看到消(xiao)息說手機用USB充電(dian)，充不滿，而且電(dian)量掉得快(kuai)，搞得不好會(hui)漏(lou)電(dian)。用直充就沒有這個(ge)問題，真(zhen)的(de)是這樣嗎(ma)？ 聽聽果殼網科(ke)學控的(de)分析吧。“科(ke)學白癡”們(men)可以(yi)直接(jie)跳到最后一段，看結論。

鋰電池的充電方式

   鋰電池的充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)是(shi)限壓(ya)恒(heng)流(liu)，都(dou)是(shi)由IC芯片控(kong)制(zhi)的，典型的充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)是(shi)：先檢測待充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)池的電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，如果電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)低于3V，要先進行(xing)預充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)為(wei)(wei)設(she)(she)定(ding)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的1/10，電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)升到3V后，進入(ru)標(biao)準充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過程。標(biao)準充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過程為(wei)(wei)：以設(she)(she)定(ding)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)進行(xing)恒(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)升到4.20V時(shi)，改為(wei)(wei)恒(heng)壓(ya)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，保持充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)為(wei)(wei)4.20V。此時(shi)，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)逐漸(jian)下降，當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)下降至設(she)(she)定(ding)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的1/10時(shi)，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)結束。

USB充電可(ke)能沒充滿

    電(dian)(dian)(dian)(dian)(dian)腦的USB輸出(chu)電(dian)(dian)(dian)(dian)(dian)壓為(wei)5V，一般都很(hen)精準，之所以大(da)家(jia)覺(jue)得USB充(chong)不滿，是(shi)因(yin)為(wei)USB輸出(chu)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)小，而(er)充(chong)電(dian)(dian)(dian)(dian)(dian)的最后階段，需要(yao)有(you)(you)涓(juan)流(liu)(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)。涓(juan)流(liu)(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)是(shi)用來(lai)彌補電(dian)(dian)(dian)(dian)(dian)池在充(chong)滿電(dian)(dian)(dian)(dian)(dian)后由于(yu)自(zi)放電(dian)(dian)(dian)(dian)(dian)而(er)造成的容量(liang)損失。電(dian)(dian)(dian)(dian)(dian)池在充(chong)滿電(dian)(dian)(dian)(dian)(dian)后，由于(yu)自(zi)放電(dian)(dian)(dian)(dian)(dian)損失的容量(liang)大(da)約(yue)是(shi)標(biao)稱容量(liang)的5%。理論上(shang)說涓(juan)流(liu)(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)要(yao)在充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的1/500級別，USB電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)只有(you)(you)500mA，涓(juan)流(liu)(liu)很(hen)小了，所以這(zhe)個過程很(hen)慢(man)很(hen)慢(man)，你等不及拔下來(lai)，5%就沒了。

   用什么充，只有(you)電流的區別

   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(huan)是用電(dian)腦USB，不(bu)都(dou)是那根線嘛(ma)，用什(shen)么充(chong)(chong)，只有充(chong)(chong)電(dian)電(dian)流的(de)區(qu)別，都(dou)得捅手機的(de)“屁(pi)股”，只要你用USB線充(chong)(chong)電(dian)，另一端(duan)是神(shen)馬，原理上都(dou)是一樣(yang)的(de)，只是充(chong)(chong)得快慢問題(ti)。

   經(jing)測試，筆(bi)記本電(dian)(dian)腦USB口(kou)對(dui)手機(ji)充(chong)電(dian)(dian)，與座充(chong)對(dui)裸(luo)手機(ji)電(dian)(dian)池充(chong)電(dian)(dian)相(xiang)比，充(chong)電(dian)(dian)電(dian)(dian)壓略高（5V:4.2V），充(chong)電(dian)(dian)電(dian)(dian)流(liu)略低（190mA:220mA），但換(huan)臺式機(ji)的USB口(kou)，充(chong)電(dian)(dian)電(dian)(dian)壓仍為5V，充(chong)電(dian)(dian)電(dian)(dian)流(liu)漲為230mA。

   兩種充電(dian)方式(shi)并無明(ming)顯不(bu)(bu)同，USB充電(dian)會漏電(dian)的說法不(bu)(bu)正(zheng)確。