yim tshaj plaws - tshuab cua hla lub hlwb lossis pob. Ua haujlwm OK rau cov ntawv siv hluav taws xob tsawg xws li PHEVs lossis lub zog cia. Ua kua txias yog tsim nyog rau siab -kev ua tau zoo EVs. Feem ntau cov qauv siv 50:50 dej-glycol sib tov ntawm 10-25 litres ib feeb los ntawm cov phaj txias lossis cov cua txias. Inlet kub yog feem ntau tswj rau 20-35 degree. Lub roj teeb pob kub gradients yuav tsum nyob qis dua 5℃max rau min kom tsis txhob muaj kev laus zuj zus ntawm cov hlwb kub tshaj plaws.
Qee qhov kev sim tsim siv cov tub yees txias, immersion txias hauv dielectric kua, los yog theem- hloov cov ntaub ntawv. Cov tub yees txias tuaj yeem rub tawm cov cua sov ntau dua tab sis yuav tsum muaj lub zog AC ntau dua. Immersion cooling muaj cov coefficients hloov pauv tau zoo heev (500-2,000 W / m²K piv rau 50-150 W / m²K rau cov kua dej tsis ncaj) tab sis kev sib khi thiab cov kua dej sib xws yog qhov nyuaj. PCMs ua haujlwm tsis tu ncua tab sis yuav tsum tsis lees txais cov cua sov thaum kawg, yog li lawv feem ntau pab ua kom txias txias thaum lub sijhawm them ceev lossis nrawm nrawm.
Kev ua haujlwm tsis zoo thiab tsis ua haujlwm hom
Lub peev xwm ploj mus thiab kev loj hlob impedance yog ob lub ntsiab degradation mechanisms. Lawv tshwm sim los ntawm ntau qhov sib txawv ntawm lub cev thiab cov txheej txheem tshuaj lom neeg tshwm sim ib txhij.
Nyob rau sab anode, SEI kev loj hlob siv cyclable lithium thiab electrolyte, ua rau muaj zog. Graphite exfoliation tuaj yeem tshwm sim yog tias lub xov tooj ntawm tes raug them ntawm qhov kub qis - lithium daim hlau ntawm cov graphite nto es tsis txhob intercalating, thiab thaum nws ua tiav intercalate, nws tawg cov qauv graphite sib nrug. Qhov no feem ntau irreversible. Binder decomposition ntawm qhov kub siab ua rau poob ntawm hluav taws xob sib cuag ntawm cov khoom.
Cathode degradation suav nrog kev hloov pauv hlau tawg (tshwj xeeb tshaj yog manganese hauv LMO lossis manganese-muaj NMC), cov qauv hloov pauv los ntawm kev rov ua cov lithium ntxiv / rho tawm, thiab kev tsim kho saum npoo hauv siab -nickel cathodes. Cov yaj hloov pauv hlau tsiv mus rau anode qhov chaw uas lawv catalyze SEI kev loj hlob, yog li cathode degradation indirectly accelerates anode degradation.
Electrolyte decomposition thiab roj tsim yog cov teeb meem loj ntawm cov hluav taws xob siab thiab kub siab. Cov pa roj carbon ntau muaj xws li CO₂, CO, thiab ntau yam hydrocarbons los ntawm carbonate decomposition. Nyob rau hauv lub hnab hnab, koj yuav pom lub hnab o visibly. Hauv cylindrical lossis prismatic hlwb nrog cov teeb meem nyuaj, lub siab ua kom txog thaum lub qhov cua qhib (feem ntau ntawm 10-15 bar).
Kev poob ntawm lithium cov khoom muag yog ib qho tseem ceeb ntawm kev ploj. Txhua lub sij hawm SEI loj hlob los yog lithium daim hlau irreversibly ntawm lub anode, ib co lithium raug tshem tawm ntawm lub pas dej ua ke ntawm cyclable lithium. Thaum kawg koj khiav tawm thiab muaj peev xwm poob.
Sudden tsis ua hauj lwm tuaj yeem tshwm sim los ntawm cov luv luv. Cov luv luv feem ntau pib me me -ib cov hlau me me punctures lub separator, los yog lithium dendrite loj tuaj. Qhov luv luv tsim qhov chaw kub, uas ua rau kom muaj kev puas tsuaj hauv zos, uas ua rau luv luv, thiab koj tau txais cov lus pom zoo. Qee zaum lub xovtooj ntawm tus kheej- kho yog tias qhov luv melts nws tus kheej qhib. Lwm lub sij hawm nws nce mus rau thermal runaway.
Kev ntsuam xyuas cov ntsia hlau (yuav tsum tau ntsia hlau ntsia hlau los ntawm lub xov tooj ntawm tes) yog ib qho kev ntsuas kev tsim txom. LFP hlwb feem ntau tsis nkag mus rau hauv thermal khiav tawm ntawm tus ntsia thawv nkag. NMC hlwb feem ntau ua, tab sis cov qauv tsim nrog cov khoom sib cais zoo dua thiab qis zog tshwj xeeb tuaj yeem dhau los.
Daim duab 5 daim phiaj muaj peev xwm tuav tau piv rau lub voj voog tus lej rau ntau cov chemistry nyob rau hauv nruab nrab kev caij tsheb kauj vab (1C nqi / tso tawm, 25℃, 100% DOD).
State of Charge thiab State of Health Estimation
Koj tsis tuaj yeem ntsuas ncaj qha tias muaj zog npaum li cas hauv lub lithium ion cell. Koj yuav tsum kwv yees nws los ntawm lwm yam kev ntsuas: voltage, tam sim no, thiab kub.
Txoj kev kwv yees SOC yooj yim tshaj plaws yog voltage-raws li. Txhua chemistry muaj tus yam ntxwv qhib - Circuit Court voltage piv rau SOC nkhaus. Ntsuas qhov hluav taws xob tom qab lub xov tooj ntawm tes tau so ib pliag (kom cia qhov hluav taws xob hloov pauv los ntawm kev tiv thaiv sab hauv), saib nws ntawm OCV nkhaus, thiab koj paub SOC. Teeb meem yog, koj tsis tshua muaj sij hawm rau lub cell so nyob rau hauv tiag tiag daim ntaub ntawv.
Kev suav suav Coulomb yog txoj hauv kev. Koj koom ua ke tam sim no dhau sijhawm los taug qab cov nqi hauv thiab tawm. Yog tias koj pib ntawm SOC paub, koj tuaj yeem suav SOC tshiab txhua lub sijhawm. Qhov tseeb nyob ntawm koj qhov ntsuas tam sim no (± 0.5% yog qhov raug) thiab paub txog qhov muaj peev xwm tiag tiag. Kev ua yuam kev sib sau ua ke dhau sijhawm, yog li koj yuav tsum tau rov ua kom rov qab ua ntu zus los ntawm kev ua kom tiav tag nrho lossis lub voj voog tawm.
Qauv-raws li txoj hauv kev siv cov qauv sib npaug lossis cov qauv hluav taws xob ntawm lub xov tooj ntawm tes. Koj ntsuas lub davhlau ya nyob twg voltage thiab tam sim no, khiav lawv los ntawm koj tus qauv, thiab rho tawm cov xeev sab hauv suav nrog SOC. Extended Kalman lim los yog cov neeg soj ntsuam hauv xeev zoo sib xws. Cov txheej txheem no tuaj yeem ua tau zoo heev (± 2% SOC yuam kev) tab sis xav tau cov qauv zoo thiab cov khoom siv suav nrog tseem ceeb.
Kev kwv yees SOH nyuaj dua vim tias koj tab tom sim ntsuas qhov degradation, uas qeeb thiab maj mam. Kev muaj peev xwm ploj mus thiab kev loj hlob impedance tsis tas yuav sib cuam tshuam nrog ib leeg lossis nrog lub voj voog suav. Lub xovtooj ntawm tes uas tau ceev ceev-them ntau yuav muaj impedance siab tab sis tsuas muaj peev xwm ploj mus xwb. Ib lub xovtooj ntawm tes uas tau khaws cia ntawm qhov siab SOC / qhov kub thiab txias yuav muaj peev xwm ploj mus tab sis qhov kev loj hlob ntawm impedance kuj tsis tshua muaj.
Kev lag luam xyaum yog los txhais SOH raws li lub peev xwm: ib lub xovtooj ntawm 80% ntawm nws cov peev txheej qub yog nyob ntawm 80% SOH, thiab qhov no feem ntau suav tias yog kawg - ntawm - lub neej rau EV daim ntawv thov. Lub cell tseem ua haujlwm, tab sis ntau yam tau poob 20%. Rau kev siv lub zog cia, cov hlwb yuav raug siv mus rau 60-70% SOH.
Qee qhov BMSs ua lub sijhawm kuaj xyuas lub peev xwm- tso tawm lub roj teeb tag nrho ntawm tus nqi qis thiab ntsuas seb lub zog tawm los npaum li cas. Qhov no yog qhov tseeb tab sis cuam tshuam (lub roj teeb tsis muaj thaum lub sijhawm kuaj) thiab siv sijhawm ntau teev. Lwm txoj hauv kev sim kwv yees lub peev xwm ncaj qha los ntawm qhov hluav taws xob nkhaus, ntsuas impedance, lossis coulombic efficiency.
Kev tiv thaiv sab hauv tuaj yeem ntsuas tau los ntawm kev siv cov mem tes tam sim no thiab ntsuas qhov ntsuas hluav taws xob, lossis los ntawm kev txhaj tshuaj AC me me ntawm ntau zaus (electrochemical impedance spectroscopy). EIS muab cov ntaub ntawv ntau ntxiv tab sis xav tau cov khoom siv tshwj xeeb uas tsis tshua muaj nyob rau hauv kev lag luam BMSs.
Thib ob -Kev siv lub neej thiab kev rov ua dua tshiab
Thaum lub roj teeb EV mus txog qhov kawg - ntawm- lub neej (feem ntau yog 70-80% ntawm lub peev xwm qub), nws tseem ua haujlwm zoo rau cov ntawv thov tsawg dua. Kev siv roj teeb lub neej thib ob tau txais traction rau lub zog ruaj khov.
Kev lag luam yog qhov nyuaj. Koj yuav tsum sim cov pob nyiaj so haujlwm, muaj peev xwm rov tsim kho nws (hloov BMS, lub kaw lus txias, lossis cov qauv puas), lees paub nws rau daim ntawv thov tshiab, thiab muab kev lees paub. Tag nrho cov no raug nqi nyiaj. Rau qhov thib ob - lub neej kom muaj kev nkag siab, cov pob khoom kho tshiab yuav tsum raug nqi tsawg dua li lub pob tshiab tsim los rau daim ntawv thov nyob ruaj khov. Cov nqi tawg txawm tias kev kho dua tshiab khiav qis dua 40-50% ntawm tus nqi tshiab pob, nyob ntawm seb nws qhov kev tshuaj xyuas koj ntseeg.
Kev ntsuam xyuas cov cell so haujlwm tsis yog- tsis tseem ceeb. Ib lub module yuav muaj ntau pua lub hlwb hauv series -parallel. Koj tsis tuaj yeem sim lawv tus kheej yooj yim. Koj tuaj yeem sim cov module ua ib chav, tab sis ib lub xovtooj tsis zoo tuaj yeem npog nws tus kheej. Qee hom kev degradation yog ib qho nyuaj rau kev kuaj xyuas yam tsis muaj kev puas tsuaj. Kuj tseem muaj cov lus nug txog kev lav phib xaub: yog tias lub thib ob - roj teeb lub neej hluav taws kub, leej twg yog tus lav?
Kev rov ua dua tshiab yog qhov kawg kawg - ntawm - txoj kev ua neej. Tam sim no loj - nplai recycling siv pyrometallurgy (smelting) los yog hydrometallurgy (chemical leaching). Pyrometallurgy yog qhov yooj yim dua tab sis xaiv tsawg dua -koj tau txais cov hlau sib xyaw uas xav tau kev kho kom zoo ntxiv. Hydrometallurgy tuaj yeem rov qab tau cov hlau ntawm ib tus neeg ntawm purity siab dua tab sis yuav tsum muaj ntau kauj ruam thiab tsim cov tshuaj khib nyiab.
Kev lag luam ntawm kev rov ua dua tshiab nyob ntawm cov nqi hlau ntau heev. Cobalt muaj txiaj ntsig (kwv yees li $ 30-40 / kg keeb kwm, txawm tias tus nqi hloov pauv tsis zoo), yog li kev rov ua dua cobalt- nplua nuj chemistry yog kev lag luam. Nickel yog tsim nyog rov ua dua ntawm qhov ntsuas. Manganese, hlau, thiab txhuas yog tsawg- cov hlau muaj txiaj ntsig, yog li kev rov ua dua tshiab ua rau kev txiav txim siab kom lawv tawm ntawm qhov chaw pov tseg. Lithium yog qhov nthuav - nws tsis yog tshwj xeeb tshaj yog muaj txiaj ntsig rau ib kilogram, tab sis kev txwv kev txwv ua rau rov qab zoo nkauj.
Direct recycling-disassembling lub roj teeb thiab rov siv cov khoom siv cathode lossis anode ncaj qha yam tsis tau rhuav tshem cov ntsev hlau- yog thaj chaw tshawb fawb kub. Yog tias koj tuaj yeem rov qab cathode hmoov hauv daim ntawv siv tau, koj yuav txuag lub zog thiab tus nqi ntawm cathode synthesis. Cov kev sib tw suav nrog kev sib cais cov khoom siv los ntawm cov khoom siv tam sim no thiab cov khoom sib khi, thiab kev soj ntsuam nrog qhov tseeb tias cov khoom siv rov ua dua tshiab yog kev sib xyaw ntawm cov hlwb los ntawm cov tuam txhab sib txawv, hnub nyoog, thiab chemistry.
