Gabatarwa

Inuwa matsala ce ta gama gari a shigarwar PV na gaske.

Inuwar bishiyoyi, sandunan wutar lantarki, ƙura, najasar tsuntsaye, dusar ƙanƙara, ko da kusurwoyin hawa na module marasa daidaituwa na iya haifar da inuwa ta ɓangare. Inuwa ba kawai tana rage fitowar module ba, tana iya haifar da wani babban matsala: wuraren zafi.

A cikin 'yan shekarun da suka gabata, kwayoyin hasken rana na BC sun jawo hankali sosai a cikin rufin rufi, PV na baranda, da kuma manyan kayayyaki. Babban dalili shi ne: Kwayoyin hasken rana na BC yawanci suna da kyakkyawan juriya ga inuwa, kuma yanayin zafi a wuraren da suke da zafi yana ƙasa a ƙarƙashin inuwa.

A SNEC, sau da yawa kuna ganin masana'antun suna rufe wani ɓangare na layin kwayoyin hasken rana sannan su yi amfani da tsayin ruwa daga famfo don nuna juriyar inuwa na samfuran BC ɗin su.

Don haka me yasa kwayoyin BC suke da wannan fa'ida? Menene ilimin kimiyyar lissafi a bayansa?

Bari mu yi ƙoƙarin bayyana shi cikin sauƙi.

Me yasa Inuwa Ke Haifar da Wuraren Zafi

Me yasa inuwa ke haifar da wuraren zafi?

Kwayoyin hasken rana a cikin wani PV module yawanci ana haɗa su a jere.

Wani da'irar jere yana da siffa ɗaya: wutar lantarki dole ta kasance iri ɗaya a ko'ina.

Wannan yana nufin cewa wutar lantarki ta cikin dukan layin tana ƙayyade ta hanyar madauki gaba ɗaya. Lokacin da kowane kwayar hasken rana ya sami cikakken haske, kowanne yana samar da wutar lantarki kuma duk suna cikin yanayi mai daidaito.

Amma idan tantanin halitta ɗaya ya sami inuwa, halin yanzu da aka samar da hoto zai iya raguwa. Idan dukan layin har yanzu yana buƙatar ɗaukar babban halin yanzu, wannan tantanin da ya sami inuwa zai iya turawa zuwa juyawa baya ta sauran tantannin da ba su da inuwa. A wannan lokacin ya daina zama tushen wutar lantarki kuma ya zama mai amfani da wutar lantarki.

Don inuwa ta ɓangare, tantanin da ya sami inuwa baya daina samar da wutar lantarki gaba ɗaya. Yankin da ba shi da inuwa har yanzu yana samar da ɗan halin yanzu na hoto. Don haka abin da ya kamata ya gudana ta hanyar rushewar juyawa, hanyar zubewa, ko hanyar kewayawa ba shine cikakken halin yanzu na layin ba, amma bambanci tsakanin halin yanzu na layin da halin yanzu da wannan tantanin zai iya samarwa.

Wannan bambanci ana iya kiransa da rashin daidaituwa na halin yanzu:

Imismatch = Istring - Igenerate

Don haka ɓata wutar lantarki a wurin zafi ana iya rubuta shi a takaice:

Photspot ≈ ∣Vrev∣ × Imismatch

wanda shine:

Photspot ≈ ∣Vrev∣ × (Istring - Igenerate)

Wannan dabara tana nuna abu ɗaya mai mahimmanci: a daidai halin yanzu na layin, mafi girman wutar lantarki ta juyawa, mafi yawan wutar da tantanin da ya sami inuwa ke ɓatarwa, kuma mafi zafi wurin zafi ya zama.

Don haka daya daga cikin mabuɗan tsayayya da wuraren zafi shine:

yadda ake rage wutar lantarki mai juyawa akan tantanin da aka inuwa kuma a sanya dumama ta zama daidai.

Wannan shi ne ainihin inda BC cells suke haskakawa.

Yadda BC Cells suka bambanta a Tsari

Yaya BC cell ta bambanta a tsari daga tantanin al'ada?

Tantunan siliki na al'ada yawanci suna amfani da tsarin haɗin gaba da baya.

A taƙaice:

• Gaba yana da layukan grid da busbars, kuma haske yana shiga daga gaba;

• Ana samar da wutar lantarki a cikin tantanin sannan a tattara ta ta hanyar na'urorin gaba da baya.

Tantanin BC, ma'ana Back Contact, yana da fasali guda daya na musamman:

duka na'urorin lantarki masu kyau da marasa kyau suna kan bayan tantanin, babu layukan grid na ƙarfe a gaba.

Wannan yana ba da fa'idodi kai tsaye guda biyu:

1. Babu inuwar layukan grid a gaba, don haka ƙarin yanki mai karɓar haske;

2. Ana iya gina na'urorin baya zuwa tsarin interdigitated, don haka tattara wutar lantarki ya zama daidai.

Hoto 1 Tsarin sashi na BC cell.

Tushen: Calcabrini, A., Procel Moya, P., Huang, B., Kambhampati, V., Manganiello, P., Muttillo, M., Zeman, M., & Isabella, O. (2022). Low-breakdown-voltage solar cells for shading-tolerant photovoltaic modules. Cell Reports Physical Science, 3(12), 101155. https://doi.org/10.1016/j.xcrp.2022.101155

Bayan BC cell yana ɗauke da yankuna p da yankuna n da yawa masu haɗe-haɗe. Tsakanin waɗannan yankuna akwai yawancin gajerun PN junctions masu nauyi. Daga mahangar kewayawa, ba ya zama kamar babban diode guda ɗaya, amma kamar ƙananan diodes da yawa a layi daya. A ƙarƙashin juyar da baya, waɗannan rarraba PN junctions na iya samar da hanyar tafiyar da baya mafi daidaituwa.

Saboda waɗannan PN junctions na baya gajeru ne kuma suna da nauyi a cikin gida, suna iya shiga rushewar baya a ƙaramin ƙarfin juyar da baya.

Tabbas, wannan ya dogara da takamaiman sigogin ƙira na BC cell.

Misali, ƙaramin tazarar da ke tsakanin yankin p da yankin n, mafi ƙarfin filin gida, kuma yawanci yana da sauƙi a samar da ƙaramin ƙarfin juyawa baya. Amma hakan na iya kawo musanya a cikin leakage da shunt resistance. Don haka juriyar inuwa ta tantanin BC ba ƙayyadadden ƙima ba ce. Yana da alaƙa da takamaiman tsarin tantanin, ƙirar bayan fage, girman tazara, yawan doping, ingancin passivation, da tsarin masana'anta.

Dalilin Da Yasa Kwayoyin BC Ke Rasa Ƙarancin Wuta A Ƙarƙashin Inuwa

Me yasa kwayoyin BC ke rasa ƙarancin wuta bayan inuwa?

Lokacin da wani module ya sami inuwa a wani ɓangare, igiyar string tana tura tantanin da aka yi masa inuwa zuwa juyawa baya. Yayin da inuwa ta tsananta, jimillar ƙarfin lantarki a kan wannan substring yana ci gaba da raguwa.

A cikin modules na gargajiya, ana sanya diode bypass a layi daya a kan wani sashe na string. Diode bypass ba a kunna ta ta hanyar mai sarrafawa ba. Na'urar da ba ta aiki ce. Ko tana gudanarwa ya dogara ne kawai da ƙarfin lantarki a kanta. Lokacin da jimillar ƙarfin lantarki na wannan substring ya zama mara kyau sosai, diode bypass yana samun gaba da kuma kunna kai tsaye.

Yanayin kunnawa ana iya rubuta shi kamar:

Vsubstring ≤ -Vf

Vsubstring shine jimlar wutar lantarki na substring ɗin da bypass diode ke karewa;

Vf shine faɗuwar wutar lantarki ta gaba na bypass diode.

Ga substring, jimlar wutar lantarki ɗin za a iya fahimta kamar:

Vsubstring = ∑Vunshaded + ∑Vshaded

inda:

• Kwayoyin da ba a inuwa suna samar da wutar lantarki ta gaba;

• Kwayoyin da aka inuwa suna juyar da baya kuma suna samar da wutar lantarki mara kyau.

Yanayin kunna bypass diode za a iya karanta shi kamar:

∣∑Vshaded∣ ≥ ∑Vunshaded + Vf

A wasu kalmomi:

Jimlar wutar lantarki ta baya na kwayoyin da aka inuwa dole ne ta wuce jimlar wutar lantarki ta gaba na sauran kwayoyin da ba a inuwa, tare da faɗuwar gaba na bypass diode, kafin bypass diode ya kunna.

Amfanin BC modules shine, kafin bypass diode na waje ya kunna, tsarin interdigitated back PN junction na BC cell ɗin kansa yana ba da wasu iyawar juyar da wutar lantarki da aka rarraba. Wannan yana kama da Zener diode da aka gina a cikin cell.

A karkashin juyar da baya, mahaɗar PN na baya na BC cell na iya samar da rarraba juyar da wutar lantarki a ƙaramin ƙarfin lantarki, yana iyakance ƙarin tashin ƙarfin lantarki. Don haka a ƙarƙashin inuwa, lokacin da waje bypass diode bai kunna ba tukuna, BC module na iya ci gaba da samar da wutar lantarki mai girma.

Hoto 2 IV curve na module tare da cell guda ɗaya a inuwa.

Source: E. Özkalay, F. Valoti, M. Caccivio, A. Virtuani, G. Friesen, and C. Ballif, "The effect of partial shading on the reliability of photovoltaic modules in the built-environment," EPJ Photovoltaics, vol. 15, p. 7, Jan. 2024, doi: 10.1051/epjpv/2024001. Available: https://doi.org/10.1051/epjpv/2024001

Kyakkyawan Haƙuri Ba Ya Nufin Kariya Daga Inuwa

Kyakkyawan haƙuri ga inuwa ba ya nufin BC cells ba su da tasiri daga inuwa

Akwai wani kuskuren fahimta da ake buƙatar sharewa.

Kyakkyawan haƙuri ga inuwa ba ya nufin BC cell ba ya shafa daga inuwa.

Kowane PV cell yana samar da ƙarancin wutar lantarki da zarar an rufe shi da inuwa.

Idan yankin da aka yi inuwa a cikin ƙaramin zaren ya yi girma da yawa, ko kuma ƙwayoyin da yawa sun cika inuwa, to jimillar wutar lantarki ta juyar da ƙwayoyin da aka yi inuwa na iya ƙetare jimillar wutar lantarki ta gaba na sauran ƙwayoyin da ba a yi inuwa ba. A wannan lokacin, diode na waje yana kunna.

Da zarar diode na waje ya kunna, wutar lantarki tana zagaya dukan ƙaramin zaren. Ƙwayoyin da ba a yi inuwa ba a cikin wannan ƙaramin zaren suma ana kewaye su, kuma gudummawarsu ga fitarwa tana raguwa sosai. Don haka idan yankin da aka yi inuwa yana da girma, fa'idar samar da wutar lantarki na BC module shima yana raunana.

Yanayin da BC modules ke haskakawa yawanci sune:

• Ɗaya ko ƴan ƙwayoyi suna samun inuwa kaɗan;

• Yankin da aka yi inuwa a kowane ƙaramin zaren ya kasance ƙarami;

• Inuwa tana diagonal, mai siffar tsiri, ko kuma warwatse a gida;

• Diode na waje bai kunna gaba ɗaya ba tukuna.

Misali, inuwa diagonal daga sandar wutar lantarki na iya barin kowane ƙaramin zaren da ƙaramin yanki na inuwa. A wannan yanayin, BC module yakan nuna mafi kyawun juriyar inuwa.

Dalilin da yasa BC Modules ke Gudanar da Wurare Masu Zafi

Me yasa BC modules ke da ƙananan zafin wurare masu zafi?

Akwai manyan dalilai guda biyu da BC modules ke yin hot spots masu sanyi.

Na farko, reverse current ya fi yaduwa

Ga sel na yau da kullun, rarraba reverse current sau da yawa ba daidai ba ne. Reverse breakdown na iya faruwa a wasu wurare masu rauni na gida, kamar:

• Wuraren lahani na gida;

• Gefen sel;

• Rashin daidaituwa na metallization;

• Microcracks ko wuraren da suka gurbata;

• Yankunan da ke da raunin passivation na gida.

Waɗannan wuraren suna aiki kamar maki masu rauni.

Da zarar reverse current ya tattara a waɗannan maki masu rauni, ƙarfin wutar lantarki na gida ya yi yawa sosai, zafin jiki ya tashi da sauri, kuma hot spot bayyananne ya samu.

Kamar amfani da adadin zafi iri ɗaya akan abubuwa biyu:

• Farantin karfe gaba daya;

• Wani tabo mai girman fil.

Na karshen yana yin zafi da sauri tabbas.

Don haka hadarin ga sel na yau da kullun a karkashin inuwa ba "zafi daidai a duk fadin sel" ba ne, amma zafi mai karfi a wuri guda.

Kwayar BC tana da yawancin haɗin PN masu haɗaɗɗiya a bayanta. Gudun juyawa na iya yaduwa cikin sauƙi a kan yankuna da yawa maimakon taƙaita a ƴan wuraren lahani.

Don haka wutar juyawa a cikin kwayar BC tana rarrabuwa daidai, ƙarfin wutar gida ya rage, kuma zafin wuri mai zafi ma ya rage.

Na biyu, ƙarfin wutar juyawa yana ƙasa

Daga tsarin ƙarfin wutar wuri mai zafi:

Photspot ≈ ∣Vrev∣ × Imismatch

a daidai wutar rashin daidaituwa, ƙaramin wutar juyawa yana nufin ƙarancin wutar lantarki.

Shi ya sa ƙaramin wutar juyawa zai iya zama hanyar kariya a yanayin inuwa.

Ga misali mai sauƙi.

Ka ce wutar layin shine 10A kuma kwaya ɗaya ta sami inuwa mai yawa.

Idan kwayar talakawa ta kai wutar juyawa 15V bayan inuwa, ƙarfin wutar da take fitarwa kusan:

P = 15V × 10A = 150W

Idan kwayar BC ta kame saboda tsarin bayanta kuma wutar juyawa ta iyakance zuwa kusan 6V, ƙarfin wutar da take fitarwa kusan:

P = 6V × 10A = 60W

Bambancin a bayyane yake.

Matsayin zafin wuri mai zafi na gaske ya dogara da yankin da aka inuwa, zafin yanayi, saurin iska, rufin module, girman gilashi, ƙirar tantanin halitta, da hanyar gwaji, don haka ba za ku iya tantance shi da lamba ɗaya tsayayye ba.

Amma a wasu gwaje-gwaje na gaske da gogewar filin, modules na BC yawanci suna gudanar da zafin wuri mai zafi ƙasa da na al'ada. Misali, wasu modules na BC na iya kiyaye zafin wuri mai zafi ƙasa da kusan 120 °C, yayin da sauran nau'ikan module na iya kaiwa 160 °C ko ma fiye.

Wasu tantanin halitta na BC da aka ƙera musamman suna samun wani abu kamar "ginannen bypass diode a cikin tantanin halitta." Wannan na iya saukar da zafin wuri mai zafi zuwa kusan 90 °C yayin da module na tunani yake kusa da 190 °C, yana nuna cewa wannan nau'in ƙirar rarraba reverse conduction na iya rage zafin wuri mai zafi sosai.

Shin Ƙananan Reverse Breakdown Voltage Koyaushe Ya Fi Kyau

Shin ƙananan reverse breakdown voltage koyaushe ya fi kyau?

Ba lallai ba.

Ƙananan reverse breakdown voltage yana taimakawa rage zafin wuri mai zafi yayin inuwa, amma kuma yana iya kawo musayar ƙira.

Idan hanyar reverse conduction ba ta da kyau, tana iya ƙara yawan leakage da rage shunt resistance, wanda ke cutar da aikin samar da wutar lantarki na al'ada na tantanin halitta.

Don haka tantanin BC mai inganci yawanci yana buƙatar daidaita manufofi biyu:

1. A lokacin aiki na yau da kullun, kiyaye inganci mai girma, ƙarancin zubewa, da juriya mai girma;

2. Ƙarƙashin inuwa mai juyawa, samar da amintaccen gudanarwa mai juyawa a ƙaramin ƙarfin lantarki.

Wannan kuma shine dalilin da yasa juriyar inuwa ta bambanta tsakanin tantanin BC daban-daban.

Wasu tantanin BC suna karkata zuwa inganci kuma suna iya gina keɓewa mai ƙarfi, don haka ƙarfin lantarki na rushewa yana tafiya sama. Wasu suna karkata zuwa juriyar inuwa kuma suna iya tsara ƙananan hanyoyin rushewa masu daidaituwa.

Don haka ba za ku iya cewa kawai "duk tantanin BC suna da juriyar inuwa iri ɗaya ba." Hanyar da ta fi dacewa ita ce:

tantamin BC da aka tsara da kyau zai iya amfani da tsarin haɗin PN na baya don samun ƙananan rushewa mai juyawa da daidaituwa, kuma hakan yana inganta juriyar inuwa da tabo mai zafi.

Abubuwan Amfanin Tantamin BC A Taƙaice

Abubuwan amfanin tantamin BC a taƙaice

A haɗe, abubuwan amfanin tantamin BC a ƙarƙashin inuwa sun haɗa da:

• Ƙananan asarar samar da wutar lantarki a ƙarƙashin inuwa ƙarami, kafin diode na waje ya kunna;

• Ƙananan ƙarfin wutar lantarki na gida;

• Ƙananan zafin wuri mai zafi;

• Mafi girman iyakar aminci na module.

Abin da Wannan ke Nufi ga Aikace-aikacen Module

Menene wannan ke nufi ga aikace-aikacen module?

A amfani na gaske, inuwa sau da yawa ba za a iya guje wa gaba ɗaya ba.

Musamman a yanayin rarraba, kamar:

• Rufin gidaje;

• Rufin kasuwanci da masana'antu;

• Balcony PV;

• BIPV;

• Hawan fuska da yawa;

• Wuraren da gine-gine masu rikitarwa suka kewaye.

A cikin waɗannan aikace-aikace, modules na iya fuskantar inuwa na gida akai-akai.

Idan tantanin halitta yana da kyakkyawan juriyar inuwa da ƙananan zafin wuri mai zafi, yana nufin:

• Mafi kyawun amincin module: ƙananan zafin wuri mai zafi yana rage tsufa na rufewa, lalacewar bayan fage, damuwa na gilashin gida, da haɗarin lantarki.

• Ingantacciyar dogaro na dogon lokaci: zafin gida mai girma yana hanzarta tsufan kayan aiki. Mafi raunin wuri mai zafi, mafi kwanciyar hankali na tsarin a tsawon lokaci.

• Ƙarin sarrafa asarar samarwa: idan ba za a iya guje wa inuwa ta gida ba, tsarin BC zai iya rage wani ɓangare na asarar wutar lantarki.

• Tsarin da ya fi dacewa.

Tsarin BC sun fi dacewa da rufin hadaddun, wuraren shigarwa da aka rarraba, da yanayin inuwa da yawa.

Takaitawa

Takaitawa

Kwayoyin BC suna da kyakkyawan juriyar inuwa da ƙananan zafin wuri mai zafi, ba saboda 'ba su shafar inuwa' ba, amma saboda suna da fa'idodi a tsari da halayen juyawa baya.

Ƙarƙashin inuwa, kwayoyin yau da kullun na iya ganin raguwar juyawa ta mayar da hankali a wuraren lahani na gida, yana haifar da babban ƙarfin wutar lantarki na gida da babban zafin wuri mai zafi.

Tsarin haɗin PN na baya na kwayar BC yana aiki kamar matsewar juyawa da aka rarraba. Ƙarƙashin inuwa, yana iya samar da gudanarwa ta baya a ƙananan ƙarfin juyawa kuma ya bazu wutar lantarki ta baya daidai, wanda ke rage ƙarfin wuri mai zafi da zafin wuri mai zafi.

Amma ka tuna, ƙwayoyin BC ba su da cikakkiyar kariya daga inuwa. Lokacin da wurin da aka yi inuwa ya yi girma da yawa, ƙwayoyi da yawa suna cikin inuwa gaba ɗaya, kuma ƙarfin substring ɗin ya yi ƙasa da isasshen ƙarfi, bypass diode na waje har yanzu yana kunna. A wannan lokacin, fitowar substring ɗin da aka yi bypass ɗin ta ragu sosai.

Don haka hanya mafi inganci don faɗi shi:

fa'idar ƙwayar BC ba ita ce kawar da tasirin inuwa ba, amma don sanya wannan tasirin ya zama mai iya sarrafawa. A ƙarƙashin inuwa ƙarami, yana rage asarar wutar lantarki; a ƙarƙashin inuwa mai nauyi, yana rage haɗarin hot spot.

Wannan shine ainihin dalilin da ya sa ƙwayoyin BC ke da fa'ida a wuraren inuwa masu rikitarwa.

Ra'ayin Ooitech

Abin sha'awa a nan shi ne cewa juriyar inuwa ba kawai zaɓin ƙirar ƙwayar ba ce, har ma yana dogara da yadda wannan tsarin interdigitated back pattern ɗin ake sake haifarwa a kowane ƙwayar a cikin layi. Ƙananan canje-canje a cikin metallization, girman tazara, ko ingancin passivation na iya canza halayen reverse breakdown ɗin da muka bayyana, wanda shine dalilin da ya sa sarrafa tsari a kan layin samar da BC ke da mahimmanci kamar girke-girken ƙwayar. Ooitech ta shafe shekaru tana gina layukan samar da module na turnkey don TOPCon, HPBC, ABC da sauran nau'ikan module na BC, don haka muna kallon waɗannan tagogin tsari na back-contact sosai. Idan kana son ganin yadda waɗannan module ɗin ake ginawa a filin masana'anta, tashar mu ta YouTube a www.youtube.com/ooitech yana da hotunan layin samarwa na gaske da yawa da ya kamata a duba.