1.蓄電池的特點

目前常用(yong)的(de)四種化學電(dian)(dian)池(chi)(chi)(chi)(chi)是鉛(qian)酸(suan)電(dian)(dian)池(chi)(chi)(chi)(chi)（PbSO4）、鋰離子電(dian)(dian)池(chi)(chi)(chi)(chi)（Li＋）、鎳鉻電(dian)(dian)池(chi)(chi)(chi)(chi)（NiCd）和鎳氫電(dian)(dian)池(chi)(chi)(chi)(chi)（NiMH）。由于環保(bao)問題和對電(dian)(dian)池(chi)(chi)(chi)(chi)的(de)要求越來越高等綜合因(yin)素，推動(dong)了新電(dian)(dian)池(chi)(chi)(chi)(chi)技術的(de)發展。

1．1 鎳鉻電池和(he)鎳氫電池

鎳(nie)(nie)鉻電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)容(rong)量比鎳(nie)(nie)氫(qing)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)或(huo)(huo)鋰離(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)低(di)，具(ju)有低(di)阻(zu)抗特性(xing)，對于(yu)需(xu)(xu)要短時(shi)間大電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)(de)應用場合很具(ju)吸引(yin)力。但(dan)鎳(nie)(nie)鉻電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)如果未(wei)經充(chong)(chong)(chong)(chong)分放電(dian)(dian)(dian)(dian)(dian)(dian)又進行(xing)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，或(huo)(huo)者(zhe)長時(shi)間處于(yu)小(xiao)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)放電(dian)(dian)(dian)(dian)(dian)(dian)狀態，就會(hui)產生枝狀晶(jing)體(ti)(ti)，引(yin)起“記憶效應”，從而(er)導致(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)內阻(zu)變(bian)大，容(rong)量變(bian)小(xiao)，縮短了電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)壽命(ming)。如果在(zai)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)前進行(xing)完全放電(dian)(dian)(dian)(dian)(dian)(dian)，使每節電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓降到1．0V左右，就能(neng)(neng)消除引(yin)起“記憶效應”的(de)(de)(de)(de)枝狀晶(jing)體(ti)(ti)，恢復(fu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)性(xing)能(neng)(neng)。鎳(nie)(nie)氫(qing)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)具(ju)有較(jiao)高(gao)的(de)(de)(de)(de)容(rong)量，但(dan)其(qi)自放電(dian)(dian)(dian)(dian)(dian)(dian)率(lv)也較(jiao)高(gao)，約(yue)為(wei)鎳(nie)(nie)鉻電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)二(er)倍。在(zai)初始階段其(qi)放電(dian)(dian)(dian)(dian)(dian)(dian)率(lv)尤(you)高(gao)（每天放掉1％）。所(suo)以(yi)(yi)鎳(nie)(nie)氫(qing)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)不宜用于(yu)需(xu)(xu)要長時(shi)間保持(chi)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)容(rong)量的(de)(de)(de)(de)場合。就充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)而(er)言，兩(liang)種電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)非(fei)常相似，都是以(yi)(yi)恒流(liu)的(de)(de)(de)(de)方式(shi)進行(xing)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，可(ke)采(cai)用快速(su)(su)、標準或(huo)(huo)者(zhe)涓流(liu)的(de)(de)(de)(de)方式(shi)進行(xing)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。它們都能(neng)(neng)以(yi)(yi)超過(guo)2C（C為(wei)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)容(rong)量，單位為(wei)安(an)培）的(de)(de)(de)(de)速(su)(su)率(lv)進行(xing)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)（但(dan)一般(ban)采(cai)用C／2速(su)(su)率(lv)）。由于(yu)存在(zai)內部(bu)損(sun)(sun)(sun)耗，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)效率(lv)一般(ban)小(xiao)于(yu)100％，所(suo)以(yi)(yi)，在(zai)采(cai)用C／2的(de)(de)(de)(de)速(su)(su)率(lv)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，通(tong)常需(xu)(xu)要兩(liang)個多小(xiao)時(shi)才能(neng)(neng)把(ba)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)充(chong)(chong)(chong)(chong)滿。充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過(guo)程中的(de)(de)(de)(de)損(sun)(sun)(sun)耗隨(sui)著充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)速(su)(su)率(lv)和(he)(he)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)不同(tong)而(er)不同(tong)。在(zai)恒流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓會(hui)緩慢達到峰(feng)值(zhi)(zhi)（ΔV／Δt變(bian)為(wei)0），鎳(nie)(nie)氫(qing)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)需(xu)(xu)在(zai)這個峰(feng)值(zhi)(zhi)點終(zhong)止(zhi)快速(su)(su)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，鎳(nie)(nie)鉻電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)須在(zai)峰(feng)值(zhi)(zhi)點后(hou)當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓開(kai)始下(xia)降時(shi)（ΔV／Δt變(bian)為(wei)負）即終(zhong)止(zhi)快速(su)(su)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，否則會(hui)導致(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)內壓力和(he)(he)溫(wen)度上升而(er)損(sun)(sun)(sun)壞電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)。當(dang)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)速(su)(su)率(lv)大于(yu)C／2時(shi)，則要監測電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓和(he)(he)溫(wen)度，因為(wei)當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)快充(chong)(chong)(chong)(chong)滿時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)溫(wen)度會(hui)急劇(ju)上升。對于(yu)鎳(nie)(nie)鉻電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)和(he)(he)鎳(nie)(nie)氫(qing)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)，還可(ke)以(yi)(yi)采(cai)用比較(jiao)簡(jian)便的(de)(de)(de)(de)涓流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，這時(shi)只會(hui)造成極小(xiao)的(de)(de)(de)(de)溫(wen)升，不會(hui)損(sun)(sun)(sun)壞電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)，也就無需(xu)(xu)終(zhong)止(zhi)涓流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)或(huo)(huo)者(zhe)監測電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓。允許的(de)(de)(de)(de)最大涓流(liu)隨(sui)著電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)類型和(he)(he)環境溫(wen)度的(de)(de)(de)(de)不同(tong)而(er)不同(tong)，典型條(tiao)件下(xia)C／15較(jiao)為(wei)安(an)全。

1．2 鋰離子電池

過去(qu)幾年中，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)技(ji)術領域最(zui)(zui)突出(chu)的(de)(de)創(chuang)新就是(shi)鋰(li)離(li)(li)(li)子(zi)(zi)(zi)(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)。相對(dui)于鎳基(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)而言，鋰(li)離(li)(li)(li)子(zi)(zi)(zi)(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)具(ju)有更高(gao)的(de)(de)容(rong)(rong)量(liang)(liang)。從容(rong)(rong)量(liang)(liang)／體積比來(lai)(lai)衡量(liang)(liang)，鋰(li)離(li)(li)(li)子(zi)(zi)(zi)(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)比鎳氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)高(gao)出(chu)10％～30％，從容(rong)(rong)量(liang)(liang)／質(zhi)量(liang)(liang)比來(lai)(lai)看，鋰(li)離(li)(li)(li)子(zi)(zi)(zi)(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)比鎳氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)高(gao)出(chu)近兩(liang)倍。但鋰(li)離(li)(li)(li)子(zi)(zi)(zi)(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)對(dui)于過充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)和欠充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)很敏感。要達到最(zui)(zui)大(da)容(rong)(rong)量(liang)(liang)就必須充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)到最(zui)(zui)高(gao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，而過高(gao)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和過大(da)的(de)(de)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)或放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流又會造成(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)永久性損壞(huai)。如果多次放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)至過低的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)則會造成(cheng)容(rong)(rong)量(liang)(liang)損失，所以，充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)和放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)都(dou)須限制(zhi)其電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流，以保(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)不(bu)受損壞(huai)。鋰(li)離(li)(li)(li)子(zi)(zi)(zi)(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)方式不(bu)同(tong)于鎳基(ji)材料的(de)(de)化學電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)，充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)需(xu)用一個電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)―電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流源來(lai)(lai)進(jin)行(xing)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。為了獲得最(zui)(zui)大(da)的(de)(de)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)而又不(bu)損壞(huai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)，須使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)持在1％的(de)(de)精(jing)度內。快速充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)開(kai)始時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)比較(jiao)低，充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流即為電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流極限。隨著充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)進(jin)行(xing)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)緩慢(man)上升(sheng)，最(zui)(zui)終(zhong)當(dang)每節電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)達到浮(fu)空電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya) 4．2V時(shi)，此時(shi)即可終(zhong)止充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。

2　總體設計

2．1 充(chong)電器芯(xin)片(pian)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(jin)行(xing)充(chong)電(dian)(dian)(dian)(dian)。圖1為其QSOP封(feng)裝的管腳(jiao)(jiao)(jiao)(jiao)圖。圖中，1腳(jiao)(jiao)(jiao)(jiao)DCIN和(he)(he)(he)4腳(jiao)(jiao)(jiao)(jiao)GND及15腳(jiao)(jiao)(jiao)(jiao)PGND分別(bie)為電(dian)(dian)(dian)(dian)源和(he)(he)(he)地端(duan)(duan)(duan)。2腳(jiao)(jiao)(jiao)(jiao)VL端(duan)(duan)(duan)可提供3．3V，1％的電(dian)(dian)(dian)(dian)壓(ya)(ya)基(ji)準。3腳(jiao)(jiao)(jiao)(jiao)CCI和(he)(he)(he)5腳(jiao)(jiao)(jiao)(jiao)CCV分別(bie)為電(dian)(dian)(dian)(dian)流和(he)(he)(he)電(dian)(dian)(dian)(dian)壓(ya)(ya)調(diao)節(jie)(jie)(jie)回(hui)路(lu)補償端(duan)(duan)(duan)。7腳(jiao)(jiao)(jiao)(jiao)ISET和(he)(he)(he)6腳(jiao)(jiao)(jiao)(jiao)VSET分別(bie)為充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流和(he)(he)(he)電(dian)(dian)(dian)(dian)壓(ya)(ya)回(hui)路(lu)設定(ding)端(duan)(duan)(duan)。8腳(jiao)(jiao)(jiao)(jiao)OFFV為電(dian)(dian)(dian)(dian)壓(ya)(ya)調(diao)節(jie)(jie)(jie)回(hui)路(lu)控(kong)制(zhi)端(duan)(duan)(duan)，對于(yu)鎳基(ji)電(dian)(dian)(dian)(dian)池置為高電(dian)(dian)(dian)(dian)平(ping)。當(dang)VL端(duan)(duan)(duan)電(dian)(dian)(dian)(dian)壓(ya)(ya)低于(yu)3V時(shi)，9腳(jiao)(jiao)(jiao)(jiao)PWROK輸(shu)出低電(dian)(dian)(dian)(dian)平(ping)，可給MCU提供復位信號。10腳(jiao)(jiao)(jiao)(jiao)CELL2為鋰離子(zi)電(dian)(dian)(dian)(dian)池選擇端(duan)(duan)(duan)，低電(dian)(dian)(dian)(dian)平(ping)時(shi)為一節(jie)(jie)(jie)，高電(dian)(dian)(dian)(dian)平(ping)時(shi)為兩節(jie)(jie)(jie)。11腳(jiao)(jiao)(jiao)(jiao)ON為充(chong)電(dian)(dian)(dian)(dian)控(kong)制(zhi)端(duan)(duan)(duan)，低電(dian)(dian)(dian)(dian)平(ping)時(shi)停(ting)止(zhi)充(chong)電(dian)(dian)(dian)(dian)。12腳(jiao)(jiao)(jiao)(jiao)BATT端(duan)(duan)(duan)接電(dian)(dian)(dian)(dian)池正極(ji)。13腳(jiao)(jiao)(jiao)(jiao)CS＋和(he)(he)(he)14腳(jiao)(jiao)(jiao)(jiao)CS－為內(nei)部(bu)電(dian)(dian)(dian)(dian)流檢測放大器(qi)輸(shu)入端(duan)(duan)(duan)。16腳(jiao)(jiao)(jiao)(jiao)DRV為外部(bu)調(diao)節(jie)(jie)(jie)晶體管驅動(dong)端(duan)(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選用(yong)AT89C51，片內帶4K的(de)EEPROM，這(zhe)樣就無需擴(kuo)展程序存儲器(qi)，簡化了電(dian)(dian)(dian)(dian)路(lu)(lu)設(she)(she)計。電(dian)(dian)(dian)(dian)源回路(lu)(lu)中，220V的(de)交流(liu)(liu)電(dian)(dian)(dian)(dian)經(jing)(jing)變壓器(qi)降為(wei) 12V，經(jing)(jing)過整流(liu)(liu)濾波變為(wei)14V左右，作為(wei)MAX846A的(de)充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)源，另外(wai)經(jing)(jing)7805穩(wen)壓后作為(wei)其他電(dian)(dian)(dian)(dian)路(lu)(lu)單元的(de)工作電(dian)(dian)(dian)(dian)源。調節電(dian)(dian)(dian)(dian)路(lu)(lu)主要(yao)由(you)A／D和(he)D／A構成(cheng)，用(yong)于檢測電(dian)(dian)(dian)(dian)池(chi)的(de)電(dian)(dian)(dian)(dian)壓和(he)溫(wen)度及設(she)(she)置電(dian)(dian)(dian)(dian)池(chi)的(de)浮空電(dian)(dian)(dian)(dian)壓和(he)充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)。充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)路(lu)(lu)以MAX846A為(wei)中心，完成(cheng)充(chong)(chong)電(dian)(dian)(dian)(dian)過程。充(chong)(chong)電(dian)(dian)(dian)(dian)過程的(de)啟停及充(chong)(chong)電(dian)(dian)(dian)(dian)方式的(de)選擇由(you)單片機(ji)對MAX846A進行控制來實(shi)現。放電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)路(lu)(lu)用(yong)以消(xiao)除鎳(nie)鉻(ge)電(dian)(dian)(dian)(dian)池(chi)的(de)“記憶效應(ying)”。報警電(dian)(dian)(dian)(dian)路(lu)(lu)在系(xi)統(tong)工作時給出必(bi)要(yao)的(de)聲音提(ti)示(shi)(shi)(shi)。鍵(jian)盤(pan)和(he)顯(xian)示(shi)(shi)(shi)電(dian)(dian)(dian)(dian)路(lu)(lu)用(yong)于設(she)(she)置和(he)顯(xian)示(shi)(shi)(shi)相關的(de)參數(shu)。

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）鋰離子電池標準(zhun)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(cai)用(yong)零斜(xie)率(lv)終(zhong)止(zhi)充(chong)(chong)電(dian)(dian)（ΔV／Δt等于0），鋰離子電(dian)(dian)池(chi)采(cai)用(yong)頂端截止(zhi)。另外，在(zai)快速充(chong)(chong)電(dian)(dian)時(shi)，如電(dian)(dian)池(chi)電(dian)(dian)壓或(huo)者(zhe)溫度(du)超(chao)限以及充(chong)(chong)電(dian)(dian)時(shi)間超(chao)過三小時(shi)，系統都將停止(zhi)充(chong)(chong)電(dian)(dian)并蜂鳴(ming)提(ti)示(shi)。充(chong)(chong)電(dian)(dian)結束時(shi)數(shu)碼管顯示(shi)P并蜂鳴(ming)提(ti)示(shi)。出于對電(dian)(dian)池(chi)壽(shou)命(ming)的考慮，在(zai)多次快充(chong)(chong)后(hou)，建議采(cai)用(yong)標準(zhun)方式(shi)充(chong)(chong)電(dian)(dian)一次。

2．4 軟件設計

系統(tong)的(de)(de)軟件設計采用模(mo)(mo)塊式結構(gou)，主要由初(chu)始(shi)化程(cheng)序、充(chong)(chong)(chong)電(dian)(dian)(dian)方(fang)式設置(zhi)模(mo)(mo)塊、預(yu)處理(li)模(mo)(mo)塊、A／D轉(zhuan)(zhuan)換(huan)模(mo)(mo)塊、D／A轉(zhuan)(zhuan)換(huan)模(mo)(mo)塊、定時(shi)模(mo)(mo)塊和顯(xian)示(shi)模(mo)(mo)塊等部(bu)分(fen)組成。其(qi)中(zhong)，充(chong)(chong)(chong)電(dian)(dian)(dian)方(fang)式設置(zhi)模(mo)(mo)塊用于(yu)設置(zhi)電(dian)(dian)(dian)池(chi)類(lei)型和充(chong)(chong)(chong)電(dian)(dian)(dian)方(fang)式；A／D轉(zhuan)(zhuan)換(huan)模(mo)(mo)塊用于(yu)檢測(ce)電(dian)(dian)(dian)池(chi)的(de)(de)電(dian)(dian)(dian)壓和溫度，以(yi)確(que)定是否(fou)終(zhong)止(zhi)充(chong)(chong)(chong)電(dian)(dian)(dian)過程(cheng)；D／A轉(zhuan)(zhuan)換(huan)模(mo)(mo)塊用于(yu)設置(zhi)充(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流和電(dian)(dian)(dian)壓；定時(shi)模(mo)(mo)塊用于(yu)確(que)定零斜(xie)(xie)(xie)率(lv)或負斜(xie)(xie)(xie)率(lv)檢測(ce)的(de)(de)頻度以(yi)及(ji)快(kuai)充(chong)(chong)(chong)的(de)(de)時(shi)間監測(ce)，斜(xie)(xie)(xie)率(lv)檢測(ce)為每分(fen)鐘(zhong)一次(ci)，快(kuai)充(chong)(chong)(chong)的(de)(de)時(shi)間限為三(san)小時(shi)。系統(tong)程(cheng)序的(de)(de)流程(cheng)圖如(ru)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(neng)夠(gou)實現(xian)對(dui)一般的(de)蓄電(dian)池進行(xing)充電(dian)，而且還能(neng)夠(gou)實現(xian)相應的(de)過壓和溫(wen)度保(bao)護，從而可(ke)以(yi)充分(fen)發(fa)揮蓄電(dian)池的(de)性(xing)能(neng)，延長電(dian)池的(de)使(shi)用壽命，并避免簡(jian)易充電(dian)器(qi)在充電(dian)時可(ke)能(neng)對(dui)電(dian)池造(zao)成損害的(de)情(qing)況發(fa)生，具有一定的(de)智能(neng)功能(neng)，符合(he)目(mu)前的(de)環境保(bao)護潮流(liu)。