Lithium Ion Battery Mfiridwuma ho mfitiasesɛm

Lithium ion battery "nnya" ahoɔden ankasa wɔ ɔkwan a nnipa dodow no ara susuw ho no so. Nea wɔyɛ ne sɛ wɔkora anyinam ahoɔden so denam anyinam ahoɔden a wotumi dannan so, afei wogyae bere a abɔnten so amansin no hwehwɛ ahoɔden no. Adwene mu naayɛ a ɛfa eyi ho no ba pii wɔ adwini nhyiam ahorow ase, titiriw bere a obi rebɔ mmɔden sɛ ɔbɛma batere kɛse ayɛ nea edi kan no.

Nneɛma abien sisi bere a wɔayi obi afi ayaresabea hɔ no. Nea edi kan no, lithium ions tu fi electrode a enye (anode) no mu fa electrolyte ne separator no mu kɔ electrode a ɛyɛ papa (cathode) no mu. Nea ɛto so abien no, ɛlɛtrɔnik fa abɔnten so kwan no mu fi anode so kɔ cathode so, na ɛyɛ adwuma a mfaso wɔ so. Bere a worebɔ charge no, wodan adeyɛ no denam abɔnten so ahoɔden bi a ɛhyɛ ions ne electron ma ɛkɔ ɔkwan a ɛne no bɔ abira so a wode bedi dwuma no so.

Voltage a cell bi de ba no gyina electrode nneɛma a wobɛpaw ne wɔn electrochemical tumi ahorow so koraa. Cell foforo a ɛte shelf a enni adesoa biara bɛkyerɛ ne open-circuit voltage-a mpɛn pii no bɛyɛ 3.6 kosi 3.7V ma lithium ion nnuru dodow no ara, ɛwom sɛ saa dodow yi di akɔneaba gyina charge ne ɔhyew tebea so. Sɛ woka adesoa bi bom na wufi ase twe current a, voltage no so tew esiane emu resistance nti. Sɛnea ɛso tew no ma wuhu nkwammoaa no akwahosan ho nsɛm pii.

Lithium Ion Battery Technology

Lithium ion nkwammoaa nyinaa wɔ nnyinasosɛm titiriw koro a wɔde yɛ adwuma, nanso ɛsono nnuruyɛ kɛse. Cathode ade no titiriw na ɛkyerɛ nkwammoaa no adwumayɛ su-ahoɔden a ɛyɛ den, tumi a ɛtumi yɛ, kyinhyia nkwa, ɔhyew a ɛgyina pintinn, ne ɛka.

Layered oxide cathodes ne nnuru a edi kan a wɔde dii gua. Sony de wɔn bae wɔ 1991 mu tɔnn denam LiCoO2 (lithium cobalt oxide) so, a wɔda so ara de di dwuma wɔ ɛlɛtrɔnik mfiri a wɔde di dwuma mu wɔ baabi a ahoɔden dodow ho hia sen ɛka anaa ahobammɔ ho mfaso. Saa nkwammoaa yi pack bɛyɛ 150-200 Wh/kg wɔ nkwammoaa no mu. Nanso Cobalt bo yɛ den, na nnuru no ntumi nnyina boro digrii 150 . Yɛahu sɛ ɔhyew mu guankɔbea fi ase wɔ ɔhyew a ɛba fam te sɛ digrii 130 mu wɔ nkwammoaa a wɔayɛ wɔn ayayade mu.

Ahobanbɔ a eye ne ɛka a ɛba fam ho mmɔdenbɔ no maa LiMn2O4 (lithium manganese oxide) bae wɔ-1990 mfe no mfinimfini. Manganese yɛ efĩ a ne bo nyɛ den na spinel nhyehyɛe no fi awosu mu yɛ nea ɛyɛ den kɛse. Saa nkwammoaa yi renguan kosi sɛ wobɛboro 250℃typically. Nneɛma a wɔde di gua no? Ahoɔden a ɛwɔ mu no so tew kɔ 100-120 Wh/kg, na manganese no petepete electrolyte no mu bere tenten, titiriw wɔ ɔhyew a ɛkɔ soro mu. Cycle asetena hu amane-worehwɛ ebia 300-700 cycles ansa na capacity akɔ fam ase 80%.

LiFePO4 (lithium iron phosphate) daa adi bɛyɛ afe 2001 na ɛsesaa ahobammɔ ho nkɔmmɔbɔ no. Olivine nhyehyɛe no yɛ abotan-a ɛyɛ den wɔ ɔhyew mu; thermal runaway mma kosi sɛ ɛbɛboro digrii 270 , na saa bere no mpo ɛnyɛ basabasayɛ pii. Cycle nkwa yɛ soronko-2,000+ cycles to 80% capacity yɛ standard, na wɔasɔ nkwammoaa binom ahwɛ atwam 5,000 cycles. Nea enye wɔ ho ne voltage: 3.2V nominal pɛ, na ahoɔden density yɛ 90-120 Wh/kg anohyeto. Afei nso, na phosphate tumi krataa tebea no yɛ basabasa mfe pii.

NMC (lithium nickel manganese cobalt oxide) ne NCA (lithium nickel cobalt aluminium oxide) puei sɛ nnuru a "ɛkari pɛ". Ɛdenam nickel, manganese, ne cobalt a wode frafra mu wɔ nsusuwii ahorow mu-nea ɛtaa ba ne NMC 111, 532, 622, ne 811 a akontaahyɛde no kyerɛ dade a ɛwɔ mu no-wubetumi asiesie adwumayɛ no. Nikel a ɛkɔ soro no pia ahoɔden a ɛwɔ mu no kɔ soro kɔ 200-250 Wh/kg nanso ɛma ɔhyew a ɛgyina pintinn ne kyinhyia nkwa nna ho ka. NMC 811 nkwammoaa tumi bɔ 250 Wh/kg nanso ehia sɛ wɔde ahwɛyiye kɛse di ɔhyew ho dwuma.

Wɔ anode fã no, graphite ayɛ gyinapɛn fi da a edi kan no. Nsusuwii tumi yɛ 372 mAh/g, na aguadi nkwammoaa taa nya 340-360 mAh/g. Lithium no hyɛ graphene layers ntam bere a ɛrebɔ charge no, na ɛtrɛw graphite dodow no mu bɛyɛ 10%. Saa mfiri mu nhyɛso yi boa ma tumi a wɔde di dwuma no yera wɔ sakre so.

Silicon anodes ayɛ "ade kɛse a edi hɔ" bɛyɛ mfe dunum ni. Silicon nsusuwii tumi yɛ 4,200 mAh/g-boro graphite mmɔho du. Ɔhaw ne sɛ, silicon trɛw 300% bere a ɛtwetwe lithium no. Eyi ma anode no mu paapae wɔ kyinhyia kakraa bi akyi. Mprempren akwan horow no de silicon-graphite afrafra a silicon dodow taa nnu 10% di dwuma de ma ntrɛwmu no kɔ so yɛ nea wotumi di ho dwuma. Ɛno mpo no, nea edi kan-kyinhyia tumi a wɔhwere a wontumi nsakra no tu mmirika 15-25% wɔ anodes a silicon wom mu kyerɛ 5-10% ma graphite kronkron.

Ebia nkwammoaa a ɛte sɛ kurukuruwa ne nea nnipa dodow no ara yɛ ho mfonini bere a wosusuw sɛ "batere" no. 18650 format (18mm diameter, 65mm length) no bɛyɛɛ nea ɛwɔ baabiara bere a laptop yɛfo yɛɛ standardized wɔ so wɔ 2000 mfe no mfiase mu hɔ. Tesla agye din sɛ ɔde wɔn mpempem pii dii dwuma wɔ mfitiase Roadster no mu. Typical 18650 tumi runs 2,000-3,500 mAh gyina chemistry ne sɛ ebia wo optimize ma ahoɔden anaa tumi.

21700 format foforo (21mm × 70mm) a Tesla ne Panasonic boom yɛɛ no ma ahoɔden bɛyɛ 50% pii wɔ cell biara mu-4,000-5,000 mAh no abu so mprempren. Diameter kɛse no ma nneɛma a ɛyɛ adwuma ne nneɛma a ɛnyɛ adwuma (mprempren collectors, can, ahobammɔ mfiri) ratio kɔ soro, na ɛma ahoɔden density tu mpɔn wɔ pack level. Na ɛsɛ sɛ wɔsan yɛ nnwinnade a wɔde yɛ nneɛma foforo, na ɛno yɛ nea enti a gyee bere kakra a wɔfaa wɔn sɛ wɔn mma no fã.

Prismatic nkwammoaa fi ɔpɛ a kar adwumayɛfo wɔ sɛ wɔde ahunmu bedi dwuma yiye no mu. Sɛ́ anka wode cylinders bɛhyɛ adaka bi mu ma na woagyaw saa baabi a ɛda hɔ kwa no nyinaa no, woyɛ nkwammoaa a ɛyɛ ahinanan a ɛboaboa ano yiye. Kar-grade prismatic nkwammoaa fi 20Ah kosi bɛboro 100Ah tumi. Ɛnyɛ den sɛ wobɛhwɛ so wɔ ɔhyew-fi nneɛma a wɔde kyekyere nneɛma mu efisɛ wubetumi de mprɛte a ɛma onwini ahyɛ afã horow a ɛyɛ tratraa no so tẽẽ. Nea enye wɔ ho ne sɛ woanya wo nkesua nyinaa wɔ nketewa kakraa bi mu-sɛ prismatic cell kɛse biako di nkogu a, wohwere tumi pii sen sɛ cylindrical cell ketewa biako di nkogu.

Pouch cells de ahunmu a wɔde di dwuma yiye ho adwene no kɔ akyiri denam dade toa no a woyi fi hɔ koraa no so. Wɔde aluminum-laminate kotoku a ɛyɛ mmerɛw ahyɛ nkwammoaa no mu. Eyi gye ebia 10-15% mu duru versus prismatic can, na format no yɛ flexible yiye-wubetumi ayɛ wɔn kɛse anaa nsusuwii biara a application no hwehwɛ. Wɔn a wɔyɛ EV no ani gye wɔn ho efisɛ wubetumi de ahyɛ mprɛte a ɛma onwini mu tẽẽ. Mmerewa no yɛ mfiridwuma: wohia abɔnten so nhyɛso na wɔasiw electrode delamination ano bere a wɔretu sakre no, na wɔyɛ mmerɛw kɛse sɛ wɔbɛsɛe wɔn wɔ puncture mu.

Lithium Ion Battery Technology

Separator no nnya adwene pii, nanso akyinnye biara nni ho sɛ ɛyɛ ahobammɔ fã a ɛho hia sen biara. Ɛyɛ teateaa (16-25 μm mpɛn pii) porous membrane a ɛma anode ne cathode no ntumi nka bere a ɛma lithium ions fa mu. Nneɛma a wɔde yii nneɛma mu mfiase no yɛ polyethylene (PE) a ɛwɔ ɔfa biako anaa polypropylene (PP).

Nnɛyi mpaapaemu a ɛyɛ adwuma a ɛkorɔn-de trilayer nhyehyɛe di dwuma, mpɛn pii no PP/PE/PP. PE layer no wɔ nwene a ɛba fam (135℃) sen PP (165℃). Sɛ nkwammoaa no fi ase yɛ hyew dodo a, PE no nwene na ɛhyɛ ntini no mu ma, na ɛma ionic akwantu no tom ansa na ɔhyew no adu baabi a asiane wom. Wɔfrɛ eyi thermal shutdown, na ɛyɛ wo kwan a etwa to a wode bɛbɔ wo ho ban ansa na thermal runaway.

Ceramic-coated separators de ahobammɔ foforo ka ho. Alumina anaa dɔteɛ nketenkete foforɔ a wɔde akata so teateaa (2-4 μm) wɔ separator no afã baako anaa mmienu no nyinaa ma structure no mudi mu kura sɛ polymer no nwene mpo a. Nneɛma a wɔde kata so no yɛ porous araa ma ionic transport kɔ so, nanso ɛmma electrode no ntumi nkɔ tiawa-wɔ ɔhyew a ɛboro digrii 150 mpo mu. Nea enye wɔ ho ne ɛka-ceramic-coated separators run 2-3× bo a standard separators-ne kakra a ɛkorɔn impedance.

Porosity taa tu mmirika 40-50%. Ɛba fam dodo na ionic resistance kɔ soro, na ɛto tumi tumi ano hye. Ɛkɔ soro dodo na mfiri ahoɔden hu amane. Pore kɛse kyekyɛ nso ho hia; Gurley nɔma (mframa a ɛtumi fa mu sɔhwɛ) no yɛ standard spec. EV-grade mpaapaemu dodow no ara de wɔn ani si sikani 200-400/100cc so.

Electrolyte a ɛwɔ lithium ion cell mu no yɛ nea ɛyɛ den sen sɛnea ebia wubesusuw. Base formulation taa yɛ lithium nkyene-LiPF3 (lithium hexafluorophosphate) a ɛwɔ nkwammoaa 95%+ mu-a wɔapete wɔ organic carbonates afrafra mu. Nneɛma a wɔtaa de yɛ aduru no bi ne ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ne ethyl methyl carbonate (EMC).

LiPF2 dodow taa yɛ bɛyɛ 1.0 kosi 1.2 M (molar). Sɛ ɛboro so a, ɛma ionic conductivity tu mpɔn kodu baabi, nanso ɛboro 1.3 M anaa nea ɛte saa so no wufi ase nya nkyene a ɛtɔ wɔ ɔhyew a ɛba fam mu. LiPF2 wɔ nsɛm-ɛyɛ nsuo-te nka na ɛhyɛ aseɛ porɔw boro digrii 60 -nanso akwan foforɔ te sɛ LiBOB anaa LiFSI nnya ntu mfi hɔ ɛnam ɛka anaa aguadiɛ foforɔ nti.

Carbonate solvent blend no nya tuned ma dwumadie no. EC wɔ dielectric constant a ɛkorɔn ne SEI-forming su pa, nanso ɛyɛ nwini wɔ 36℃. Ɛsɛ sɛ wode frafra carbonates a ɛba fam-viscosity te sɛ DMC anaa EMC na ama woakura ɔhyew a ɛba fam-adwumayɛ mu. Nnuru a wɔtaa yɛ no betumi ayɛ EC:DMC 1:1 sɛnea ne kɛse te, anaa EC:EMC 3:7. Nkyɛmu pɔtee no yɛ nea ɛyɛ wɔn dea na wɔhwɛ so yiye.

Nneɛma a wɔde ka ho ne baabi a nnuruyɛ mu nkonyaayi ankasa no kɔ so. Nnɛyi electrolytes kura 2-5% wɔ mu duru mu a ɛyɛ nneɛma ahorow a wɔde ka ho a ɛsakra SEI a ɛba, esiw charge a ɛboro so ano, esiw gas awo ntoatoaso ano, anaasɛ ɛma ɔhyew a ɛkorɔn-gyina pintinn tu mpɔn. Ɛkame ayɛ sɛ Vinylene carbonate (VC) a ɛwɔ 1-2% no yɛ amansan nyinaa de a ɛma SEI su tu mpɔn wɔ graphite anodes so. Fluoroethylene carbonate (FEC) yɛ adwuma yiye ma anode ahorow a silicon wom. Saa nnuru yi pɛ sɛ ɛtew so wɔ mfiase charging cycles no mu, na ɛyɛ ahobammɔ layer wɔ anode no so a ɛyɛ ionically conductive nanso electronically insulating.

Overcharge ahobammɔ additives te sɛ biphenyl anaa cyclohexylbenzene fi ase polymerizing bɛyɛ 4.5V, ma emu shunt a ɛmma voltage nkɔ soro nkɔ akyiri. Eyi ma wunya ahobammɔ bi sɛ BMS no di nkogu a, ɛwom sɛ ɛda adi sɛ sɛ wode wo ho to so a, ɛnyɛ adeyɛ a eye sen biara de.

Ebia SEI no ne ade a wɔnte ase kɛse nanso ɛho hia sen biara wɔ lithium ion batere adwumayɛ mu. Wɔ charging cycles kakraa bi a edi kan no mu no, electrolyte afã horow no ne anode no ani yɛ adwuma, na ɛyɛ pasivation layer. Saa ɔfa yi ho hia: ɛsɛ sɛ ɛyɛ nea ɛde ion kɔ (na ama lithium ions atumi afa mu) nanso ɛde ɛlɛtrɔnik kwan a ɛbɔ ho ban (na amma electrolyte no ansɛe bio). SEI a wɔahyehyɛ no yɛ basabasa-lithium nkyene, organic compounds, ne polymers du du pii a wɔafrafra mu wɔ layer a ne kɛse yɛ 10-100 nm mu.

SEI a wɔhyehyɛ no yiye yɛ nsonsonoe a ɛda nkwammoaa a ɛkyinkyini mpɛn 500 ne nea ɛkyinkyini mpɛn 3,000 ntam. Ɔhaw no ne sɛ SEI no nyɛ static. Ɛpaapae bere a anode no mu nne kɛse sesa no, na ɛda baabi a ɛyɛ foforo a edi electrolyte ne lithium pii de siesie nneɛma a asɛe no adi. Eyi nti na tumi no yera wɔ sakre so bere mpo a woreyɛ brɛoo wɔ nkwammoaa no ho no.

Formation cycling yɛ anammɔn a ɛho hia a wɔde yɛ nneɛma. Nkwammoaa fa charge-discharge cycles biako anaa nea ɛboro saa a ɛyɛ brɛoo wɔ ɔhyew a wɔahyɛ so mu de si SEI a edi kan no so. Formation protocols yɛ proprietary, nanso typical first-cycle charging rates yɛ C/20 kosi C/10, na adeyɛ no betumi agye nnɔnhwerew 24-48. Wɔn a wɔyɛ nneɛma no ma formation voltage anohyeto, ɔhyew, ahomegye bere, ne sakre ho nhyehyɛe yɛ papa na ama wɔanya SEI a ɛyɛ den sen biara. Sɛ wunya eyi wɔ ɔkwan a ɛnteɛ so a, ɛma wohwere sakre nkwa.

Kalenda onyin-tumi a ɛyera mpo bere a nkwammoaa no te hɔ ara kwa-yɛ SEI adeyɛ kɛse nso. SEI no kɔ so nyin nkakrankakra wɔ open circuit mu, na ɛdi lithium a wotumi de di dwuma. Sɛ wɔkora so wɔ tebea a ɛyɛ den ne ɔhyew a ɛkɔ soro mu a, ɛma eyi yɛ ntɛmntɛm. Cell a wɔde asie wɔ 100% SOC ne 60℃betumi ahwere 20% tumi wɔ afe biako mu, bere a cell koro no ara a ɛwɔ 50% SOC ne 25℃betumi ahwere 3%.

Lithium ion nkwammoaa no te nka sɛ ɛbɔ boro so, ɛbɔ boro so, na ɛbɔ boro so, na ɛbɔ wɔ ɔhyew a ɛmfata mu. Wei nti na multi-cell battery pack biara hia BMS (battery management system).

Ɔkwan a wɔfa so de charge a ɛyɛ gyinapɛn ne current current/constant voltage (CC-CV). Wɔ CC fa no mu no, wopia current kɔ cell no mu wɔ fixed rate-taa yɛ 0.5C kɔ 1C ma cell dodow no ara, ɛwom sɛ ebinom high-power cells tumi di 3C anaa nea ɛboro saa ho dwuma. Voltage kɔ soro bere a cell no rebɔ charge no. Sɛ voltage du anohyeto a ɛwɔ soro (4.2V ma nnuru dodow no ara, 3.65V ma LFP, 4.3V anaa 4.35V ma NMC ahorow bi a ɛkorɔn-ahoɔden) a, wodan kɔ CV mode so. Current no brɛ ase bere a cell no bɛn charge a edi mũ no, na mpɛn pii no ɛtwa bere a current no kɔ fam sen C/20 anaa C/50 no.

Fast charge yɛ nea ɛyɛ den kɛse. Charge rates a ɛkorɔn ma lithium plating yɛ ntɛmntɛm wɔ anode no so, a ɛyɛ asiane-metallic lithium yɛ reactive kɛse na ebetumi ama emu shorts anaa dendrite formation a ɛhyɛn separator no mu aba. Sɛ wopɛ sɛ wobɔ ntɛmntɛm-bɔ dwoodwoo a, ɛsɛ sɛ wote sɛnea voltage, current, ne temperature ne lithium plating mfiase tebea horow di nkitaho no ase.

Asɛm no ne sɛ wuntumi nsusuw lithium plating tẽẽ wɔ cell a wɔatoto mu mu. Ɛsɛ sɛ wufi nsɛnkyerɛnne afoforo mu kyerɛ. Ɔkwan biako ne sɛ wobɛdi anode tumi akyi ne lithium dadeɛ nkyerɛkyerɛmu. Sɛ anode tumi kɔ fam 0V versus Li/Li+ a, plating rekɔ so. Ɔhaw no ne sɛ, nkwammoaa dodow no ara a wɔtɔn no nni reference electrodes.

Ɔhyew a ɛkɔ soro bere a wɔde charge ntɛmntɛm nso ho hia. Nkwammoaa a ɛrebɔ wɔ 2C betumi ahu sɛ ne mu hyew akɔ soro digrii 15-20 sen baabi a atwa yɛn ho ahyia mpo bere a onwini a ɛyɛ nnam no. Wɔ awɔw mu hyew mu no, eyi boa ankasa-nwini nkwammoaa (ka sɛ -10℃) nni ahoɔden tumi a enye koraa, nanso sɛ wubetumi ayɛ no hyew denam charge a wobɛbɔ wɔ dodow a ɛkɔ fam (0.5C) so a, adwumayɛ tu mpɔn. EV ahorow bi hyɛ da yɛ eyi ankasa: wɔ wim tebea a ɛyɛ nwini mu no, wɔbɛma batere no ayɛ hyew bere tiaa bi de ayɛ batere no hyew ansa na ofirikafo no ahwehwɛ ahoɔden kɛse na ama watumi ayɛ ntɛmntɛm.

Nkwammoaa a ɛkari pɛ ho hia efisɛ nkwammoaa a ɛtoatoa so no ntra hɔ pɛpɛɛpɛ da. Manufacturing tolerances, nsonsonoe nketenkete a ɛwɔ self-discharge rates mu, ne thermal gradients a ɛwɔ pack no nyinaa mu no ma voltage drift. Sɛ wo charge series string a wonkari pɛ a, cells binom bɔ upper voltage anohyeto no ansa na afoforo. Nkwammoaa a ɛyɛ den no nnya ahoɔden pii, nkwammoaa a ɛyɛ mmerɛw no nnya ahoɔden boro so, na adwumayɛ ho hu.

Passive balancing de resistors di dwuma de mogya fi ahoɔden fi higher-voltage cells mu. Ɛyɛ mmerɛw na ne bo nyɛ den nanso ɛsɛe ahoɔden sɛ ɔhyew. Active balancing de DC-DC converters anaa capacitors di dwuma de ahoɔden fi nkwammoaa a ɛkorɔn mu kɔ nkwammoaa a ɛba fam mu. Ɛyɛ adwuma yiye, ɛyɛ den, ne bo yɛ den. Wɔ 400V EV pack ho no, passive balancing betumi asɛe 50-100W daa, a ɛyɛ nea wontumi mmu ani ngu so sɛ wɔde toto karka tumi ho nanso ɛka bom bere kɔ so.

Lithium Ion Battery Technology

Ɔhyew a ɛba wɔ lithium ion nkwammoaa mu no fi mmeae abiɛsa: ɔhyew a wontumi nsakra (Joule ɔhyew a efi emu ahoɔden mu), ɔhyew a wotumi dannan (entropy nsakrae a ɛba wɔ electrochemical reaction no mu), ne ɔhyew a efi afã horow a ɛyɛ adwuma mu. Wɔ C- dodow a ɛba fam kosi nea ɛkɔ fam mu no, ɔhyew a wotumi dannan no na edi tumi. Wɔ C- dodow a ɛkorɔn mu no, ɔhyew a wontumi nsakra no gye dibea.

Ɔhyew asɛmfua a wotumi dannan no yɛ anigye efisɛ ɛsakra sɛnkyerɛnne gyina SOC so. Wɔ lithium ion nnuru dodow no ara mu no, charge ma ɔhyew ba wɔ SOC a ɛba fam nanso ɛtwetwe ɔhyew wɔ SOC a ɛkorɔn mu. Discharging yɛ nea ɛne eyi bɔ abira. Crossover point no bɛyɛ 50-60% SOC mpɛn pii. Eyi nti na ebia wubehu sɛ nkwammoaa mu hyew so tew ankasa wɔ charge no fã a etwa to no mu sɛ current no sua sɛnea ɛsɛ a.

Ɛsono sɛnea ɛko tia wɔ nipadua no mu sɛnea ɔhyew, SOC, ne onyin te. Wɔ 25℃, 18650 nkwammoaa foforo betumi anya 40-60 miliohms DC resistance. Wɔ -20℃, ɛno betumi ahuruw akodu 200-300 milliohms. Eyi nti na EV ahorow a ɛwɔ wim tebea a ɛyɛ nwini mu no so tew kɛse no. Ɛnyɛ sɛ nnuruyɛ yɛ brɛoo wɔ ɔhyew a ɛba fam nko, na mmom emu ahoɔden a ɛko tia no kɔ soro no kyerɛ sɛ batere no ahoɔden pii sɛe bere a ɔhyew a ɛwɔ nkwammoaa no mu no.

Ɔhyew a wɔde guan no gyina nnuruyɛ so. Wɔ NMC nkwammoaa fam no, exothermic decomposition reactions fi ase bɛyɛ 180-220℃. Sɛ wofi ase wie a, ɔhyew betumi akɔ soro digrii 10-50 wɔ sekan biara mu, na adu digrii 800 anaa nea ɛboro saa. LFP yɛ nea ahobammɔ wom kɛse; thermal runaway onset yɛ 270℃+ na ɔhyew a ɛsen biara a wodu ho no sua.

Nkwammoaa a ɛwɔ pack mu ntam a ɛtrɛw no ne asiane ankasa. Sɛ nkwammoaa biako kɔ thermal runaway mu a, ɛma n’afipamfo yɛ hyew. Sɛ́ ebia nkwammoaa a ɛbemmɛn no nso guan no gyina sɛnea wotumi ma onwini, nkwammoaa no ntam kwan, ne nneɛma a wɔde siw ano so. UL 9540A propagation testing yɛ eyi ho mfonini denam nkwammoaa biako a wɔhyɛ ma ma ɔguan fi ɔhyew mu na wɔhwɛ sɛ ebia nkwammoaa a ɛbɛn ho no di akyi anaa. Pack nhyehyɛe pa kura huammɔdi a ɛkɔ cell biako anaasɛ anyɛ yiye koraa no module ketewaa bi.

Ɛsono akwan horow a wɔfa so ma onwini. Mframa a ɛma onwini yɛ mmerɛw sen biara-bɔ mframa fa nkwammoaa anaa pack no so. Ɛyɛ adwuma OK ma ahoɔden a ɛba fam dwumadie te sɛ PHEVs anaa ahoɔden akoraeɛ nhyehyɛeɛ. Nsuo a ɛma onwini ho hia ma EV ahorow a ɛyɛ adwuma yiye-. Nsusuwii dodow no ara de nsu 50:50-glycol afrafra a ɛyɛ lita 10-25 simma biara di dwuma denam mprɛte a ɛyɛ nwini anaa akwan a ɛma onwini so. Wɔtaa hwɛ ɔhyew a ɛkɔ mu no so ma ɛyɛ digrii 20-35 . Ɛsɛ sɛ battery pack temperature gradients tra ase 5℃max to min na wɔakwati sɛ nkwammoaa a ɛyɛ hyew sen biara no nyin ntɛmntɛm.

Nsɔhwɛ nhyehyɛe ahorow bi de frigye a ɛma onwini, onwini a wɔde gu nsu mu wɔ dielectric nsu mu, anaa nneɛma a wɔde sesa phase-di dwuma. Fridge mu onwini betumi atwe ɔhyew pii afi mu nanso ɛhwehwɛ sɛ wɔyɛ AC nhyehyɛe a ɛyɛ den kɛse. Immersion cooling wɔ heat transfer coefficients a ɛyɛ papa (500-2,000 W/m2K versus 50-150 W/m2K ma indirect liquid cooling) nanso sealing ne nsuo a ɛne ne ho hyia yɛ nsɛnnennen. PCM ahorow yɛ adwuma a ɛnyɛ hwee nanso ɛsɛ sɛ wɔpo ɔhyew a wɔde asie no awiei koraa no, enti ɛboa titiriw wɔ bere tiaa mu onwini mu bere a wɔrebɔ ntɛmntɛm anaasɛ ɛreyɛ ntɛmntɛm denneennen no.

Capacity fade ne impedance growth ne akwan titiriw abien a ɛma nneɛma sɛe. Wɔde honam fam ne nnuru mu nneɛma ahorow pii a ɛkɔ so bere koro mu na ɛde ba.

Wɔ anode fã no, SEI nyin di cyclable lithium ne electrolyte, na ɛma ahoɔden a ɛko tia no yɛ kɛse. Graphite exfoliation betumi aba sɛ wɔde charge ahyɛ nkwammoaa no mu wɔ ɔhyew a ɛba fam-lithium mprɛte a ɛwɔ graphite no ani sen sɛ ɛbɛkɔ mu, na sɛ awiei koraa no ɛkɔ mu a, ɛbubu graphite nhyehyɛe no mu. Mpɛn pii no, eyi yɛ nea wontumi nsakra. Binder a ɛporɔw wɔ ɔhyew a ɛkɔ soro mu no ma anyinam ahoɔden a ɛda nneɛma nketenkete ntam no yera.

Cathode a wɔsɛe no no bi ne nsakrae dade a wɔpete (titiriw manganese a ɛwɔ LMO anaa manganese-a NMC wom mu), nhyehyɛe mu nsakrae a efi lithium a wɔde hyɛ mu/yiyi mu mpɛn pii, ne soro a wɔsan yɛ wɔ nikel cathode a ɛkorɔn-mu. Nsakrae dade a wɔapete no tu kɔ anode no mu baabi a ɛma SEI nyin, enti cathode a wɔsɛe no ma anode no sɛe ntɛmntɛm wɔ ɔkwan a ɛnteɛ so.

Electrolyte a ɛporɔw ne gas a ɛba no yɛ ɔhaw akɛse wɔ ahoɔden a ɛkɔ soro ne ɔhyew a ɛkɔ soro mu. Mframa a ɛtaa ba no bi ne CO2, CO, ne hydrocarbon ahorow a efi carbonate a ɛporɔw mu. Wɔ kotoku nkwammoaa mu no, wubehu sɛ kotoku no ahonhon wɔ ɔkwan a wotumi hu so. Wɔ cylindrical anaa prismatic cells a ɛwɔ cases a ɛyɛ den mu no, nhyɛso no kɔ soro kosi sɛ ahobammɔ mframa no bebue (mpɛn pii no wɔ 10-15 bar).

Lithium a wɔhwere no yɛ ade titiriw a ɛma ɛyera. Bere biara a SEI no nyin anaasɛ lithium mprɛte bɛkɔ anode no so a wontumi nsakra no, woyi lithium bi fi lithium a wotumi kyinhyia no ɔtare no mu. Awiei koraa no, wo sa na wo tumi so tew.

Di nkogu mpofirim betumi afi ntade tiaa a ɛwɔ mu no mu aba. Ntama ntiantiaa dodow no ara fi ase ketewaa-dade ketewaa bi tow nea ɛpaapae no, anaasɛ lithium dendrite nyin fa mu. Tiatiaa no ma beae a ɛyɛ hyew ba, a ɛma ɔsɛe no yɛ ntɛmntɛm wɔ mpɔtam hɔ, na ɛma tiawa no yɛ bɔne, na wunya nsɛm pa a wɔde ma. Ɛtɔ da bi a, nkwammoaa no ankasa-sa yare sɛ tiawa no nwene ne ho bue a. Mmere foforo nso ɛkɔ so kɔ thermal runaway.

Nnadewa a wɔde hyɛn mu ho sɔhwɛ ahorow (a wɔhyɛ dade nnadewa ma ɛfa nkwammoaa a wɔde ahoɔden ahyɛ mu ma mu) yɛ sɔhwɛ a wɔde di dwuma ɔkwammɔne so a wɔtaa yɛ. Mpɛn pii no, LFP nkwammoaa nkɔ ɔhyew a guan fi nnadewa a ɛkɔ mu no mu. NMC nkwammoaa taa yɛ saa, ɛwom sɛ ɛtɔ mmere bi a nhyehyɛe ahorow a ɛwɔ mpaapaemu a eye na ahoɔden pɔtee bi a ɛba fam betumi atwam de.

Mfonini 5 kyerɛ tumi a wɔkora so ne kyinhyia dodow ma nnuru pii wɔ kyinhyia tebea a ɛyɛ mmerɛw mu (1C charge/discharge, 25℃, 100% DOD).

Worentumi nsusuw ahoɔden dodow a ɛwɔ lithium ion nkwammoaa mu no tẽẽ. Ɛsɛ sɛ wufi susuw afoforo mu bu ho akontaa: ahoɔden, ahoɔden, ne ɔhyew.

SOC akontabuo kwan a ɛyɛ mmerɛw no yɛ voltage-gyina. Chemistry biara wɔ su a ɛbue-circuit voltage versus SOC curve. Sua voltage no bere a cell no agye n’ahome kakra akyi (sɛnea ɛbɛyɛ a bere tiaa mu voltage no bɛkɔ fam afi emu resistance decay mu), hwehwɛ no wɔ OCV curve no so, na wunim SOC. Ɔhaw no ne sɛ, ɛntaa mma sɛ wubenya bere mma nkwammoaa no nnye n’ahome wɔ nneɛma a wɔde di dwuma ankasa mu.

Coulomb akontaabu ne ɔkwan a wɔfa so yɛ ade a wɔahyɛ da ayɛ. Wode current bom bere kɔ so de di charge in ne out akyi. Sɛ wohyɛ aseɛ wɔ SOC a wonim mu a, wobɛtumi abu SOC foforɔ no ho akontaa berɛ biara. Pɛpɛɛpɛ gyina wo mprempren sensor (±0.5% yɛ nea ɛtaa ba) ne nim a wunim tumi ankasa so. Mfomso boaboa ano bere kɔ so, enti ɛsɛ sɛ wosan susuw ho bere ne bere mu denam charge anaa discharge cycle a wobɛyɛ nyinaa so.

Model-gyina akwan so de circuit model a ɛne no sɛ anaa electrochemical model a ɛwɔ cell no mu di dwuma. Wo susuw terminal voltage ne current, tu mmirika fa wo model no mu, na woyi emu tebea horow a SOC ka ho. Kalman filters a wɔatrɛw mu anaasɛ ɔman ahwɛfo a ɛte saa ara abu so. Saa akwan yi betumi ayɛ nea ɛyɛ nokware yiye (±2% SOC mfomso) nanso ɛhwehwɛ sɛ wɔyɛ nhwɛso pa ne akontaabu mu nneɛma a ɛho hia.

SOH akontabuo yɛ den ɛfiri sɛ worebɔ mmɔden sɛ wobɛkyerɛ ɔsɛeɛ dodoɔ, a ɛyɛ brɛoo na ɛkɔ so nkakrankakra. Capacity fade ne impedance growth nnyɛ correlate linearly ne wɔn ho wɔn ho anaasɛ ne cycle count. Cell a wɔayɛ no ntɛmntɛm-charged pii betumi anya impedance a ɛkorɔn nanso moderate capacity fade nkutoo. Cell a wɔde asie wɔ SOC/temperature a ɛkorɔn mu no betumi anya tumi fade kɛse nanso impedance nyin a ɛba fam koraa.

Nnwumayɛbea adeyɛ ne sɛ wɔbɛkyerɛkyerɛ SOH mu a egyina tumi so: nkwammoaa a ɛwɔ ne mfitiase tumi 80% no wɔ 80% SOH, na wɔtaa bu eyi sɛ ɛyɛ nkwa awiei-ma EV dwumadie. Cell no da so ara yɛ adwuma, nanso range no so atew 20%. Wɔ ahoɔden a wɔkora so dwumadie mu no, wobetumi de nkwammoaa adi dwuma akosi 60-70% SOH.

BMS binom yɛ bere ne bere mu tumi nhwehwɛmu-bɔ battery no koraa wɔ rate a ɛba fam mu na wɔsusuw ahoɔden dodow a efi mu ba. Eyi yɛ pɛpɛɛpɛ nanso ɛde ne ho hyɛ mu (batere no nni hɔ bere a wɔreyɛ sɔhwɛ no) na egye nnɔnhwerew pii. Akwan afoforo bɔ mmɔden sɛ wobebu tumi ho akontaa wɔ ɔkwan a ɛnteɛ so afi voltage curves, impedance susuw, anaa coulombic efficiency mu.

Wobetumi asusuw emu ahoɔden denam mprempren pulse a wɔde bedi dwuma ne voltage mmuae a wɔde susuw, anaasɛ AC sɛnkyerɛnne ketewaa bi a wɔde bɛhyɛ mu wɔ frequency ahorow mu (electrochemical impedance spectroscopy). EIS ma nsɛm pii nanso ɛhwehwɛ hardware soronko a ɛntaa mma wɔ aguadi BMS ahorow mu.

Lithium Ion Battery Technology

Sɛ EV batere du nkwa nna awiei-(mpɛn pii no 70{4}}80% wɔ mfitiaseɛ tumi mu) a, ɛda so ara yɛ adwuma pɛpɛɛpɛ ma dwumadie a ɛnyɛ den pii. Batere a wɔde di dwuma wɔ nkwa nna a ɛto so abien mu no renya nkɔso ama ahoɔden a wɔde sie a enhinhim.

Sikasɛm ho nimdeɛ yɛ anifere. Ɛsɛ sɛ wosɔ pack a wɔakɔ pɛnhyen no hwɛ, wubetumi asan ayɛ (sesa BMS, cooling system, anaa module ahorow a asɛe), di adanse ma application foforo no, na wode warranty ma. Eyi nyinaa gye sika. Sɛnea ɛbɛyɛ a ntease bɛba asetena a ɛto so abien- mu no, ɛsɛ sɛ pack a wɔayɛ no foforo no bo sua koraa sen pack foforo a wɔayɛ ama stationary application no. Ɛka no sɛe mpo sɛ refurbishment no nnu 40-50% wɔ pack foforo ka, a egyina nea wogye di ne nhwehwɛmu so.

Nkwammoaa a wɔakɔ pɛnhyen a wɔbɛsɔ ahwɛ no nyɛ -ade ketewaa bi. Module bi betumi akura nkwammoaa ɔhaha pii a ɛwɔ ntoatoaso-parallel. Ɛnyɛ mmerɛw sɛ wobɛsɔ wɔn ahwɛ mmiako mmiako. Wubetumi asɔ module no ahwɛ sɛ unit, nanso cell bɔne biako betumi akata ne ho. Ɛyɛ den sɛ wobehu akwan bi a wɔfa so sɛe ade a wɔansɔ nneɛma a ɛsɛe ade ahwɛ. Asɛmmisa a ɛfa asodi ho nso wɔ hɔ: sɛ batere a ɛto so abien-nkwa mu gya hyew a, hena na ɔde asodi no to no so?

Nneɛma a wɔsan de di dwuma no yɛ -asetra kwan a etwa to-. Mprempren nneɛma a wɔsan de di dwuma kɛse-de pyrometallurgy (smelting) anaa hydrometallurgy (chemical leaching) di dwuma. Pyrometallurgy yɛ mmerɛw nanso ɛnyɛ nea wɔpaw pii-wunya dade a wɔadi afra a ehia sɛ wɔyɛ no yiye bio. Hydrometallurgy tumi san nya dade ankorankoro wɔ ahotew a ɛkorɔn mu nanso ɛhwehwɛ anammɔn pii na ɛma nnuru a wɔsɛe no ba.

Sikasɛm a ɛwɔ nneɛma a wɔsan de di dwuma mu no gyina dade bo so kɛse. Cobalt som bo (bɛyɛ $30-40/kg wɔ abakɔsɛm mu, ɛwom sɛ ne bo kɔ soro kɛse de), enti sɛ wɔbɛsan de nnuru a ɛwɔ cobalt-adeɛ adi dwuma bio a, ɛyɛ sikasɛm mu mfasoɔ. Ɛfata sɛ wɔsan de Nickel di dwuma wɔ nsenia mu. Manganese, dade, ne aluminium yɛ dade a ne bo nyɛ den-, enti ntease wom sɛ wɔbɛsan de adi dwuma titiriw sɛnea ɛbɛyɛ a wɔrenkɔ baabi a wɔtow nneɛma gu. Lithium yɛ anigye-ɛnyɛ nea ɛsom bo titiriw wɔ kilogram biara mu, nanso anohyeto ahorow a ɛwɔ hɔ ma nneɛma a wɔde ma no ma ɛyɛ anigye.

Tẽẽ a wɔsan de di dwuma-batere no a wɔpaapae mu na wɔsan de cathode anaa anode nneɛma di dwuma tẽẽ a ɛnsɛe no nkɔ dade nkyene-yɛ nhwehwɛmu beae a ɛyɛ hyew. Sɛ wubetumi asan anya cathode powder wɔ ɔkwan a wotumi de di dwuma so a, anka wobɛkora ahoɔden ne ɛka a wɔbɔ wɔ cathode synthesis ho no so. Nsɛnnennen no bi ne sɛ wɔbɛtetew nneɛma a ɛyɛ adwuma no afi mprempren nneɛma a wɔboaboa ano ne nea wɔde kyekyere nneɛma ho, na wɔadi nokwasɛm a ɛyɛ sɛ nneɛma a wɔasan de adi dwuma no yɛ nkwammoaa a wɔadi afra a efi wɔn a wɔyɛ, mfe ahorow, ne nnuru ahorow mu no ho dwuma.