電池組裝是先并聯好還是線串聯好?
鋰離子電池要想能在電壓大小,容量大小和電流大小能滿足一定的實際應用需求,就必須通過多顆電芯進行串(chuan)(chuan)聯和(he)并聯的(de)(de)方式來達到相(xiang)應的(de)(de)需求,而(er)在這個電池(chi)組裝的(de)(de)過程中(zhong),是先并聯好呢?還是線串(chuan)(chuan)聯好?
在(zai)國民(min)經濟中的(de)(de)應用(yong)越來(lai)越廣泛,但其功(gong)率和(he)能量(liang)是不(bu)可(ke)兼(jian)容(rong)的(de)(de)一對性(xing)(xing)能。在(zai)實際(ji)設計中,往(wang)往(wang)需要(yao)用(yong)戶在(zai)電(dian)池的(de)(de)功(gong)率與能量(liang)之(zhi)間(jian)進行取舍和(he)平衡,而電(dian)池設計者又(you)左右(you)為(wei)難。另外,大(da)(da)型組(zu)(zu)合(he)(he)電(dian)池組(zu)(zu)需要(yao)多(duo)串并來(lai)實現,根據往(wang)常的(de)(de)理(li)論,參與組(zu)(zu)合(he)(he)的(de)(de)單(dan)體(ti)電(dian)池性(xing)(xing)能一致性(xing)(xing)要(yao)控制在(zai)較(jiao)窄(zhai)的(de)(de)范圍,否則會(hui)因為(wei)電(dian)池組(zu)(zu)中各單(dan)體(ti)電(dian)池之(zhi)間(jian)的(de)(de)性(xing)(xing)能差(cha)異嚴重影響電(dian)池組(zu)(zu)的(de)(de)循(xun)環壽命(ming)。因此電(dian)池組(zu)(zu)需求單(dan)體(ti)越多(duo),匹(pi)配(pei)的(de)(de)難度就越大(da)(da),不(bu)能匹(pi)配(pei)的(de)(de)電(dian)池就越多(duo),會(hui)造成極大(da)(da)的(de)(de)浪費。為(wei)了解(jie)決(jue)(jue)以(yi)上問題(ti),本文在(zai)理(li)論分析的(de)(de)基礎上做了大(da)(da)膽的(de)(de)突破,將(jiang)不(bu)同(tong)類型的(de)(de)電(dian)池按照一定規律進行組(zu)(zu)合(he)(he),試(shi)驗(yan)證(zheng)明(ming)這種電(dian)池組(zu)(zu)合(he)(he)方式不(bu)僅能解(jie)決(jue)(jue)高功(gong)率和(he)高能量(liang)的(de)(de)矛盾問題(ti),同(tong)時(shi)也提出了減(jian)緩(huan)大(da)(da)規模(mo)電(dian)池組(zu)(zu)合(he)(he)壓(ya)力的(de)(de)具體(ti)方法(fa)。


上(shang)圖為(wei)(wei)先(xian)串后并的(de)組合電(dian)(dian)池組示意(yi)圖,其中:Bmn為(wei)(wei)第m并第n 串電(dian)(dian)池;Rm為(wei)(wei)第m并的(de)總串聯電(dian)(dian)阻(zu)(包(bao)含電(dian)(dian)池內阻(zu)和線路接觸電(dian)(dian)阻(zu));Im為(wei)(wei)第m并的(de)電(dian)(dian)流(liu);Ip為(wei)(wei)電(dian)(dian)池組總輸出電(dian)(dian)流(liu);Vm為(wei)(wei)第m 并的(de)總串聯電(dian)(dian)壓;Vp為(wei)(wei)并聯后的(de)總輸出電(dian)(dian)壓。從圖1可知(zhi)Ip=I1+I2+I3+……+Im
組(zu)(zu)合電(dian)池(chi)選取同一(yi)電(dian)壓平臺(電(dian)池(chi)的(de)正負極(ji)材料(liao)一(yi)致(zhi))的(de)電(dian)池(chi),即V1=V2=……=Vm=V;每(mei)(mei)并的(de)串(chuan)聯電(dian)池(chi)要求按(an)照(zhao)容(rong)量、內阻等參數(shu)進行配組(zu)(zu),即Bm1、Bm2、……Bmn,要求性能匹(pi)配一(yi)致(zhi),每(mei)(mei)并之間(即B1n、B2n、……Bmn之間)不要求電(dian)參數(shu)一(yi)致(zhi)。
Im=(Vm-Vp)/Rm,在(zai)放電(dian)(dian)(dian)過程(cheng),每一(yi)并(bing)電(dian)(dian)(dian)池串(chuan)的(de)電(dian)(dian)(dian)流(liu)和(he)本并(bing)電(dian)(dian)(dian)路的(de)電(dian)(dian)(dian)阻(zu)值成反比(bi),也就(jiu)是說,在(zai)放電(dian)(dian)(dian)過程(cheng)中,由(you)于各并(bing)電(dian)(dian)(dian)池串(chuan)的(de)串(chuan)聯電(dian)(dian)(dian)阻(zu)不同(tong),流(liu)經(jing)此并(bing)電(dian)(dian)(dian)池串(chuan)的(de)電(dian)(dian)(dian)流(liu)就(jiu)不同(tong),即I1、I2、……Im是不相同(tong)的(de),而且在(zai)放電(dian)(dian)(dian)過程(cheng)中不斷變化(hua),但總(zong)體(ti)保(bao)持Ip=I1+I2+I3+…+In的(de)動態平衡。
Vp=Vm-ImRm,如果在放(fang)電(dian)(dian)(dian)(dian)過(guo)程中某一(yi)并(bing)電(dian)(dian)(dian)(dian)池(chi)串(chuan)(chuan)的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)(Vm)變低(和(he)其他并(bing)串(chuan)(chuan)聯電(dian)(dian)(dian)(dian)池(chi)串(chuan)(chuan)電(dian)(dian)(dian)(dian)壓(ya)比),因為Im=(Vm-Vp)/Rm,電(dian)(dian)(dian)(dian)池(chi)組(zu)就(jiu)會(hui)(hui)自(zi)動(dong)通過(guo)減少(shao)此(ci)并(bing)電(dian)(dian)(dian)(dian)池(chi)串(chuan)(chuan)的(de)(de)電(dian)(dian)(dian)(dian)流,這樣就(jiu)會(hui)(hui)抬(tai)高此(ci)并(bing)電(dian)(dian)(dian)(dian)池(chi)串(chuan)(chuan)的(de)(de)總電(dian)(dian)(dian)(dian)壓(ya)(Vm),因此(ci)電(dian)(dian)(dian)(dian)池(chi)組(zu)處在一(yi)個動(dong)態(tai)平(ping)衡的(de)(de)放(fang)電(dian)(dian)(dian)(dian)狀(zhuang)態(tai),使電(dian)(dian)(dian)(dian)池(chi)組(zu)保(bao)持(chi)一(yi)定的(de)(de)平(ping)衡電(dian)(dian)(dian)(dian)壓(ya)(Vp),這樣電(dian)(dian)(dian)(dian)池(chi)組(zu)在電(dian)(dian)(dian)(dian)壓(ya)動(dong)態(tai)平(ping)衡的(de)(de)過(guo)程中,使每一(yi)并(bing)電(dian)(dian)(dian)(dian)池(chi)串(chuan)(chuan)都能放(fang)出各自(zi)的(de)(de)容量,而不會(hui)(hui)過(guo)放(fang)。
充(chong)(chong)電(dian)過程相(xiang)反,原理相(xiang)似,由于充(chong)(chong)電(dian)電(dian)壓(ya)的(de)動(dong)態平衡,使得(de)每一串電(dian)池(chi)都(dou)能充(chong)(chong)進各自的(de)容量,而不會過充(chong)(chong)。


先并聯后串(chuan)聯的(de)連接方式(shi)如上(shang)圖(tu) 所(suo)示(shi),由于(yu)B11、B12……B1n是通過(guo)配組(zu)篩(shai)選(xuan)的(de),其電性能可以視為是一致的(de),即從電性能看,B11、B12……B1n相同,同樣Bm1、Bm2……Bmn
相同,所以并(bing)聯(lian)后,B并(bing)1=B并(bing)2=……=B并(bing)n(其中B并(bing)n就是(shi)B1n、B2n……Bmn的并(bing)聯(lian)結果)。那么,整(zheng)組(zu)電(dian)池就相當于篩選配組(zu)后的B并(bing)1、B并(bing)2……B并(bing)n串(chuan)聯(lian),充(chong)放電(dian)是(shi)沒有問題的。而Bm1、Bm2……Bmn并(bing)聯(lian)和圖1 分析相近,由上面的分析可(ke)知,先并(bing)聯(lian)后串(chuan)聯(lian)的電(dian)池組(zu)能正常充(chong)放電(dian),這(zhe)里不(bu)再贅述。
通過以上理論分析,可以得出結論,如果滿足條件:組成電池組的(de)(de)所有電(dian)(dian)池(chi)的(de)(de)電(dian)(dian)壓平臺一致(zhi)(電(dian)(dian)池(chi)的(de)(de)正、負極(ji)材(cai)料一致(zhi)),串(chuan)聯(lian)方(fang)向相對應(ying)的(de)(de)單體(ti)電(dian)(dian)池(chi)經(jing)過嚴格的(de)(de)配組(zu)篩選(保持內阻、容量等一致(zhi)),那么單體(ti)電(dian)(dian)池(chi)無論(lun)是(shi)先(xian)串(chuan)后并,還是(shi)先(xian)并后串(chuan)進行組(zu)合,組(zu)成的(de)(de)電(dian)(dian)池(chi)組(zu)可以(yi)正常地充放電(dian)(dian),不(bu)會影響電(dian)(dian)池(chi)組(zu)的(de)(de)循環壽(shou)命。





