看(kan)到消息(xi)說(shuo)手機用USB充電(dian)(dian)，充不滿，而(er)且電(dian)(dian)量掉(diao)得(de)快，搞得(de)不好會漏電(dian)(dian)。用直充就沒有這(zhe)個問(wen)題(ti)，真的是這(zhe)樣嗎(ma)？ 聽(ting)聽(ting)果(guo)殼網科(ke)(ke)學(xue)控的分(fen)析吧。“科(ke)(ke)學(xue)白癡”們可以(yi)直接跳到最后一段，看(kan)結論。

鋰電池的充電方式

   鋰電池的(de)充(chong)(chong)電(dian)(dian)(dian)方式是限壓(ya)(ya)恒流(liu)，都是由(you)IC芯片控制的(de)，典型(xing)的(de)充(chong)(chong)電(dian)(dian)(dian)方式是：先檢測(ce)待充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)池的(de)電(dian)(dian)(dian)壓(ya)(ya)，如果電(dian)(dian)(dian)壓(ya)(ya)低(di)于3V，要先進(jin)行預充(chong)(chong)電(dian)(dian)(dian)，充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)為(wei)設(she)定(ding)(ding)電(dian)(dian)(dian)流(liu)的(de)1/10，電(dian)(dian)(dian)壓(ya)(ya)升(sheng)到(dao)3V后，進(jin)入標準(zhun)充(chong)(chong)電(dian)(dian)(dian)過(guo)程(cheng)。標準(zhun)充(chong)(chong)電(dian)(dian)(dian)過(guo)程(cheng)為(wei)：以設(she)定(ding)(ding)電(dian)(dian)(dian)流(liu)進(jin)行恒流(liu)充(chong)(chong)電(dian)(dian)(dian)，電(dian)(dian)(dian)池電(dian)(dian)(dian)壓(ya)(ya)升(sheng)到(dao)4.20V時(shi)(shi)，改為(wei)恒壓(ya)(ya)充(chong)(chong)電(dian)(dian)(dian)，保持充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)壓(ya)(ya)為(wei)4.20V。此時(shi)(shi)，充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)逐漸下降，當電(dian)(dian)(dian)流(liu)下降至設(she)定(ding)(ding)充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)的(de)1/10時(shi)(shi)，充(chong)(chong)電(dian)(dian)(dian)結(jie)束。

USB充電(dian)可能沒充滿(man)

    電(dian)(dian)(dian)(dian)腦的USB輸出電(dian)(dian)(dian)(dian)壓為5V，一般(ban)都很精準，之所以大(da)家覺得USB充不滿(man)，是(shi)(shi)因為USB輸出電(dian)(dian)(dian)(dian)流(liu)小，而充電(dian)(dian)(dian)(dian)的最后階段，需要(yao)有涓(juan)(juan)流(liu)充電(dian)(dian)(dian)(dian)。涓(juan)(juan)流(liu)充電(dian)(dian)(dian)(dian)是(shi)(shi)用來彌補(bu)電(dian)(dian)(dian)(dian)池在(zai)充滿(man)電(dian)(dian)(dian)(dian)后由(you)(you)于(yu)自放電(dian)(dian)(dian)(dian)而造成的容量損失。電(dian)(dian)(dian)(dian)池在(zai)充滿(man)電(dian)(dian)(dian)(dian)后，由(you)(you)于(yu)自放電(dian)(dian)(dian)(dian)損失的容量大(da)約(yue)是(shi)(shi)標(biao)稱容量的5%。理論上說涓(juan)(juan)流(liu)充電(dian)(dian)(dian)(dian)要(yao)在(zai)充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)的1/500級(ji)別，USB電(dian)(dian)(dian)(dian)流(liu)只(zhi)有500mA，涓(juan)(juan)流(liu)很小了，所以這個過程(cheng)很慢(man)很慢(man)，你等不及拔下來，5%就(jiu)沒了。

   用什(shen)么充，只有(you)電(dian)流的區別

   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用(yong)電(dian)腦(nao)USB，不都(dou)是那根線嘛，用(yong)什(shen)么充，只有(you)充電(dian)電(dian)流的(de)(de)區別，都(dou)得捅(tong)手機的(de)(de)“屁(pi)股”，只要你(ni)用(yong)USB線充電(dian)，另一端是神馬，原理上都(dou)是一樣的(de)(de)，只是充得快(kuai)慢問題。

   經(jing)測試，筆記本電(dian)(dian)(dian)腦USB口對(dui)手(shou)機(ji)充(chong)(chong)電(dian)(dian)(dian)，與座充(chong)(chong)對(dui)裸手(shou)機(ji)電(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)相比，充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)壓略(lve)高（5V:4.2V），充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)略(lve)低（190mA:220mA），但換(huan)臺式(shi)機(ji)的USB口，充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)壓仍為5V，充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)漲為230mA。

   兩種(zhong)充(chong)電方式并無明顯不同，USB充(chong)電會漏電的說法不正確。