1.蓄電池的特點

目前(qian)常用的四(si)種(zhong)化(hua)學電池(chi)是鉛酸(suan)電池(chi)（PbSO4）、鋰(li)離(li)子電池(chi)（Li＋）、鎳鉻電池(chi)（NiCd）和鎳氫電池(chi)（NiMH）。由于環保問(wen)題(ti)和對電池(chi)的要求(qiu)越(yue)來(lai)越(yue)高等綜合因素(su)，推動了新電池(chi)技術的發(fa)展。

1．1 鎳(nie)鉻(ge)電(dian)池(chi)和鎳(nie)氫(qing)電(dian)池(chi)

鎳鉻(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)容(rong)(rong)量(liang)(liang)比鎳氫(qing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)或鋰離(li)子電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)低，具有低阻(zu)抗特性，對于(yu)需(xu)要(yao)短(duan)時(shi)(shi)(shi)(shi)間大電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)(de)應用(yong)(yong)(yong)(yong)場(chang)(chang)合很具吸(xi)引力(li)。但(dan)鎳鉻(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)如果未經充(chong)(chong)(chong)(chong)分放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)又進(jin)行(xing)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，或者長(chang)時(shi)(shi)(shi)(shi)間處(chu)于(yu)小(xiao)(xiao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀(zhuang)態(tai)，就(jiu)(jiu)會(hui)(hui)產(chan)生枝狀(zhuang)晶體(ti)，引起“記憶(yi)效(xiao)(xiao)應”，從而導(dao)(dao)致電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)內阻(zu)變大，容(rong)(rong)量(liang)(liang)變小(xiao)(xiao)，縮短(duan)了電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)壽命(ming)。如果在(zai)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)前進(jin)行(xing)完全(quan)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，使每節電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓降到1．0V左右，就(jiu)(jiu)能消除引起“記憶(yi)效(xiao)(xiao)應”的(de)(de)(de)(de)枝狀(zhuang)晶體(ti)，恢(hui)復電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)性能。鎳氫(qing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)具有較高(gao)的(de)(de)(de)(de)容(rong)(rong)量(liang)(liang)，但(dan)其(qi)自放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)率(lv)(lv)(lv)也較高(gao)，約為(wei)(wei)鎳鉻(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)二倍(bei)。在(zai)初始階段其(qi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)率(lv)(lv)(lv)尤高(gao)（每天放(fang)(fang)掉1％）。所以(yi)鎳氫(qing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)不(bu)(bu)(bu)宜(yi)用(yong)(yong)(yong)(yong)于(yu)需(xu)要(yao)長(chang)時(shi)(shi)(shi)(shi)間保持電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)容(rong)(rong)量(liang)(liang)的(de)(de)(de)(de)場(chang)(chang)合。就(jiu)(jiu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)而言，兩(liang)種電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)非常相似，都是(shi)以(yi)恒流(liu)的(de)(de)(de)(de)方式(shi)進(jin)行(xing)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，可采用(yong)(yong)(yong)(yong)快速(su)(su)(su)(su)、標(biao)準或者涓(juan)流(liu)的(de)(de)(de)(de)方式(shi)進(jin)行(xing)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。它(ta)們都能以(yi)超過2C（C為(wei)(wei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)容(rong)(rong)量(liang)(liang)，單位為(wei)(wei)安培）的(de)(de)(de)(de)速(su)(su)(su)(su)率(lv)(lv)(lv)進(jin)行(xing)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)（但(dan)一般采用(yong)(yong)(yong)(yong)C／2速(su)(su)(su)(su)率(lv)(lv)(lv)）。由于(yu)存在(zai)內部損耗，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)效(xiao)(xiao)率(lv)(lv)(lv)一般小(xiao)(xiao)于(yu)100％，所以(yi)，在(zai)采用(yong)(yong)(yong)(yong)C／2的(de)(de)(de)(de)速(su)(su)(su)(su)率(lv)(lv)(lv)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)(shi)(shi)，通常需(xu)要(yao)兩(liang)個(ge)多(duo)小(xiao)(xiao)時(shi)(shi)(shi)(shi)才能把電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)充(chong)(chong)(chong)(chong)滿。充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)過程中的(de)(de)(de)(de)損耗隨著充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)速(su)(su)(su)(su)率(lv)(lv)(lv)和(he)(he)(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)不(bu)(bu)(bu)同(tong)而不(bu)(bu)(bu)同(tong)。在(zai)恒流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓會(hui)(hui)緩慢(man)達到峰值(zhi)（ΔV／Δt變為(wei)(wei)0），鎳氫(qing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)需(xu)在(zai)這(zhe)個(ge)峰值(zhi)點(dian)終止(zhi)快速(su)(su)(su)(su)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，鎳鉻(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)須在(zai)峰值(zhi)點(dian)后當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓開始下(xia)降時(shi)(shi)(shi)(shi)（ΔV／Δt變為(wei)(wei)負(fu)）即終止(zhi)快速(su)(su)(su)(su)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，否則會(hui)(hui)導(dao)(dao)致電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)內壓力(li)和(he)(he)(he)溫(wen)度(du)(du)上升(sheng)而損壞電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)。當充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)速(su)(su)(su)(su)率(lv)(lv)(lv)大于(yu)C／2時(shi)(shi)(shi)(shi)，則要(yao)監測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓和(he)(he)(he)溫(wen)度(du)(du)，因為(wei)(wei)當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)快充(chong)(chong)(chong)(chong)滿時(shi)(shi)(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)溫(wen)度(du)(du)會(hui)(hui)急劇(ju)上升(sheng)。對于(yu)鎳鉻(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)和(he)(he)(he)鎳氫(qing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)，還可以(yi)采用(yong)(yong)(yong)(yong)比較簡便的(de)(de)(de)(de)涓(juan)流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，這(zhe)時(shi)(shi)(shi)(shi)只(zhi)會(hui)(hui)造成極小(xiao)(xiao)的(de)(de)(de)(de)溫(wen)升(sheng)，不(bu)(bu)(bu)會(hui)(hui)損壞電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)，也就(jiu)(jiu)無需(xu)終止(zhi)涓(juan)流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)或者監測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓。允許的(de)(de)(de)(de)最大涓(juan)流(liu)隨著電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)類(lei)型和(he)(he)(he)環境溫(wen)度(du)(du)的(de)(de)(de)(de)不(bu)(bu)(bu)同(tong)而不(bu)(bu)(bu)同(tong)，典型條件下(xia)C／15較為(wei)(wei)安全(quan)。

1．2 鋰離子電池

過(guo)(guo)(guo)去幾(ji)年中，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)技術(shu)領域最(zui)(zui)突出(chu)的(de)(de)創新就是鋰離(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)。相(xiang)對于(yu)鎳基電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)而言(yan)，鋰離(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)具有(you)更(geng)高的(de)(de)容(rong)量(liang)。從容(rong)量(liang)／體積比(bi)來(lai)衡量(liang)，鋰離(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)比(bi)鎳氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)高出(chu)10％～30％，從容(rong)量(liang)／質(zhi)量(liang)比(bi)來(lai)看，鋰離(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)比(bi)鎳氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)高出(chu)近(jin)兩(liang)倍(bei)。但(dan)鋰離(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)對于(yu)過(guo)(guo)(guo)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)和欠(qian)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)很(hen)敏感(gan)。要達到(dao)最(zui)(zui)大(da)容(rong)量(liang)就必須(xu)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)到(dao)最(zui)(zui)高電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，而過(guo)(guo)(guo)高的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和過(guo)(guo)(guo)大(da)的(de)(de)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)或放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)又會造成電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)永(yong)久性損(sun)壞。如果多(duo)次放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)至(zhi)過(guo)(guo)(guo)低的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)則會造成容(rong)量(liang)損(sun)失(shi)，所(suo)以，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)和放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時都(dou)須(xu)限制其電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)，以保(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)不受損(sun)壞。鋰離(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)方式不同(tong)于(yu)鎳基材料的(de)(de)化學電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時需用一(yi)個電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)―電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)源(yuan)來(lai)進行充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。為了(le)獲得(de)最(zui)(zui)大(da)的(de)(de)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)而又不損(sun)壞電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)，須(xu)使(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)持(chi)在1％的(de)(de)精度內。快速充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)開(kai)始時，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)比(bi)較低，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)即(ji)為電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)極限。隨著充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)進行，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)緩慢(man)上升，最(zui)(zui)終(zhong)當(dang)每節電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)達到(dao)浮空電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya) 4．2V時，此時即(ji)可終(zhong)止(zhi)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。

2　總體設計

2．1 充電(dian)器(qi)芯(xin)片MAX846A

MAX846A是一種16腳QSOP封裝的通用型充電控制芯片，可以單獨構成鋰離子電池充電器，也可以在單片機的控制下對鋰離子電池和鎳基電池進行充(chong)電(dian)(dian)(dian)(dian)(dian)。圖(tu)(tu)1為其QSOP封(feng)裝的(de)管腳(jiao)圖(tu)(tu)。圖(tu)(tu)中(zhong)，1腳(jiao)DCIN和(he)(he)4腳(jiao)GND及(ji)15腳(jiao)PGND分(fen)(fen)別(bie)為電(dian)(dian)(dian)(dian)(dian)源(yuan)和(he)(he)地端(duan)(duan)。2腳(jiao)VL端(duan)(duan)可提供3．3V，1％的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)基準。3腳(jiao)CCI和(he)(he)5腳(jiao)CCV分(fen)(fen)別(bie)為電(dian)(dian)(dian)(dian)(dian)流(liu)和(he)(he)電(dian)(dian)(dian)(dian)(dian)壓(ya)調節(jie)回(hui)路(lu)(lu)補償端(duan)(duan)。7腳(jiao)ISET和(he)(he)6腳(jiao)VSET分(fen)(fen)別(bie)為充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)和(he)(he)電(dian)(dian)(dian)(dian)(dian)壓(ya)回(hui)路(lu)(lu)設定端(duan)(duan)。8腳(jiao)OFFV為電(dian)(dian)(dian)(dian)(dian)壓(ya)調節(jie)回(hui)路(lu)(lu)控制端(duan)(duan)，對于鎳基電(dian)(dian)(dian)(dian)(dian)池(chi)置為高(gao)電(dian)(dian)(dian)(dian)(dian)平(ping)(ping)。當VL端(duan)(duan)電(dian)(dian)(dian)(dian)(dian)壓(ya)低于3V時(shi)，9腳(jiao)PWROK輸(shu)出(chu)低電(dian)(dian)(dian)(dian)(dian)平(ping)(ping)，可給MCU提供復位信號(hao)。10腳(jiao)CELL2為鋰離子電(dian)(dian)(dian)(dian)(dian)池(chi)選擇端(duan)(duan)，低電(dian)(dian)(dian)(dian)(dian)平(ping)(ping)時(shi)為一(yi)節(jie)，高(gao)電(dian)(dian)(dian)(dian)(dian)平(ping)(ping)時(shi)為兩節(jie)。11腳(jiao)ON為充(chong)電(dian)(dian)(dian)(dian)(dian)控制端(duan)(duan)，低電(dian)(dian)(dian)(dian)(dian)平(ping)(ping)時(shi)停止充(chong)電(dian)(dian)(dian)(dian)(dian)。12腳(jiao)BATT端(duan)(duan)接(jie)電(dian)(dian)(dian)(dian)(dian)池(chi)正極(ji)。13腳(jiao)CS＋和(he)(he)14腳(jiao)CS－為內部電(dian)(dian)(dian)(dian)(dian)流(liu)檢測放大器(qi)輸(shu)入端(duan)(duan)。16腳(jiao)DRV為外部調節(jie)晶體管驅動(dong)端(duan)(duan)。

2．2 硬件設計

充電器硬件結構圖如圖2所示。整個系統以MCU為核心構成，包括電源電路、調節電路、充電與放電電路、鍵盤與顯示電路及報警電路等環節。
 

MCU選(xuan)(xuan)用(yong)AT89C51，片(pian)內帶4K的EEPROM，這樣就無(wu)需擴(kuo)展程序存儲器(qi)，簡化(hua)了電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)設計(ji)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源回路(lu)中(zhong)，220V的交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)經變壓(ya)器(qi)降為 12V，經過(guo)整(zheng)流(liu)(liu)濾(lv)波變為14V左(zuo)右，作(zuo)為MAX846A的充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源，另外經7805穩壓(ya)后作(zuo)為其他(ta)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)單元的工(gong)作(zuo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源。調節電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)主要(yao)由A／D和D／A構成(cheng)，用(yong)于檢測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和溫度及設置(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的浮空電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)。充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)以MAX846A為中(zhong)心，完成(cheng)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)過(guo)程。充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)過(guo)程的啟停及充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)的選(xuan)(xuan)擇由單片(pian)機對MAX846A進行控制來實現。放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)用(yong)以消除(chu)鎳鉻電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的“記憶效(xiao)應”。報警電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)在系(xi)統工(gong)作(zuo)時給出必要(yao)的聲音提示(shi)。鍵(jian)盤和顯(xian)示(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)用(yong)于設置(zhi)和顯(xian)示(shi)相(xiang)關的參數。

2．3 充電器的功能設計
　　系統工作時通過鍵盤選擇電池類型和充電方式，并由一位數碼管顯示。具體方式如下所示：
    （1）鎳鉻電池全電流快速充電方式
    （2）鎳鉻電池標準充電方式
    （3）鎳氫電池全電流快速充電方式
    （4）鎳氫電池標準充電方式
    （5）鋰離子電池快速充電方式
    （6）鋰離子(zi)電池標準充(chong)電方式

系統啟動時先進行初始化，隨后檢查電池是否開路。如開路則LED顯示0并蜂鳴提示，如正常則按照設置的充電方式進行充電。在對鎳鉻電池充電時，首先檢測電池是否已充分放電，如單節電池電壓在1．0V以上，則先進行完全放電以消除其“記憶效應”。對于鎳基電池，無論采用哪一種充電方式，在充電結束后自動進入涓流充電方式，以補償電池的自放電。鋰離子電池的自放電率最低，所以無需涓流充電。在快速充電時，鎳鉻電池采用負斜率終止充電（ΔV／Δt小于0），鎳氫電池采用(yong)零斜率(lv)終(zhong)止(zhi)(zhi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)（ΔV／Δt等于0），鋰離子電(dian)(dian)(dian)(dian)(dian)(dian)池采用(yong)頂(ding)端截止(zhi)(zhi)。另外，在快速充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，如電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)壓或者(zhe)溫度(du)超限以及(ji)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)間超過三小時(shi)，系統都將停止(zhi)(zhi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)并(bing)蜂鳴提示。充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)結束(shu)時(shi)數碼管顯(xian)示P并(bing)蜂鳴提示。出于對電(dian)(dian)(dian)(dian)(dian)(dian)池壽命(ming)的考慮，在多(duo)次(ci)快充(chong)后(hou)，建議采用(yong)標準(zhun)方式充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)一次(ci)。

2．4 軟件設計

系統的(de)(de)軟件設計采用模(mo)(mo)塊(kuai)(kuai)(kuai)式結(jie)構，主要由初始化程(cheng)序、充(chong)(chong)(chong)電(dian)(dian)方式設置模(mo)(mo)塊(kuai)(kuai)(kuai)、預處理模(mo)(mo)塊(kuai)(kuai)(kuai)、A／D轉換模(mo)(mo)塊(kuai)(kuai)(kuai)、D／A轉換模(mo)(mo)塊(kuai)(kuai)(kuai)、定(ding)時(shi)(shi)模(mo)(mo)塊(kuai)(kuai)(kuai)和(he)(he)顯示(shi)模(mo)(mo)塊(kuai)(kuai)(kuai)等(deng)部分組成。其中，充(chong)(chong)(chong)電(dian)(dian)方式設置模(mo)(mo)塊(kuai)(kuai)(kuai)用于(yu)設置電(dian)(dian)池類型和(he)(he)充(chong)(chong)(chong)電(dian)(dian)方式；A／D轉換模(mo)(mo)塊(kuai)(kuai)(kuai)用于(yu)檢測(ce)電(dian)(dian)池的(de)(de)電(dian)(dian)壓和(he)(he)溫度，以確定(ding)是否(fou)終止充(chong)(chong)(chong)電(dian)(dian)過程(cheng)；D／A轉換模(mo)(mo)塊(kuai)(kuai)(kuai)用于(yu)設置充(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)和(he)(he)電(dian)(dian)壓；定(ding)時(shi)(shi)模(mo)(mo)塊(kuai)(kuai)(kuai)用于(yu)確定(ding)零斜(xie)(xie)率或(huo)負斜(xie)(xie)率檢測(ce)的(de)(de)頻度以及快充(chong)(chong)(chong)的(de)(de)時(shi)(shi)間監測(ce)，斜(xie)(xie)率檢測(ce)為(wei)每分鐘一次，快充(chong)(chong)(chong)的(de)(de)時(shi)(shi)間限為(wei)三小時(shi)(shi)。系統程(cheng)序的(de)(de)流(liu)程(cheng)圖如圖3所示(shi)。

3　結束語

采用單片機和充電集成電路進行充電器設計，不但能夠實(shi)現(xian)對一般(ban)的(de)(de)蓄電(dian)(dian)(dian)池進行充電(dian)(dian)(dian)，而(er)且(qie)還能夠實(shi)現(xian)相應的(de)(de)過壓(ya)和溫(wen)度保護，從而(er)可以(yi)充分發揮蓄電(dian)(dian)(dian)池的(de)(de)性能，延長電(dian)(dian)(dian)池的(de)(de)使(shi)用壽命，并避免簡(jian)易充電(dian)(dian)(dian)器在充電(dian)(dian)(dian)時可能對電(dian)(dian)(dian)池造成損(sun)害的(de)(de)情況發生，具有(you)一定的(de)(de)智能功能，符合目前(qian)的(de)(de)環境保護潮(chao)流。