Overcurrent kye ki?

Overcurrent kitegeeza nti battery esabibwa okutuusa oba okukkiriza current okusinga bweyazimbibwa. Simple nga ekyo. Akatoffaali kabuguma, kemiko n’afuna situleesi, ebintu ne bigenda ebbali singa tewali muntu yenna ayingira.

Ekizibu kino nkilaba buli kiseera mu nnimiro kidda. Packs zikomawo nga ziriko traces eziyokebwa, melted tabs, cells ezirabika obulungi ebweru naye nga zipima nga zifudde munda. Emirundi mwenda ku kkumi, waliwo eyasika amasannyalaze agasusse oba obukuumi ne bulemererwa.

Obutoffaali bwa lithium bulina ekkomo erikaluba. Akatoffaali akagereddwa ku 10A obutasalako kajja kugumira 10a olunaku lwonna ku bbugumu erya bulijjo. Kinyige ku 15A era ebbugumu ery’omunda lirinnya. Kinyige ku 30A era olina mpozzi seconds nga tonnaba kuwaayo.

okubala emabega waakyo .

Okukola ebbugumu mu katoffaali ka lithium kagoberera i2r. Okuziyiza okw’omunda ku 18650 okwa bulijjo kutuula ku 15-30mΩ okusinziira ku katoffaali n’emyaka gyako. Fumbira ennamba ku katoffaali ka 25mω.

ku 10a: 102 × 0.025=2.5W ku 20a: 202 × 0.025=10W ku 40a: 402 × 0.025=40W

Oyo 40W terina w’egenda munda mu kibbo ky’ekyuma. Ebbugumu ly’obutoffaali ligenda liyitawo. Electrolyte etandika okumenyawo around 80℃. Waggulu wa 130℃, separator esobola okulemererwa. Oluvannyuma lw’ekyo, okudduka okw’ebbugumu kufuuka ekintu ekituufu ekiyinza okubaawo.

Okucaajinga overcurrent kigoberera physics y’emu naye nga kirimu ekizibu eky’enjawulo. Okusiiga Lithium. Push charge current waggulu nnyo ate lithium ebyuma ebiterekeddwa ku anode surface mu kifo ky’okuyingiza obulungi. Okwo plating kwe kufiirwa obusobozi obw’olubeerera. Era kireeta akabi k’okutondebwa kwa dendrite.

awali overcurrent eva mu .

Ennyimpi ez'ebweru .Kibaawo okusinga abakola ebintu bye baagala okukkiriza. Sikulaapu etali nnywevu mu kisenge. Waya eyonoonese ng’esika ku fuleemu. amazzi gayingira nga gakola ekkubo eriyisa amasannyalaze. Nakola ku recall nga pack connector yalina design flaw eyaleka positive pin okukwatagana ne enclosure ground mu kiseera ky'okuyingiza. Enkumi n’enkumi za paaka zaafulumye nga tewali muntu yenna agikwata.

Ensobi mu kutikka emigugu .Laga mu nkola z’ebikozesebwa eby’amaanyi buli kiseera. Brushed motors ziyimiridde ku 6-8x running current. Brushless with FOC control handles stalls better naye nga zikyagenda mu maaso nnyo. Battery elaba spike eyo oba motor controller ekola ekintu kyonna ku nsonga eyo oba nedda.

Ebizibu bya Charger .batera okuba nga ba subtle. Charger eyakolebwa ku 4S pack nga essiddwa mu pack ya 3S. Voltage limits ziyinza okuba nga zikyakola, naye current profile nkyamu. Oba charger sense line ekutuka era charger emala kusika full current okutuusa ekintu lwe kigwa.

Obutakwatagana mu butoffaali .Mu Series Packs ya bukuusa. Obutoffaali buna mu lunyiriri, busatu ku bwo 3000mAh, emu ku zo mu butuufu 2700mAh kubanga yatuula mu sitoowa eyokya okumala emyezi mukaaga. Akatoffaali ako akanafu kasooka kukuba charge full charge. Abalala abasatu basigala nga basika. Akatoffaali ako akanafu kafuna ssente ezisukkiridde, kakola ggaasi, kabugumya, kati olina embeera ya ‘overcurrent’ ey’omu kitundu egenda mu maaso munda mu katoffaali kamu ate nga vvulovumenti ya pack eringa ennungi.

Ebivaamu ebituufu .

Ekivaamu amangu ddala kwe kuba ebbugumu. Sustained Overcurrent ku 2X rating ejja kusika obutoffaali obusinga obungi okuyita ku 60℃mu ddakiika ntono. Akatoffaali kawona, oboolyawo, naye obulamu bw’obugaali butwala hit.

Ebintu ebiddiŋŋana ebivaamu amasannyalaze agasukkiridde bireeta okwonooneka okukuŋŋaanyizibwa. SEI layer ku anode egonvuwa. Okuziyiza okw’omunda kwekulukuunya. Obusobozi buzikira. Akatoffaali akaatandika ku 3000mAh ne 20mΩ kayinza okuba 2400mAh ne 35mΩ oluvannyuma lw’enzirukanya y’okutulugunya 200. Kyandibadde kikola cycle 800 nga kikozesebwa bulungi.

Overcurrent ey’amaanyi-Embeera z’enkulungo ennyimpi-asobola okumaliriza akatoffaali mu sikonda. Akasannyalazo katuuka ku ntikko ku kyonna obutoffaali obuziyiza munda kye bukoma ku. A fully charged high-drain 18650 mu short enkalu esobola okulaba 200-300A current ey’akaseera. Tab welds zitera okuba ekifo ekisooka okulemererwa. Singa tabu zikwata, omuzingo gwa jeeri gubuguma mangu nnyo ne kiba nti okufulumya empewo kugoberera mu sikonda ntono.

Nze ndabye cells that vented so hard the positive cap yatongozebwa okwetoloola laabu. Endabirwamu ez’obukuumi si za kwesalirawo nga ogezesa okuddamu kw’ekitundu ekimpi.

Layers z'obukuumi .

Dizayini ya pack ennungi ekozesa enkola ez’obukuumi eziwera. Tewali kyuma kimu kikwata buli mbeera ya kulemererwa.

PTCs .Tuula munda mu butoffaali obusinga obungi obw’ekika kya ssiringi okuva mu bakola ebintu eby’ettutumu. Batambula nga basinziira ku bbugumu, so si current butereevu. PTC eyinza okuweebwa ekipimo okusobola okukwata 7A n’egenda ku 15A, naye enkola y’olugendo ya bbugumu. Obudde bw’okuddamu bugenda mpola-ebikumi bya milisekondi okutuuka ku sikonda. PTCs tezijja kukuwonya ku short enzibu. Bakwata amasannyalaze agasukkiridde ag’ekigero ne bawa pack obudde okunnyogoga.

FUSES .Fuuwa omulundi gumu era sigala ng’ofuuwa. Pack-Fyuzi z’omutendera ziteekebwa waggulu wa current ya bulijjo ekola nga eriko margin for inrush ne transients. Ekipapula kya 10A ekigenda mu maaso kiyinza okukozesa 15A ekisiibo-okufuuwa fiyuzi. Fiyuzi erongoosa short enzibu ku sipiidi okusinga PTC, mu bujjuvu wansi wa 100ms ku current za high fault. Naye era kitta pack enkalakkalira. Okusaba kwa warranty kugoberera.

Obukuumi ICS .Londoola current okuyita mu sense resistor. Ebitundu ebya bulijjo okuva mu Seiko, TI, n’ebirala biwa emitendera egy’amasannyalaze agasukkiridde (overcurrent thresholds) agasobola okuteekebwa mu pulogulaamu okuyita mu resistors ez’ebweru oba hardcoded munda. Okulwawo okuzuula kukola 8-24ms mu ngeri entuufu. Okuzuula short circuit kwangu, emirundi mingi wansi wa 500μs. IC evuga Fets ez’ebweru okukutula pack.

Omuwendo gwa sense resistor gwe gukulu. A 5MΩ sense resistor egaba resolution esingako naye esuula voltage esingawo era esaasaanya amaanyi mangi ku currents eza waggulu. Resistor ya 2Mω esaasaanya amaanyi matono naye yeetaaga front end esinga okubeera enzibu. Packs ezisinga ez’abaguzi zikozesa 3-10mΩ okusinziira ku kiraasi eriwo kati.

BMS .Mu paaka ennene eyongera amagezi. Active current limiting okusinga olugendo lwokka/nedda-trip. Ebbugumu-Emitendera egy’okuliyirira. Okutema emiti ku bibaddewo mu kuzuula obulwadde. BMS ennungi ekendeeza ku kkomo ery’amasannyalaze agasukkiridde ng’ebbugumu ly’obutoffaali lirinnya, nga likuuma obutoffaali mu ddirisa lyabwo erikola obulungi ne wansi w’emigugu egy’amaanyi.

CIDS .Obutoffaali obw’omunda buwa obukuumi obusembayo-Obukuumi bw’ebyuma. Ekyuma ekisalako ekiriwo kati kikola ku kuzimba kwa puleesa okw’omunda. CID w’egenda okutambula, obutoffaali buba bwafuna dda situleesi ey’amaanyi. CID activation ebiseera ebisinga kitegeeza nti cell eba scrap.

Spec Sheets ne Reality .

Datasheet ratings zitwala embeera ezenjawulo. Samsung 30Q ebalirirwamu 15A continuous etwala 25℃ambient n’okunyogoza okumala. Siba obutoffaali obwo munda mu kiyumba ekiziyizibwa ku 35℃ambient ne 15A kijja kukisika okuyita mu bbugumu eritaliiko bulabe.

Pulse ratings zirabika nga zisikiriza naye nga zijja n’emiguwa nga gikwatiddwa. Akatoffaali kayinza okwewozaako 30A okumala sekondi 10, naye ekyo kitwala nti akatoffaali katandika ku 25℃era kafuna obudde okunnyogoga nga pulse eddako tennabaawo. back-to-back pulses awatali budde bwa kuddamu kukungaanya bbugumu just like continuous current.

Emiwendo gy’okusasula gitera okuba egy’okukuuma okusinga emiwendo gy’okusiibulwa. Akatoffaali akakwata ku 20A discharge kayinza okugumira 4A charge yokka. Lithium plating risk ye nsonga. Obutoffaali obumu obupya obulina silicon-Anode ezikoleddwa mu doped zisinga okuwuliziganya n’omuwendo gwa chajingi.

Emyaka gy’obutoffaali gikyusa buli kimu. Akatoffaali akapya akalina 20mΩ internal resistance kakwata 20A okusinga omwaka-akatoffaali akakadde ku 30mΩ. Obukuumi bwa pack kulina okubala enkomerero-of-okuziyiza obulamu, so si specs z'obutoffaali obupya bwokka.

Okugezesa Obukuumi obusukkiridde amasannyalaze .

Buli design ya pack yetaaga overcurrent validation. Ebikozesebwa mu kugezesa bye bikulu.

Emigugu egy’amasannyalaze gyetaaga okubbira amasannyalaze amangu okusinga obukuumi bwe buddamu. IC y’obukuumi erimu okulwawo okuzuula 10ms yeetaaga omugugu ogutuuka ku current egenderere mu wansi wa 1ms. Slow load ramp-Up ereka olugendo lw'obukuumi nga bukyali era n'ewa obwesige obw'obulimba.

Okupima okuliwo kati kwetaaga bandwidth. Resistors ya 10mω sense ku 100A egaba siginiini ya 1V. Okukwata entikko entuufu kyetaagisa waakiri 10kHz bandwidth, okusinga okusingawo. Scope probes ezirina grounding entuufu Weewale ebizibu by’amaloboozi ebiwa data ya kasasiro.

Okugezesa ebbugumu kukwata ebizibu bya dizayini nti okugezesa ebbugumu mu kisenge kusubwa. Obukuumi IC thresholds drift n’ebbugumu. FET RDS(ON) yeeyongera ku bbugumu erya waggulu, n’eyongerako vvulovumenti okukka. Sense resistor TCR ekola nga resistor ebuguma okuva mu kuyisa current y’ensobi. okugezesa ku -20 diguli , +25 diguli , ne +55 diguli entono.

Matrix y’okugezesa efuna obunene. charge overcurrent, okufulumya overcurrent, short circuit. buli emu ku bbugumu ssatu. Buli emu ku mitendera gya SOC mingi kubanga cell impedance ekyukakyuka ne charge state. Kubisaamu obunene bwa sampuli olw’obwesige mu bibalo. Okukakasa mu bujjuvu kudduka ebikumi n’ebikumi by’ebigezo.

emitendera egy’omugaso .

UL 2054 .Abikka ku battery packs ezitambuzibwa mu butale bwa North America. Okugezesa short circuit kukozesa short enfu okumala sekondi 10. Pack tesaana kukwata muliro oba okubwatuka. Ebbugumu lirondoolebwa naye tewali kkomo lyonna liyitibwa. Eno bbaala esinga obutono.

IEC 62133-2.Ekola mu nsi yonna. Okugezesa okw’ebweru okwa short circuit kukozesa obutasukka 100mω total circuit resistance ekwatibwa okumala essaawa emu oba okutuusa ebbugumu lwe libeera nga litebenkedde. Esinga okukakali okusinga UL 2054 ku bbanga.

UN 38.3.Govers Okutwala ebintu ku nnyanja. Okugezesa 5 kyetaagisa ekimpi okuyita wansi wa 0.1Ω. Obutoffaali oba bbaatule tezirina kusasika oba okukwata omuliro. Kino kikulu kubanga okulemererwa UN 38.3 kitegeeza nti ekintu kyo tekisobola kutambuzibwa mu mateeka.

SAE J2464 .Abikka ku nkola za EV n'ebyetaago ebinywevu. Obuziyiza bwa short circuit bukka ku 5MΩ era emisingi egy’ebbugumu/ebyuma gisinga kuba gya njawulo.

Okuyita ebigezo bino tekitegeeza nti dizayini y’obukuumi nnungi. Kitegeeza nti dizayini y’obukuumi emala okuweebwa satifikeeti. Okutulugunyizibwa okwa nnamaddala-okukozesebwa mu nsi yonna kuyinza okusukka embeera z’okugezesebwa.

Pack Design Okulonda .

Wire gauge ejja buli kiseera. Waya etali ya bunene eyongera resistance era n’ekola ebbugumu ku biyungo. Waya yennyini eyinza okukwata akasannyalazo, naye ebitundu ebinyiga oba ebiyungo bya solder bifuuka ebifo ebibuguma. Packs eziddizibwa ku "battery failure" zitera okulaga terminal za waya eziyokebwa ate obutoffaali buba bulungi.

Okulonda ekiyungo kye kintu ekirala ekinafu. Ebiyungo bya XT60 biweebwa ekipimo kya 60A ekigenda mu maaso, kigambibwa nti. Ekipimo ekyo kitwala crimps ezituukiridde n’okukwatagana okuyonjo. Mu nkola, yagwamu ebitundu 30-40% olw’okwesigamizibwa. Anderson Powerpoles zirina okulowooza okufaananako.

Tab welding ku butoffaali yeetaaga okufaayo. Weld ennungi erina obuziyiza obutono n’amaanyi g’ebyuma. Weld ennyogovu erabika bulungi naye eremererwa wansi w’okukankana oba okuvuga ebbugumu. Weld eyayokebwa yayonoona ekibbo era n’ekola ekifo ekinafu. Enteekateeka za weld zeetaaga okukakasa n’okugezesa okusika n’okupima okuziyiza.

Enzirukanya y’ebbugumu esiba mu busobozi obusukkiridde. Pack erimu active cooling esobola okuyimirizaawo currents eza waggulu okusinga sealed pack nga tewali mpewo ekulukuta. Dizayini ezimu zikozesa thermistors ku butoffaali okutandika okukendeera kw’amasannyalaze nga ebbugumu terinnagenda makulu.

The Takeaway .

Overcurrent etta bbaatule za lithium. Oluusi mangu, oluusi mpola, naye nga bulijjo nkooya. Ekkomo eririwo kati liriwo olw’ensonga ezisibiddwa ku fizikisi ne kemiko, so si kukuuma bukuumi obw’ekimpatiira.

Obukuumi obulungi bwetaaga layers eziwera kubanga buli kika kya protection kirina obunafu. PTCs zigenda mpola. FUSEs ze emu-okukubwa. ICs zisinziira ku butuufu obutuufu. BMS eyongerako ssente n’obuzibu. CIDs kitegeeza nti akatoffaali kaayonoonebwa dda.

Okukebera kwetaaga okulaga embeera z‟okukozesa entuufu n‟embeera z‟okukozesa obubi. Okuyisa ebigezo bya satifikeeti kyetaagisa naye tekimala.

Pack Design Choices-Wire, ebiyungo, ebiyungo, margins-Zilaga oba ddala obukuumi bukuuma oba bulabika bulungi ku lupapula.

Obutoffaali bwe nnesiga buva mu bakola ebintu nga balina omutindo ogukwatagana era nga bafulumya data. Packs ze nnesiga zikozesa circuit z’obukuumi okuva mu batunda ab’ettutumu nga balina dizayini entuufu ey’okukozesa. Ebirala byonna bifuna obujjanjabi n’obwegendereza okutuusa nga bikakasiddwa.