Molweni zihlobo!
Emva kokupapashwa kwenqaku Kukho izimvo ezininzi malunga nobungozi bezisombululo ze-Li-Ion zeseva kunye namaziko edatha. Ke ngoko, namhlanje siza kuzama ukuqonda ukuba yintoni umahluko phakathi kwezisombululo ze-lithium ze-UPS kunye nebhetri kwigajethi yakho, ukuba iimeko zokusebenza kweebhetri kwigumbi leseva zihluke njani, kutheni kwifowuni ye-Li-Ion ibhetri ayihlali. ngaphezu kweminyaka eyi-2-3, kwaye kwiziko ledatha eli nani liya kwanda ukuya kwi-10 okanye ngaphezulu kweminyaka. Kutheni ingozi yomlilo we-lithium kwiziko ledatha / igumbi lomncedisi lincinci.
Ewe, izingozi ezineebhetri ze-UPS zinokwenzeka kungakhathaliseki ukuba luhlobo luni lwesixhobo sokugcina amandla, kodwa intsomi "yengozi yomlilo" yezisombululo ze-lithium zoshishino ayinyani.
Ngapha koko, abaninzi baye bayibona loo nto ngebhetri ye-lithium kwimoto ehamba kuhola wendlela? Ke, makhe sibone, siyiqonde, sithelekise...
Apha sibona imeko eqhelekileyo yokuzifudumeza okungalawulekiyo, ukubaleka kwe-thermal yebhetri yefowuni, eyakhokelela kwisiganeko esinjalo. Uya kuthi: APHA! Yifowuni nje, ngumntu ophambeneyo kuphela onokubeka into enjalo kwigumbi lomncedisi!
Ndiqinisekile ukuba emva kokufunda lo mbandela, umfundi uya kutshintsha imbono yakhe ngalo mbandela.
Imeko yangoku kwimarike yeziko ledatha
Akusiyo imfihlo ukuba ukwakha iziko ledatha kukutyalomali olude. Ixabiso lezixhobo zobunjineli kuphela linokuba yi-50% yeendleko zazo zonke iindleko zenkunzi. I-horizon ye-payback imalunga neminyaka eyi-10-15. Ngokwemvelo, kukho umnqweno wokunciphisa iindleko ezipheleleyo zobunini kuwo wonke umjikelo wobomi beziko ledatha, kwaye kwangaxeshanye kunye nezixhobo zobunjineli ezidibeneyo, ukukhulula indawo enkulu kangangoko kunokwenzeka kumthwalo wokuhlawula.
Isisombululo esona sisona sisisombululo esitsha se-UPS yezoshishino esekelwe kwiibhetri ze-Li-Ion, eziye zalahla ixesha elide "izifo zabantwana" ngendlela yobungozi bomlilo, i-algorithms engafanelekanga yokukhutshwa kwentlawulo, kwaye ifumene ubuninzi beendlela zokukhusela.
Ngokunyuka komthamo wekhompyutha kunye nezixhobo zenethiwekhi, imfuno ye-UPS iyakhula. Kwangaxeshanye, iimfuno zobomi bebhetri zonyuka kwimeko yeengxaki zonikezelo lwamandla kwindawo esembindini kunye/okanye ukusilela xa kuqalwa umthombo wamandla ogciniweyo kwimeko yokusetyenziswa/ubukho besethi yejenereyitha yedizili.
Ngokombono wethu, zimbini izizathu eziphambili:
- Ukukhula okukhawulezayo komthamo wolwazi olusetyenzwayo nolugqithiselwayo
Ngokomzekelo, yintoni
kufuneka igcinwe kwaye iqhutywe. - Ukukhula kwindlela yokusetyenziswa kwamandla ombane. Ngaphandle kwendlela eqhelekileyo yokunciphisa ukusetyenziswa kwamandla kwezixhobo ze-IT, ukunciphisa ukusetyenziswa kwamandla athile kumacandelo e-elektroniki.
Igrafu yokusetyenziswa kwamandla kwiziko ledatha enye yokusebenza
Umkhwa ofanayo uboniswa ngoqikelelo lwemarike yeziko ledatha kwilizwe lethu.Ngokutsho kwewebhusayithi, inani elipheleleyo lezithuba ze-rack ezifakwe ekusebenzeni zingaphezulu kwe-20 lamawaka. "Inani lezithuba ze-rack ezifakwe ekusebenzeni ngababoneleli beenkonzo ze-20 ezinkulu zedatha kwi-2017 zanda nge-3% kwaye zafikelela kwi-22,4 lamawaka (idatha ukususela ngo-Oktobha 1, 2017),β - itsho ingxelo yeCNews Analytics. Ngokwee-arhente zokubonisana, ngo-2021 inani lezithuba ze-rack kulindeleke ukuba linyuke ukuya kwi-49 lamawaka. Okokuthi, kwiminyaka emibini umthamo wangempela weziko ledatha unokuphinda kabini. Yintoni le idibene nayo? Okokuqala, ngokunyuka komthamo wolwazi: zombini zigcinwe kwaye zicutshungulwe.
Ukongeza kumafu, abadlali bajonga uphuhliso lwamaziko edatha kwimimandla ukuba ibe ngamanqaku okukhula: bakuphela kwecandelo apho kukho ugcino lophuhliso lweshishini. Ngokutsho kwe-IKS-Consulting, ngo-2016, imimandla ibalwa kuphela i-10% yazo zonke izibonelelo ezinikezelwa kwimarike, ngelixa i-capital kunye nommandla waseMoscow wathatha i-73% yemarike, kunye ne-St. Petersburg kunye nommandla we-Leningrad - i-17%. Kwiingingqi, kuyaqhubeka nokunqongophala kwemithombo yedatha yedatha kunye neqondo eliphezulu lokunyamezela iimpazamo.
Ngo-2025, inani elipheleleyo ledatha kwihlabathi liqikelelwa ukuba linyuke amaxesha e-10 xa kuthelekiswa ne-2016.
Sekunjalo, ikhuselekile kangakanani i-lithium kwiseva okanye kwiziko ledatha le-UPS?
Ukungalungi: ixabiso eliphezulu lezisombululo ze-Li-Ion.
Ixabiso leebhetri ze-lithium-ion lisephezulu xa kuthelekiswa nezisombululo eziqhelekileyo. Ngokutsho kwe-SE uqikelelo, iindleko zokuqala ze-UPS zamandla aphezulu ngaphezu kwe-100 kVA yezisombululo ze-Li-Ion ziya kuba ngamaxesha angama-1,5 aphezulu, kodwa ekugqibeleni ukugcinwa kobunini kuya kuba yi-30-50%. Ukuba sithelekisa nomkhosi-mveliso wamanye amazwe, ke nantsi iindaba malunga nokuqaliswa ngeebhetri zeLi-Ion. Rhoqo, kwiibhetri ze-lithium iron phosphate (LFP kwifoto) zisetyenziswa kwizisombululo ezinjalo ngenxa yexabiso eliphantsi kunye nokhuseleko olukhulu.
Eli nqaku likhankanya ukuba i-100 yezigidi zeedola yachithwa kwiibhetri ezintsha kwi-submarine, makhe sizame ukuyiguqulela kwamanye amaxabiso ...I-4,2 yeetoni zamawaka kukufuduswa ngaphantsi kwamanzi kwinqanawa yaseJapan. Ukufuduswa komphezulu - iitoni ezingamawaka ayi-2,95. Njengomthetho, i-20-25% yobunzima besikhephe yenziwe ngamabhetri. Ukusuka apha sithatha malunga neetoni ezingama-740 - iibhetri ze-lead-asidi. Ukuqhubela phambili: ubunzima be-lithium bumalunga ne-1/3 yeebhetri ze-lead-asidi -> iitoni ezingama-246 ze-lithium. Kuma-70 kWh/kg kwi-Li-Ion sifumana malunga ne-17 MWh yamandla oluhlu lwebhetri. Kwaye umahluko kubunzima beebhetri malunga neetoni ezingama-495 ... Apha asithatheli ngqalelo , ezifuna iitoni ze-14,5 zesilivere kwinqanawa nganye, kwaye ixabisa amaxesha ama-4 ngaphezu kweebhetri ze-lead-acid. Makhe ndikukhumbuze ukuba iibhetri ze-Li-Ion ngoku zi-1,5-2 kuphela amaxesha abiza kakhulu kune-VRLA, kuxhomekeke kumandla esisombululo.
Kuthekani ngamaJapan? Bakhumbula emva kwexesha ukuba "ukukhanyisa isikhephe" ngeetoni ezingama-700 kubandakanya utshintsho elwandle kunye nokuzinza kwalo ... Mhlawumbi kwafuneka bongeze izixhobo ebhodini ukuze babuyisele ukusabalalisa ubunzima boyilo lwesikhephe.
Iibhetri ze-lithium-ion nazo zinobunzima obungaphantsi kweebhetri ze-lead-asidi, ngoko ke uyilo lwenkwili yeklasi ye-Soryu kwafuneka luhlengahlengiswe ngandlela thile ukuze kugcinwe i-ballast kunye nokuzinza.
EJapan, iintlobo ezimbini zeebhetri ze-lithium-ion zenziwe kwaye zaziswa kwimeko yokusebenza: i-lithium-nickel-cobalt-aluminium-oxide (NCA) eveliswe yi-GS Yuasa kunye ne-lithium titanate (LTO) eveliswe yi-Toshiba Corporation. Umkhosi wasemanzini waseJapan uya kusebenzisa iibhetri zeNCA, ngelixa i-Australia yanikwa iibhetri ze-LTO ukuze zisetyenziswe kwiinqanawa ezingaphantsi kwamanzi ze-Soryu kwithenda yamva nje, ngokutsho kukaKobayashi.
Ukwazi isimo sengqondo sokuhlonipha malunga nokhuseleko kwiLizwe leLanga eliPhakamileyo, sinokucinga ukuba imiba yokhuseleko lwe-lithium iye yasonjululwa, yavavanywa kwaye yaqinisekiswa.
Umngcipheko: ingozi yomlilo.
Kulapho siza kufumanisa injongo yopapasho, kuba kukho izimvo ezichaswa ngokugqithisileyo malunga nokhuseleko lwezi zisombululo. Kodwa konke oku kukuthetha, kodwa kuthekani ngezisombululo ezithile zamashishini?
Sele sixoxe ngemiba yokhuseleko kweyethu , kodwa makhe sithethe ngalo mbandela kwakhona. Makhe sijike kumfanekiso, owahlola umgangatho wokukhusela imodyuli kunye ne-LMO / NMC iseli yebhetri eyenziwe yi-Samsung SDI kwaye isetyenziswe njengenxalenye ye-Schneider Electric UPS.
Iinkqubo zemichiza zaxutyushwa kwinqaku lomsebenzisi . Makhe sizame ukuqonda iingozi ezinokwenzeka kwimeko yethu kwaye sizithelekise kunye nokhuseleko lwamanqanaba amaninzi kwiiseli ze-Samsung SDI, eziyinxalenye ebalulekileyo ye-rack ye-G Li-Ion esele yenziwe njengenxalenye yesisombululo esibanzi esisekelwe kwi-Galaxy VM. .
Masiqale nge-flowchart yecala jikelele lemingcipheko kunye nezizathu zomlilo kwiseli ye-lithium-ion.
Ngaphantsi kombhubhisi unokufunda imiba yethiyori yengozi yomlilo yeebhetri ze-lithium-ion kunye ne-physics yeenkqubo.Umzobo webhloko wokuqala wemingcipheko kunye nezizathu zomlilo (Ingozi yoKhuseleko) yeseli ye-lithium-ion ukusuka 2018 iminyaka.
Ekubeni kuxhomekeke kwisakhiwo sekhemikhali yeseli ye-lithium-ion kukho ukungafani kwiimpawu zokubaleka kwe-thermal kwiseli, apha siza kugxininisa kwinkqubo echazwe kwinqaku kwiseli ye-lithium-nickel-cobalt-aluminium (esekelwe kwi-LiNiCoAIO2) okanye iNCA.
Inkqubo yokuphuhlisa ingozi kwiseli inokwahlulwa ibe ngamanqanaba amathathu:
- isigaba 1 (Qala). Ukusebenza okuqhelekileyo kweseli xa ukunyuka kweqondo lobushushu kungadluli kwi-0,2 degrees Celsius ngomzuzu, kwaye iqondo lobushushu leseli ngokwayo alidluli i-130-200 degrees Celsius, kuxhomekeke kwisakhiwo sekhemikhali yeseli;
- isigaba 2, ukufudumala (Ukukhawulezisa). Ngeli nqanaba, iqondo lokushisa liyenyuka, i-gradient yeqondo lokushisa ikhula ngokukhawuleza, kwaye amandla okushisa akhululwe ngokusebenzayo. Ngokuqhelekileyo, le nkqubo ihamba kunye nokukhululwa kweegesi. Ukuguquka kwegesi ngokugqithiseleyo kufuneka kuhlawulwe ngokusebenza kwevalve yokhuseleko;
- Inqanaba lesi-3, ukubaleka kwe-thermal (Ukubaleka). Ukufudumeza ibhetri ngaphezu kwe-180-200 degrees. Kule meko, izinto ze-cathode zingena kwi-reaction disproportionation kwaye zikhupha i-oxygen. Le yinqanaba lokubaleka kwe-thermal, ekubeni kulo mzekelo umxube weegesi ezinokutsha kunye ne-oksijini zingenzeka, eziza kubangela ukutsha okuzenzekelayo. Nangona kunjalo, le nkqubo kwezinye iimeko inokulawulwa, ifundeke - xa ulawulo lwezinto zangaphandle zitshintsha, ukubaleka kwe-thermal kwezinye iimeko kuyeka ngaphandle kwemiphumo ebulalayo yendawo ejikelezileyo. Ukusebenza kunye nokusebenza kweseli ye-lithium ngokwayo emva kwezi ziganeko aziqwalaselwa.
Ubushushu bobushushu bobushushu buxhomekeke kubungakanani beeseli, uyilo lweeseli, kunye nezinto. Iqondo lobushushu le-thermal liyakwazi ukuhluka ukusuka kwi-130 ukuya kuma-200 degrees Celsius. Ixesha lokubaleka kwe-thermal linokwahluka kwaye lisusela kwimizuzu, iiyure okanye iintsuku...
Kuthekani ngeeseli zodidi lwe-LMO/NMC kwii-UPS ze-lithium-ion?
β Ukuthintela ukudibana kwe-anode kunye ne-electrolyte, i-ceramic layer isetyenziswa njengenxalenye yeseli (SFL). Ukuhamba kwe-lithium ion kuvaliwe kwi-130 degrees Celsius.
- Ukongeza kwi-valve yokukhusela i-valve, i-Over Charge Device (OSD) inkqubo yokukhusela isetyenzisiweyo, esebenza ngokubambisana ne-fuse yangaphakathi kunye nokucima iseli eyonakalisiweyo, ukukhusela inkqubo yokushisa i-thermal ukufikelela kumanqanaba ayingozi. Ngaphezu koko, inkqubo ye-OSD yangaphakathi iya kuqala ngaphambili, xa uxinzelelo lufikelela kwi-3,5 kgf / cm2, oko kukuthi, isiqingatha esingaphantsi koxinzelelo lwempendulo yevalve yokhuseleko yeseli.
Ngendlela, i-fuse yeseli iya kusebenza kwimisinga engaphezulu kwe-2500 A ngaphandle kwemizuzwana emi-2. Makhe sicinge ukuba i-gradient yeqondo lokushisa ifikelela ekufundeni kwe-10 degrees C / min. Kwimizuzwana eyi-10, iseli iya kuba nexesha lokongeza malunga ne-1,7 degrees kwiqondo lokushisa layo ngelixa ikwimo yokugqithisa.
- I-separator ye-three-layer kwi-cell kwimodi yokutshaja iya kuthintela utshintsho lwe-lithium ions kwi-anode yeseli. Ubushushu bokuthintela ngama-250 degrees Celsius.
Ngoku makhe sibone into esinayo ngobushushu beseli; Makhe sithelekise ukuba zeziphi izigaba iintlobo ezahlukeneyo zokhuselo ezibangwa kwinqanaba leseli.
- Inkqubo ye-OSD - 3,5 + -0,1 kgf / cm2 <= uxinzelelo lwangaphandle
Ukukhuselwa okongeziweyo kwi-overcurrents.
- ivalve yokhuseleko 7,0 + -1,0 kgf / cm2 <= uxinzelelo lwangaphandle
-Fuse ngaphakathi kwiseli imizuzwana emi-2 kwi-2500A (ngaphezulu kwemowudi yangoku)
Umngcipheko wokubaleka kwe-thermal kwiseli ngokuthe ngqo kuxhomekeke kwiqondo / kwinqanaba lentlawulo yeseli, iinkcukacha ezingaphezulu apha ...Makhe siqwalasele isiphumo senqanaba lentlawulo yeseli kumxholo wemingcipheko yokubaleka kwe-thermal. Makhe siqwalasele itafile yembalelwano phakathi kweqondo lokushisa kweseli kunye neparamitha ye-SOC (iState of Charge, idigri yentlawulo yebhetri).
Inqanaba lokutshajiswa kwebhetri lilinganiswa njengepesenti kwaye libonisa ukuba yimalini intlawulo iyonke esele igcinwe ebhetrini. Kule meko, siqwalasela indlela yokutshaja ibhetri. Kungagqitywa ukuba kuxhomekeke kwikhemikhali yeseli ye-lithium, ibhetri inokuziphatha ngendlela eyahlukileyo xa ihlawuliswa kakhulu kwaye ibe nokuchaphazeleka okwahlukileyo kwi-thermal runaway. Oku kungenxa yomthamo othile owahlukileyo (A*h/gram) weentlobo ezahlukeneyo zeeseli ze-Li-Ion. Ubuninzi besakhono esithile seseli, ngokukhawuleza ukukhutshwa kobushushu ngexesha lokutshaja kwakhona.
Ukongeza, kwi-100% ye-SOC, isiphaluka esifutshane sangaphandle sihlala sibangela ukubaleka kwe-thermal kwiseli. Kwelinye icala, xa iseli ikwi-80% ye-SOC, ubushushu obuphezulu be-thermal obubalekayo beseli bunyukela phezulu. Iseli iya ikwazi ukumelana neemeko ezingxamisekileyo.
Okokugqibela, kwi-70% ye-SOC, iisekethe ezimfutshane zangaphandle zisenokungabangeli ukubaleka kwe-thermal kwaphela. Oko kukuthi, umngcipheko wokutshisa iiseli uncitshiswe kakhulu, kwaye eyona nto inokwenzeka kukuba kukusebenza kuphela kwevalve yokhuseleko yebhetri ye-lithium.
Ukongeza, ukusuka kwitheyibhile sinokugqiba ukuba i-LFP (ijika elimfusa) yebhetri idla ngokunyuka kwamaqondo obushushu, oko kukuthi, inqanaba "lokufudumala" litshintshela kwisigaba "sokubaleka kwe-thermal", kunye nokuzinza kwe-thermal runaway. le nkqubo yokutshaja kakhulu imbi kakhulu. Iibhetri ze-LMO, njengoko sibona, zineempawu zokufudumeza ezigudileyo xa zitshaja kwakhona.
UBALULEKILE: Xa inkqubo ye-OSD iqalisiwe, iseli iphinda imiselwe ukuba idlule. Ngaloo ndlela, i-voltage kwi-rack iyancitshiswa, kodwa ihlala isebenza kwaye inika umqondiso kwinkqubo yokubeka iliso ye-UPS ngokusebenzisa inkqubo ye-BMS ye-rack ngokwayo. Kwimeko yenkqubo ye-UPS yeklasi kunye neebhetri ze-VRLA, isiphaluka esifutshane okanye ikhefu ngaphakathi kwebhetri enye kumtya kunokukhokelela ekungaphumeleli kwe-UPS yonke kunye nokulahlekelwa kokusebenza kwezixhobo ze-IT.
Ngokusekwe koku ngasentla, kwimeko yokusebenzisa izisombululo ze-lithium kwi-UPS, le mingcipheko ilandelayo ihlala ibalulekile:
- I-Thermal runaway yeseli okanye imodyuli ngenxa yesiphaluka esifutshane sangaphandle - amanqanaba amaninzi okukhusela.
- I-Thermal runaway yeseli okanye imodyuli ngenxa yokungasebenzi kakuhle kwebhetri yangaphakathi - amanqanaba amaninzi okukhusela kwiseli okanye kwinqanaba lemodyuli.
- Intlawulo egqithisiweyo-ukhuseleko yi-BMS kunye nawo onke amanqanaba okhuseleko kwi-rack, imodyuli, iseli.
- Umonakalo womatshini awufanelekanga kwimeko yethu, umngcipheko wesiganeko awunanto.
- Ukugqithiswa kwe-rack kunye nazo zonke iibhetri (iimodyuli, iiseli). Ukungacacisi ukuya kuthi ga kwi-70-90 degrees. Ukuba iqondo lokushisa kwigumbi lokufakela i-UPS liphakama ngaphezu kwala maxabiso, kuthetha ukuba kukho umlilo kwisakhiwo. Ngaphantsi kweemeko eziqhelekileyo zokusebenza kweziko ledatha, umngcipheko wesiganeko awunanto.
- Ukunciphisa ubomi bebhetri kumaqondo okushisa aphakamileyo amagumbi - ukusebenza kwexesha elide kumaqondo okushisa ukuya kuma-degrees angama-40 kuvunyelwe ngaphandle kokuncipha okubonakalayo kwibhetri. Iibhetri zelothe zinovelwano kakhulu kuko nakuphi na ukunyuka kwamaqondo obushushu kwaye zinciphisa ubomi bazo obushiyekileyo ngokulingana nokunyuka kobushushu.
Makhe sijonge i-flowchart yomngcipheko weengozi kunye neebhetri ze-lithium-ion kwiziko lethu ledatha, imeko yokusetyenziswa kwegumbi lomncedisi. Masenze lula umzobo omncinci, kuba i-lithium UPS iya kusetyenziswa kwiimeko ezifanelekileyo, ukuba sithelekisa iimeko zokusebenza kweebhetri kwigajethi yakho, ifowuni.
ISIPHELO: Iibhetri ezikhethekileyo ze-lithium kwiziko ledatha kunye negumbi le-server i-UPSs inezinga elaneleyo lokukhusela kwiimeko ezingxamisekileyo, kwaye kwisisombululo esibanzi, inani elikhulu leedigri zokhuseleko olwahlukeneyo kunye neminyaka engaphezu kwemihlanu yamava ekusebenzeni ezi zisombululo zivumela ukuba sithethe ngazo. inqanaba eliphezulu lokhuseleko lobuchwephesha obutsha. Phakathi kwezinye izinto, asifanele silibale ukuba ukusebenza kweebhetri ze-lithium kwicandelo lethu kujongeka njengeemeko "ze-greenhouse" zetekhnoloji ye-Li-Ion: ngokungafaniyo ne-smartphone yakho epokothweni yakho, akukho mntu uya kulahla ibhetri kwiziko ledatha, ukutshisa, ukukhupha. yonke imihla, sebenzisa ngokusebenzayo kwimo ye-buffer.
Unokufumana iinkcukacha ezingakumbi kwaye uxoxe ngesisombululo esithile usebenzisa iibhetri ze-lithium-ion kwigumbi lakho lomncedisi okanye iziko ledatha ngokuthumela isicelo nge-imeyile. , okanye ngokwenza isicelo kwiwebhusayithi yenkampani .
I-TEKNOLOJI EVULAYO -Izisombululo ezibanzi ezithembekileyo ezivela kwiinkokeli zehlabathi, ezilungiselelwe ngokuthe ngqo kwiinjongo zakho kunye neenjongo.
umbhali: Kulikov Oleg
INjineli yoYilo oluKhokelayo
Isebe leZisombululo zoManyano
Inkampani ye-Open Technologies
Ngabasebenzisi ababhalisiweyo kuphela abanokuthatha inxaxheba kuphando. , ndiyacela.
Luthini uluvo lwakho malunga nokhuseleko kunye nokusebenza kwezisombululo zamashishini ezisekelwe kubuchwephesha beLi-Ion?
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16,2%Ingozi, ukuzitshisa, naphantsi kwaziphi na iimeko ndingayifaka kwigumbi lam lomncedisi.11
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10,3%Andinamdla koku, ngoko sitshintsha rhoqo iibhetri zakudala, kwaye yonke into ilungile.7
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16,2%Kufuneka sicinge ukuba ingaba ikhuselekile kwaye iyathembisa.11
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23,5%Inika umdla, ndiza kujonga izinto ezinokwenzeka.16
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13,2%Ndinomdla! Tyala kanye - kwaye ungoyiki ukugqithisa yonke indawo yedatha ngenxa yokusilela kwebhetri enye ehamba phambili.9
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20,6%Inika umdla! Iinzuzo zodlula kude iintsilelo kunye nemingcipheko.14
Bali-68 abasebenzisi abavotileyo. Abasebenzisi abasi-25 abakhange.
umthombo: www.habr.com