1.蓄電池的特點

目前常用的(de)(de)四種(zhong)化(hua)學電(dian)池(chi)是鉛酸電(dian)池(chi)（PbSO4）、鋰離子電(dian)池(chi)（Li＋）、鎳鉻電(dian)池(chi)（NiCd）和(he)鎳氫電(dian)池(chi)（NiMH）。由于(yu)環保問題和(he)對(dui)電(dian)池(chi)的(de)(de)要求越來(lai)越高等綜合因素(su)，推(tui)動(dong)了新電(dian)池(chi)技(ji)術(shu)的(de)(de)發展。

1．1 鎳(nie)鉻電池(chi)和鎳(nie)氫電池(chi)

鎳(nie)鉻電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)(de)(de)(de)(de)(de)容(rong)(rong)(rong)量(liang)比鎳(nie)氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)或(huo)鋰(li)離子電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)低，具(ju)有(you)低阻抗特性，對(dui)于(yu)需(xu)要短(duan)時(shi)(shi)(shi)間(jian)(jian)(jian)大(da)(da)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流的(de)(de)(de)(de)(de)(de)(de)(de)應用(yong)場(chang)合很具(ju)吸引(yin)力。但(dan)鎳(nie)鉻電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)如(ru)果未經充(chong)(chong)(chong)分放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)又進行(xing)(xing)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，或(huo)者長(chang)時(shi)(shi)(shi)間(jian)(jian)(jian)處于(yu)小(xiao)(xiao)(xiao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態，就會(hui)產(chan)生(sheng)枝狀晶(jing)體，引(yin)起“記憶效(xiao)應”，從(cong)而導致電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)內(nei)阻變(bian)大(da)(da)，容(rong)(rong)(rong)量(liang)變(bian)小(xiao)(xiao)(xiao)，縮(suo)短(duan)了(le)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)壽(shou)命。如(ru)果在(zai)(zai)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)前進行(xing)(xing)完(wan)全(quan)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，使(shi)每節電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降到1．0V左右，就能消除(chu)引(yin)起“記憶效(xiao)應”的(de)(de)(de)(de)(de)(de)(de)(de)枝狀晶(jing)體，恢復電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)(de)(de)(de)(de)(de)性能。鎳(nie)氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)具(ju)有(you)較高的(de)(de)(de)(de)(de)(de)(de)(de)容(rong)(rong)(rong)量(liang)，但(dan)其自放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)率(lv)(lv)(lv)也較高，約(yue)為(wei)鎳(nie)鉻電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)(de)(de)(de)(de)(de)二(er)倍(bei)。在(zai)(zai)初始階段其放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)率(lv)(lv)(lv)尤高（每天(tian)放(fang)掉1％）。所(suo)以(yi)鎳(nie)氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)不(bu)(bu)宜用(yong)于(yu)需(xu)要長(chang)時(shi)(shi)(shi)間(jian)(jian)(jian)保(bao)持電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)容(rong)(rong)(rong)量(liang)的(de)(de)(de)(de)(de)(de)(de)(de)場(chang)合。就充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)方(fang)式而言，兩(liang)種電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)非(fei)常(chang)相似(si)，都是以(yi)恒流的(de)(de)(de)(de)(de)(de)(de)(de)方(fang)式進行(xing)(xing)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，可(ke)采用(yong)快(kuai)速(su)、標(biao)準(zhun)或(huo)者涓(juan)流的(de)(de)(de)(de)(de)(de)(de)(de)方(fang)式進行(xing)(xing)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。它們都能以(yi)超(chao)過(guo)2C（C為(wei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)容(rong)(rong)(rong)量(liang)，單位為(wei)安培）的(de)(de)(de)(de)(de)(de)(de)(de)速(su)率(lv)(lv)(lv)進行(xing)(xing)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)（但(dan)一(yi)般(ban)(ban)采用(yong)C／2速(su)率(lv)(lv)(lv)）。由于(yu)存在(zai)(zai)內(nei)部損(sun)耗，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)效(xiao)率(lv)(lv)(lv)一(yi)般(ban)(ban)小(xiao)(xiao)(xiao)于(yu)100％，所(suo)以(yi)，在(zai)(zai)采用(yong)C／2的(de)(de)(de)(de)(de)(de)(de)(de)速(su)率(lv)(lv)(lv)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)(shi)，通(tong)常(chang)需(xu)要兩(liang)個(ge)多小(xiao)(xiao)(xiao)時(shi)(shi)(shi)才能把電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)(chong)滿。充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)過(guo)程中的(de)(de)(de)(de)(de)(de)(de)(de)損(sun)耗隨著(zhu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)速(su)率(lv)(lv)(lv)和(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)(de)(de)(de)(de)(de)不(bu)(bu)同(tong)而不(bu)(bu)同(tong)。在(zai)(zai)恒流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)會(hui)緩(huan)慢達到峰值(zhi)（ΔV／Δt變(bian)為(wei)0），鎳(nie)氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)需(xu)在(zai)(zai)這個(ge)峰值(zhi)點終(zhong)止(zhi)(zhi)快(kuai)速(su)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，鎳(nie)鉻電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)(de)(de)(de)(de)(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)須(xu)在(zai)(zai)峰值(zhi)點后(hou)當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)開始下(xia)降時(shi)(shi)(shi)（ΔV／Δt變(bian)為(wei)負）即終(zhong)止(zhi)(zhi)快(kuai)速(su)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，否則會(hui)導致電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)內(nei)壓(ya)(ya)力和(he)溫度上(shang)(shang)升而損(sun)壞電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)。當(dang)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)速(su)率(lv)(lv)(lv)大(da)(da)于(yu)C／2時(shi)(shi)(shi)，則要監測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)和(he)溫度，因為(wei)當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)快(kuai)充(chong)(chong)(chong)滿時(shi)(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)(de)(de)(de)(de)(de)溫度會(hui)急劇(ju)上(shang)(shang)升。對(dui)于(yu)鎳(nie)鉻電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)和(he)鎳(nie)氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)，還可(ke)以(yi)采用(yong)比較簡便的(de)(de)(de)(de)(de)(de)(de)(de)涓(juan)流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，這時(shi)(shi)(shi)只會(hui)造成極小(xiao)(xiao)(xiao)的(de)(de)(de)(de)(de)(de)(de)(de)溫升，不(bu)(bu)會(hui)損(sun)壞電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)，也就無需(xu)終(zhong)止(zhi)(zhi)涓(juan)流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)或(huo)者監測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)。允許的(de)(de)(de)(de)(de)(de)(de)(de)最(zui)大(da)(da)涓(juan)流隨著(zhu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)類型和(he)環境溫度的(de)(de)(de)(de)(de)(de)(de)(de)不(bu)(bu)同(tong)而不(bu)(bu)同(tong)，典型條件下(xia)C／15較為(wei)安全(quan)。

1．2 鋰離子電池

過(guo)(guo)去幾(ji)年中，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)技術領域最(zui)(zui)(zui)突出(chu)的(de)(de)(de)創新就(jiu)是鋰離(li)(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)。相對于(yu)(yu)鎳基(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)而言，鋰離(li)(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)具有(you)更高(gao)的(de)(de)(de)容量(liang)(liang)。從(cong)容量(liang)(liang)／體積比(bi)(bi)來衡(heng)量(liang)(liang)，鋰離(li)(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)比(bi)(bi)鎳氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)高(gao)出(chu)10％～30％，從(cong)容量(liang)(liang)／質量(liang)(liang)比(bi)(bi)來看(kan)，鋰離(li)(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)比(bi)(bi)鎳氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)高(gao)出(chu)近兩倍。但鋰離(li)(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)對于(yu)(yu)過(guo)(guo)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)和(he)欠充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)很(hen)敏感(gan)。要達(da)到(dao)最(zui)(zui)(zui)大容量(liang)(liang)就(jiu)必須(xu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)到(dao)最(zui)(zui)(zui)高(gao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，而過(guo)(guo)高(gao)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)和(he)過(guo)(guo)大的(de)(de)(de)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)或放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)又會(hui)造成電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)永(yong)久性損(sun)壞(huai)。如果多次放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)至過(guo)(guo)低(di)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)則會(hui)造成容量(liang)(liang)損(sun)失，所(suo)以，充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)和(he)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)都須(xu)限制其電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)和(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)，以保(bao)護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)不(bu)受(shou)損(sun)壞(huai)。鋰離(li)(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)不(bu)同于(yu)(yu)鎳基(ji)材(cai)料的(de)(de)(de)化學電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)，充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)需用一個電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)―電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)源來進行(xing)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。為了獲得最(zui)(zui)(zui)大的(de)(de)(de)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)而又不(bu)損(sun)壞(huai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)，須(xu)使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)保(bao)持(chi)在1％的(de)(de)(de)精度內。快速充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)開始時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)比(bi)(bi)較低(di)，充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)即為電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)極限。隨著(zhu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)進行(xing)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)緩(huan)慢(man)上升，最(zui)(zui)(zui)終當每節電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)達(da)到(dao)浮空電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya) 4．2V時(shi)，此時(shi)即可終止充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。

2　總體設計

2．1 充(chong)電(dian)器(qi)芯片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(xing)充(chong)(chong)電(dian)(dian)(dian)(dian)。圖1為(wei)(wei)(wei)其QSOP封裝的(de)管腳(jiao)(jiao)(jiao)(jiao)圖。圖中(zhong)，1腳(jiao)(jiao)(jiao)(jiao)DCIN和(he)4腳(jiao)(jiao)(jiao)(jiao)GND及(ji)15腳(jiao)(jiao)(jiao)(jiao)PGND分別為(wei)(wei)(wei)電(dian)(dian)(dian)(dian)源和(he)地端(duan)(duan)。2腳(jiao)(jiao)(jiao)(jiao)VL端(duan)(duan)可(ke)提供3．3V，1％的(de)電(dian)(dian)(dian)(dian)壓(ya)基準(zhun)。3腳(jiao)(jiao)(jiao)(jiao)CCI和(he)5腳(jiao)(jiao)(jiao)(jiao)CCV分別為(wei)(wei)(wei)電(dian)(dian)(dian)(dian)流(liu)和(he)電(dian)(dian)(dian)(dian)壓(ya)調節回路補償(chang)端(duan)(duan)。7腳(jiao)(jiao)(jiao)(jiao)ISET和(he)6腳(jiao)(jiao)(jiao)(jiao)VSET分別為(wei)(wei)(wei)充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)和(he)電(dian)(dian)(dian)(dian)壓(ya)回路設(she)定端(duan)(duan)。8腳(jiao)(jiao)(jiao)(jiao)OFFV為(wei)(wei)(wei)電(dian)(dian)(dian)(dian)壓(ya)調節回路控制端(duan)(duan)，對于鎳基電(dian)(dian)(dian)(dian)池(chi)置為(wei)(wei)(wei)高電(dian)(dian)(dian)(dian)平(ping)(ping)(ping)。當VL端(duan)(duan)電(dian)(dian)(dian)(dian)壓(ya)低(di)(di)于3V時，9腳(jiao)(jiao)(jiao)(jiao)PWROK輸出低(di)(di)電(dian)(dian)(dian)(dian)平(ping)(ping)(ping)，可(ke)給(gei)MCU提供復位信號。10腳(jiao)(jiao)(jiao)(jiao)CELL2為(wei)(wei)(wei)鋰離子(zi)電(dian)(dian)(dian)(dian)池(chi)選擇端(duan)(duan)，低(di)(di)電(dian)(dian)(dian)(dian)平(ping)(ping)(ping)時為(wei)(wei)(wei)一節，高電(dian)(dian)(dian)(dian)平(ping)(ping)(ping)時為(wei)(wei)(wei)兩節。11腳(jiao)(jiao)(jiao)(jiao)ON為(wei)(wei)(wei)充(chong)(chong)電(dian)(dian)(dian)(dian)控制端(duan)(duan)，低(di)(di)電(dian)(dian)(dian)(dian)平(ping)(ping)(ping)時停止(zhi)充(chong)(chong)電(dian)(dian)(dian)(dian)。12腳(jiao)(jiao)(jiao)(jiao)BATT端(duan)(duan)接(jie)電(dian)(dian)(dian)(dian)池(chi)正極。13腳(jiao)(jiao)(jiao)(jiao)CS＋和(he)14腳(jiao)(jiao)(jiao)(jiao)CS－為(wei)(wei)(wei)內部(bu)(bu)電(dian)(dian)(dian)(dian)流(liu)檢測放(fang)大器輸入端(duan)(duan)。16腳(jiao)(jiao)(jiao)(jiao)DRV為(wei)(wei)(wei)外部(bu)(bu)調節晶體管驅動端(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)用(yong)AT89C51，片內帶4K的(de)(de)(de)EEPROM，這樣就(jiu)無需擴展(zhan)程序存儲器，簡化了電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)設(she)計。電(dian)(dian)(dian)(dian)源回(hui)路(lu)(lu)(lu)(lu)中(zhong)，220V的(de)(de)(de)交流(liu)電(dian)(dian)(dian)(dian)經(jing)變壓(ya)(ya)(ya)器降為(wei)(wei) 12V，經(jing)過(guo)整流(liu)濾(lv)波(bo)變為(wei)(wei)14V左右，作(zuo)為(wei)(wei)MAX846A的(de)(de)(de)充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)源，另外經(jing)7805穩壓(ya)(ya)(ya)后作(zuo)為(wei)(wei)其他(ta)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)單元的(de)(de)(de)工作(zuo)電(dian)(dian)(dian)(dian)源。調節電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)主要由(you)A／D和(he)D／A構成，用(yong)于檢測電(dian)(dian)(dian)(dian)池的(de)(de)(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)和(he)溫度及設(she)置電(dian)(dian)(dian)(dian)池的(de)(de)(de)浮空電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)和(he)充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)。充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)以MAX846A為(wei)(wei)中(zhong)心，完成充(chong)電(dian)(dian)(dian)(dian)過(guo)程。充(chong)電(dian)(dian)(dian)(dian)過(guo)程的(de)(de)(de)啟停及充(chong)電(dian)(dian)(dian)(dian)方(fang)式的(de)(de)(de)選(xuan)擇(ze)由(you)單片機對MAX846A進行控制來實(shi)現。放電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)用(yong)以消除鎳鉻電(dian)(dian)(dian)(dian)池的(de)(de)(de)“記憶(yi)效應(ying)”。報警電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)在系統(tong)工作(zuo)時(shi)給出必要的(de)(de)(de)聲音提示。鍵盤(pan)和(he)顯示電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)用(yong)于設(she)置和(he)顯示相關的(de)(de)(de)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）鋰離子電(dian)池(chi)標準充電(dian)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(cai)(cai)用零斜(xie)率(lv)終止充電(dian)(dian)（ΔV／Δt等于0），鋰離(li)子電(dian)(dian)池采(cai)(cai)用頂端(duan)截止。另外，在(zai)快速充電(dian)(dian)時(shi)(shi)，如電(dian)(dian)池電(dian)(dian)壓或(huo)者溫(wen)度超(chao)限(xian)以及充電(dian)(dian)時(shi)(shi)間(jian)超(chao)過三小(xiao)時(shi)(shi)，系統都將停止充電(dian)(dian)并蜂鳴提示。充電(dian)(dian)結束(shu)時(shi)(shi)數碼(ma)管顯(xian)示P并蜂鳴提示。出于對(dui)電(dian)(dian)池壽(shou)命(ming)的考慮，在(zai)多(duo)次(ci)(ci)快充后，建議(yi)采(cai)(cai)用標準方(fang)式充電(dian)(dian)一次(ci)(ci)。

2．4 軟件設計

系(xi)(xi)統(tong)的(de)軟(ruan)件(jian)設計采用(yong)模塊(kuai)(kuai)(kuai)(kuai)(kuai)式結構，主要由初(chu)始化程序、充(chong)電(dian)(dian)(dian)方式設置模塊(kuai)(kuai)(kuai)(kuai)(kuai)、預處理模塊(kuai)(kuai)(kuai)(kuai)(kuai)、A／D轉(zhuan)換模塊(kuai)(kuai)(kuai)(kuai)(kuai)、D／A轉(zhuan)換模塊(kuai)(kuai)(kuai)(kuai)(kuai)、定(ding)(ding)(ding)時(shi)(shi)模塊(kuai)(kuai)(kuai)(kuai)(kuai)和(he)顯示模塊(kuai)(kuai)(kuai)(kuai)(kuai)等部分組成。其中，充(chong)電(dian)(dian)(dian)方式設置模塊(kuai)(kuai)(kuai)(kuai)(kuai)用(yong)于設置電(dian)(dian)(dian)池(chi)類型和(he)充(chong)電(dian)(dian)(dian)方式；A／D轉(zhuan)換模塊(kuai)(kuai)(kuai)(kuai)(kuai)用(yong)于檢測(ce)電(dian)(dian)(dian)池(chi)的(de)電(dian)(dian)(dian)壓和(he)溫度，以確定(ding)(ding)(ding)是否終止充(chong)電(dian)(dian)(dian)過程；D／A轉(zhuan)換模塊(kuai)(kuai)(kuai)(kuai)(kuai)用(yong)于設置充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流和(he)電(dian)(dian)(dian)壓；定(ding)(ding)(ding)時(shi)(shi)模塊(kuai)(kuai)(kuai)(kuai)(kuai)用(yong)于確定(ding)(ding)(ding)零斜率或(huo)負斜率檢測(ce)的(de)頻度以及快(kuai)(kuai)充(chong)的(de)時(shi)(shi)間(jian)監測(ce)，斜率檢測(ce)為每(mei)分鐘一次，快(kuai)(kuai)充(chong)的(de)時(shi)(shi)間(jian)限為三小(xiao)時(shi)(shi)。系(xi)(xi)統(tong)程序的(de)流程圖(tu)如圖(tu)3所(suo)示。

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(neng)(neng)夠實(shi)現(xian)(xian)對(dui)一(yi)般的(de)蓄電(dian)池(chi)進行充(chong)電(dian)，而且(qie)還能(neng)(neng)夠實(shi)現(xian)(xian)相應(ying)的(de)過壓和溫度保護(hu)(hu)，從(cong)而可(ke)以(yi)充(chong)分(fen)發(fa)揮蓄電(dian)池(chi)的(de)性能(neng)(neng)，延長電(dian)池(chi)的(de)使用壽命，并(bing)避免(mian)簡易充(chong)電(dian)器在(zai)充(chong)電(dian)時可(ke)能(neng)(neng)對(dui)電(dian)池(chi)造成損害的(de)情況(kuang)發(fa)生，具(ju)有一(yi)定(ding)的(de)智能(neng)(neng)功(gong)能(neng)(neng)，符合目前的(de)環境(jing)保護(hu)(hu)潮(chao)流。