儲能系統電池維護方法與專用充電器
目(mu)前電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)成(cheng)組的(de)(de)(de)(de)最(zui)大(da)困難是(shi)大(da)容(rong)(rong)量電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)(de)(de)(de)一(yi)致(zhi)性問題,也(ye)就是(shi)對(dui)于某(mou)批次的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)來說(shuo),容(rong)(rong)量相(xiang)(xiang)等(deng)(deng)(deng)對(dui)應的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)相(xiang)(xiang)等(deng)(deng)(deng),或者電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)相(xiang)(xiang)等(deng)(deng)(deng)對(dui)應容(rong)(rong)量相(xiang)(xiang)等(deng)(deng)(deng)。電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)單體(ti)單獨使用時(shi),對(dui)一(yi)致(zhi)性要(yao)(yao)求并不高,隨著電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)應用范圍的(de)(de)(de)(de)擴大(da),單體(ti)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)趨(qu)向(xiang)大(da)容(rong)(rong)量高電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)發展(zhan),對(dui)于性能源(yuan)(yuan)設備來說(shuo),單體(ti)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)提(ti)供的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)與(yu)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)是(shi)遠(yuan)遠(yuan)不夠的(de)(de)(de)(de),所(suo)以電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)成(cheng)組應用是(shi)新能源(yuan)(yuan)應用與(yu)發展(zhan)的(de)(de)(de)(de)必然(ran)趨(qu)勢(shi),但(dan)是(shi)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)成(cheng)組時(shi),又(you)受(shou)(shou)到電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)一(yi)致(zhi)性的(de)(de)(de)(de)牽制,電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)(de)(de)(de)一(yi)致(zhi)性不好,不僅受(shou)(shou)生(sheng)產制造過(guo)程(cheng)的(de)(de)(de)(de)影響,而且在工(gong)(gong)程(cheng)應用不當也(ye)會加劇電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)一(yi)致(zhi)性變差,所(suo)以要(yao)(yao)求工(gong)(gong)程(cheng)人員想辦法(fa)對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)進行維護,盡量減小(xiao)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)在容(rong)(rong)量極差、單體(ti)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)(de)(de)極差,保持(chi)系(xi)統長期穩(wen)定高效(xiao)的(de)(de)(de)(de)工(gong)(gong)作。
以磷酸亞鐵鋰離子電池為例,探討成組電池系統維護方法,增加成組電池的循環次數,延長電池系統的使用壽命。
在實際(ji)工程應(ying)用中,電(dian)(dian)池(chi)(chi)(chi)成組(zu)經(jing)常發生,成組(zu)前電(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)一(yi)(yi)致性最起碼(ma)能夠讓人接受,經(jing)過幾百次循環后,在電(dian)(dian)池(chi)(chi)(chi)組(zu)中會發現電(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)靜態(tai)電(dian)(dian)壓明(ming)顯不一(yi)(yi)致,這同時說明(ming)電(dian)(dian)池(chi)(chi)(chi)容(rong)量也不一(yi)(yi)致,由于沒(mei)有合適的(de)(de)(de)系統(tong)維護方法,使得(de)電(dian)(dian)池(chi)(chi)(chi)系統(tong)不能得(de)到充(chong)分的(de)(de)(de)利用。
部分工程人員就是將該單體電池與電池組一起做一個完整的充放電循環,然后把不一致的電池取下來,再換新電池,新電池的容量、電壓是否與系統匹配,現在的維護工程師們可能都考慮到,但他們總不能把電池廠的化成分容柜為兩塊電池用卡車搬到現場吧.還有的工程人員就是將整個電池包用卡車搬運到工廠重新化成分容,然后再送到現場,這種方法對電動工具,電動自行車等小電池系統還能接受,對大型的電池儲能系統,維護的代價就太高了。
建議采用恒流限壓充電維護法或者定量補充電量維護法對成組電池中的部分單體電池進行修復,這樣維護工作量就大大減少了,在對電池電壓進找平的同時觀察充入電池的電量(充入電量+原有電量=電池當前容量),若電池的容量極差不大,電壓找平后就可以保留在系統中繼續使用。若電池容量極差大,再更換該單體電池。更換單體電池時就采用定量補充電量的方法,只有使新電池的容量與整個系統一致時,才能把新電池裝入系統。
電池模塊箱測試維護接口
若要采用恒流限壓充電維護法或者定量補充電量維護法,首先在電池箱上預留維護測量接口。大多電池模塊是分箱裝配的,而電池箱又是密封的,維修工程師們只能依靠電池管理系統讀回來的數據判斷電池的情況,當要對電池進行維護時,只能開箱測試與維護,所以我建議必須在電池箱上安裝測量維護的接口便于測試維護操作方便。也就是將單體電池串聯的的連接處引出一根能承受0.5倍率電流的導線,數量是N+1根線。同時這也是一根人工測量線。每根線必須用螺絲裝連,并且輸出接口是快速接口。每根線的安全距離必須大于整箱電池串聯電壓的安全距離。每根線必須按照電位從低到高的順序嚴格編號,且在第一根線與最后一根線的接口處必須標注電池箱內電池的極接口要加防塵、防水、防爆保護措施,并且注明非專業人員不能擅自打開的標識。
電池維護充電器
輸入AC180V~AC242V,輸出電壓2.0V~4.5V連續可調,適用于各種材料的鋰電池;輸出電流0A~100A連續可調,適用于1000Ah以下電池組現場維護充電;充電器整機工作效率大于75%。(因為低壓大電流充電器效率不會做的太高)
電路要求功率因數校正、輸入輸出隔離、恒流限壓充電。這是充電機最起碼的工作要求,對于這種低壓大電流的充電器,輸入必須要加APFC,電路拓撲結構最好采用半橋拓撲結構,輸入輸出由變壓器隔離,既可以單獨使用,也可以幾個串聯或并聯使用,以滿足大容量電池模塊或多個單體同時充電。更能節約工程技術人員的維護時間與維護成本,采用高頻同步整流提高充電器工作效率。
測量與顯示要求:輸出電流、電壓實時檢測與顯示、充入電池I*T(電量)實時檢測與顯示、充電進度、被充電池的溫度實時檢測與顯示。在液晶屏上分頁顯示。可手動查閱。
手動功能(neng)設置(zhi)(zhi):充(chong)(chong)(chong)(chong)電(dian)(dian)器分為預置(zhi)(zhi)工(gong)(gong)作(zuo)(zuo)模(mo)式(shi)(shi)和自(zi)動工(gong)(gong)作(zuo)(zuo)模(mo)式(shi)(shi),能(neng)通過(guo)充(chong)(chong)(chong)(chong)電(dian)(dian)器的(de)按鍵手動設置(zhi)(zhi)充(chong)(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)量、電(dian)(dian)流(liu)、電(dian)(dian)壓(ya)、溫度、階段時(shi)間(jian)。在(zai)充(chong)(chong)(chong)(chong)電(dian)(dian)器工(gong)(gong)作(zuo)(zuo)之前(qian)(qian),先設置(zhi)(zhi)恒(heng)流(liu)階段充(chong)(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)值(zhi),恒(heng)流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)過(guo)程的(de)最高電(dian)(dian)壓(ya)值(zhi),當(dang)恒(heng)流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)達到該電(dian)(dian)壓(ya)值(zhi)時(shi),充(chong)(chong)(chong)(chong)電(dian)(dian)器就(jiu)要從(cong)恒(heng)流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)狀(zhuang)態轉換為恒(heng)壓(ya)充(chong)(chong)(chong)(chong)電(dian)(dian)狀(zhuang)態,在(zai)已知電(dian)(dian)池當(dang)前(qian)(qian)容量和應補充(chong)(chong)(chong)(chong)容量的(de)情況(kuang)下,還可(ke)以預先分段設置(zhi)(zhi)充(chong)(chong)(chong)(chong)電(dian)(dian)時(shi)間(jian),將(jiang)設置(zhi)(zhi)的(de)時(shi)間(jian)作(zuo)(zuo)為充(chong)(chong)(chong)(chong)電(dian)(dian)機限制的(de)第(di)二條件(jian)。設置(zhi)(zhi)完成后(hou)按確認鍵保(bao)存(cun)當(dang)前(qian)(qian)設置(zhi)(zhi),按輸出鍵開始(shi)按設置(zhi)(zhi)程序工(gong)(gong)作(zuo)(zuo)。在(zai)自(zi)動模(mo)式(shi)(shi)下,充(chong)(chong)(chong)(chong)電(dian)(dian)器的(de)工(gong)(gong)作(zuo)(zuo)模(mo)式(shi)(shi)按照上次工(gong)(gong)作(zuo)(zuo)設置(zhi)(zhi)的(de)模(mo)式(shi)(shi)工(gong)(gong)作(zuo)(zuo)。
存(cun)儲(chu)(chu)(chu)與(yu)查(cha)詢功能:自動捕獲恒(heng)(heng)流充(chong)電(dian)、恒(heng)(heng)壓充(chong)電(dian)開始與(yu)結束時(shi)的(de)電(dian)池的(de)電(dian)壓、電(dian)流、充(chong)入電(dian)量(liang)(liang)與(yu)電(dian)池內部溫度,并且記錄存(cun)儲(chu)(chu)(chu)電(dian)壓、電(dian)流、溫度、充(chong)入電(dian)量(liang)(liang)。自動捕獲并存(cun)儲(chu)(chu)(chu)充(chong)電(dian)過(guo)程中故障(zhang)時(shi)的(de)電(dian)流、電(dian)壓、溫度與(yu)充(chong)入電(dian)量(liang)(liang)。所(suo)有的(de)數(shu)(shu)據能存(cun)儲(chu)(chu)(chu)可查(cha)詢。(第一版充(chong)電(dian)器存(cun)儲(chu)(chu)(chu)的(de)這些數(shu)(shu)據只供查(cha)詢,不(bu)給(gei)輸(shu)出與(yu)打印)
保護與告警功能:充電器具有輸入過壓欠壓保護、輸入過流保護、輸出過流過壓保護、輸出短路保護、過溫保護、充電已滿保護、充電模式轉換、各保護都設置聲光提示裝置。
該充電器幾何尺寸8U×4U×2U總重量小于3kg便于攜帶。
使用方法:
第一步:將電池組串聯充電至滿容量或者直到BMS保護為止。第二步: 將電池組串聯放電至0容量額定總電壓或者直到BMS保護為止,計算放出電量是否達到額定要求,若未達到要求,對電池組中低于0容量平均電壓的電池模塊進行補充電量,直到該模塊電壓與平均電壓相等。第三步:再將電池組串聯放電至0容量或者直到BMS保護為止,將第一次放出的電量與第二次放出的電量相加,看是否達到額定容量要求,若未達到額定要求,再對電池組中低于0容量平均電壓的電池模塊進行補充電量,到該模塊電壓與平均電壓相等。若還未達到額定要求,再次重復第三步操作直到電池組經過多次累加放電總量等于額定容量或者要求容量。第四步:再將電池組整體做一次滿充滿放循環。看是否達到額定要求電量。若還不能達到要求,說明電池系統容量已經明顯下降,則要更換極差電池。
提前維護:當BMS檢測到電池組中存在個別模塊串聯模塊兩頭電壓(滿充滿放)極差大于20mV時,就可以采用此方法對電壓較低的電池補充一點電量,相當于人為地給電池組系統做一次充放電均衡維護,從而保持電池的一致性并延長電池組的使用壽命。
給新電池充電:更換新電池時,新電池容量與電壓不可能與整組電池容量相匹配,這種情況可以使用該方法,先將新電池用按1C放電,放到0容量,然后在充電器上設置好要充入的電量對新電池充電,當充電器按預置的充電容量充電完成后,這種新電池就可以替換下嚴重極差的電池了。
該方法只能對電(dian)池(chi)(chi)組進行靜態維護,不能在電(dian)池(chi)(chi)組動態下維護。
該電池維護方(fang)法(fa)的適用(yong)范圍
這種維護方法適用于成組電池系統中部分電池因為長期工況不同、檢測方法不同等造成電池的一致性發生差異,最大差異不超過100mV,極差電池數量不超過成組總數的10%。當數量太多,極差很大時,可能系統還存在別的問題,要先排除檢查系統的其他故障。比如安裝、工藝、功率回路、控制回路以及單體電池本身等。
本充電器雖然是以磷酸亞鐵鋰電池為基礎設計的,但該充電器與對電池的維護方法也適用于其他正極材料的鋰離子(因為鋰離子電池充放電過程中,有很長時間電壓變化率很小,電壓與容量的關系并不是成固定斜率線性關系)電池維護。
本充電式電池維護方法,主要適用于對串并聯電池組中單體電池與并聯的模塊電池組維護。相當于電壓在安全范圍內的而對電池容量均衡。而不是對電壓均衡,電壓只是充放電過程中一個在安全門檻,人為的規定了一個閾值而已,所以由試樣單體的串并聯電池組中,單體電池電壓不應該作為衡量該組電池的一致性的關鍵參數,而要以容量來衡量電池一致性。“由于池塘本身不一樣,存水的多少不在于水的深淺”。在測試與維護中,一定要考慮電池的容量。
