看(kan)到消息說手機用USB充電，充不(bu)滿，而且電量掉(diao)得(de)(de)快，搞得(de)(de)不(bu)好(hao)會漏(lou)電。用直(zhi)充就沒有這個(ge)問(wen)題，真(zhen)的是這樣嗎？ 聽聽果殼網科學控的分析吧。“科學白癡”們可以直(zhi)接跳到最后一(yi)段，看(kan)結論。

鋰電池的充電方式

   鋰電池的(de)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)方(fang)式是(shi)(shi)限壓(ya)恒流(liu)(liu)，都是(shi)(shi)由IC芯片控(kong)制(zhi)的(de)，典型的(de)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)方(fang)式是(shi)(shi)：先檢測待充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)電(dian)池(chi)的(de)電(dian)壓(ya)，如果電(dian)壓(ya)低于3V，要先進(jin)行(xing)預充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)電(dian)流(liu)(liu)為(wei)設定(ding)(ding)電(dian)流(liu)(liu)的(de)1/10，電(dian)壓(ya)升到3V后，進(jin)入標(biao)準(zhun)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)過(guo)程。標(biao)準(zhun)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)過(guo)程為(wei)：以設定(ding)(ding)電(dian)流(liu)(liu)進(jin)行(xing)恒流(liu)(liu)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)，電(dian)池(chi)電(dian)壓(ya)升到4.20V時(shi)，改為(wei)恒壓(ya)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)，保持充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)電(dian)壓(ya)為(wei)4.20V。此時(shi)，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)電(dian)流(liu)(liu)逐漸(jian)下降，當電(dian)流(liu)(liu)下降至(zhi)設定(ding)(ding)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)電(dian)流(liu)(liu)的(de)1/10時(shi)，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)結(jie)束(shu)。

USB充(chong)電(dian)可(ke)能(neng)沒充(chong)滿(man)

    電(dian)(dian)腦的(de)USB輸(shu)出電(dian)(dian)壓為5V，一般都很精準，之所以大(da)家覺得USB充不(bu)滿(man)，是因(yin)為USB輸(shu)出電(dian)(dian)流(liu)小，而充電(dian)(dian)的(de)最后階段，需要(yao)有(you)涓(juan)流(liu)充電(dian)(dian)。涓(juan)流(liu)充電(dian)(dian)是用來彌補(bu)電(dian)(dian)池(chi)在充滿(man)電(dian)(dian)后由于自放電(dian)(dian)而造(zao)成的(de)容量(liang)損(sun)失。電(dian)(dian)池(chi)在充滿(man)電(dian)(dian)后，由于自放電(dian)(dian)損(sun)失的(de)容量(liang)大(da)約是標(biao)稱容量(liang)的(de)5%。理論上說涓(juan)流(liu)充電(dian)(dian)要(yao)在充電(dian)(dian)電(dian)(dian)流(liu)的(de)1/500級(ji)別(bie)，USB電(dian)(dian)流(liu)只有(you)500mA，涓(juan)流(liu)很小了(le)，所以這個(ge)過(guo)程很慢(man)很慢(man)，你等不(bu)及拔下來，5%就沒(mei)了(le)。

   用什(shen)么充，只(zhi)有電流的區別(bie)

   另外手機數碼產品的鋰電池都有保護板，有限制最低電壓和限制充電電流的作用。而且現在的手機無論是用充電器還是(shi)用(yong)(yong)電(dian)(dian)腦USB，不都(dou)是(shi)那根(gen)線嘛，用(yong)(yong)什么充，只(zhi)有(you)充電(dian)(dian)電(dian)(dian)流的區(qu)別(bie)，都(dou)得捅(tong)手機的“屁股”，只(zhi)要你用(yong)(yong)USB線充電(dian)(dian)，另一端是(shi)神馬，原理上都(dou)是(shi)一樣的，只(zhi)是(shi)充得快慢問題。

   經測(ce)試，筆記本(ben)電(dian)(dian)(dian)(dian)腦USB口(kou)對(dui)手機充(chong)電(dian)(dian)(dian)(dian)，與座充(chong)對(dui)裸手機電(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)相比，充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓略高（5V:4.2V），充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)略低（190mA:220mA），但換臺式機的USB口(kou)，充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓仍為5V，充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)漲為230mA。

   兩(liang)種充電(dian)方式并無明顯不(bu)同，USB充電(dian)會漏電(dian)的說法不(bu)正確。