看(kan)到消息說手機用(yong)USB充電(dian)，充不(bu)滿，而且電(dian)量掉得(de)(de)快，搞得(de)(de)不(bu)好會(hui)漏電(dian)。用(yong)直充就沒有這個(ge)問(wen)題，真(zhen)的是這樣嗎(ma)？ 聽聽果殼網科學控的分析吧。“科學白(bai)癡”們可以直接跳到最后一段，看(kan)結(jie)論(lun)。

鋰電池的充電方式

   鋰電池的(de)(de)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)方式是(shi)(shi)(shi)限壓(ya)(ya)(ya)(ya)恒流(liu)(liu)，都(dou)是(shi)(shi)(shi)由(you)IC芯片控制(zhi)的(de)(de)，典型的(de)(de)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)方式是(shi)(shi)(shi)：先(xian)檢測待充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)池的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)，如果電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)低(di)于3V，要先(xian)進(jin)行(xing)預充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)，充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)為(wei)設(she)(she)定(ding)(ding)電(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)1/10，電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)升到3V后，進(jin)入標準充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)過(guo)程(cheng)。標準充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)過(guo)程(cheng)為(wei)：以設(she)(she)定(ding)(ding)電(dian)(dian)(dian)(dian)流(liu)(liu)進(jin)行(xing)恒流(liu)(liu)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)，電(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)升到4.20V時(shi)，改(gai)為(wei)恒壓(ya)(ya)(ya)(ya)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)，保(bao)持充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)為(wei)4.20V。此時(shi)，充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)逐(zhu)漸下降，當電(dian)(dian)(dian)(dian)流(liu)(liu)下降至設(she)(she)定(ding)(ding)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)1/10時(shi)，充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)結束。

USB充(chong)電可能沒充(chong)滿

    電(dian)(dian)(dian)(dian)(dian)腦(nao)的(de)USB輸出電(dian)(dian)(dian)(dian)(dian)壓為5V，一般(ban)都很(hen)精準(zhun)，之所(suo)以(yi)大家覺得USB充(chong)(chong)(chong)不(bu)滿，是(shi)因為USB輸出電(dian)(dian)(dian)(dian)(dian)流(liu)小，而充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)的(de)最(zui)后(hou)階段，需(xu)要有(you)涓(juan)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。涓(juan)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)是(shi)用來彌補電(dian)(dian)(dian)(dian)(dian)池(chi)在充(chong)(chong)(chong)滿電(dian)(dian)(dian)(dian)(dian)后(hou)由于自放電(dian)(dian)(dian)(dian)(dian)而造成的(de)容(rong)量(liang)損失(shi)。電(dian)(dian)(dian)(dian)(dian)池(chi)在充(chong)(chong)(chong)滿電(dian)(dian)(dian)(dian)(dian)后(hou)，由于自放電(dian)(dian)(dian)(dian)(dian)損失(shi)的(de)容(rong)量(liang)大約是(shi)標稱(cheng)容(rong)量(liang)的(de)5%。理(li)論上說涓(juan)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)要在充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)的(de)1/500級別(bie)，USB電(dian)(dian)(dian)(dian)(dian)流(liu)只有(you)500mA，涓(juan)流(liu)很(hen)小了，所(suo)以(yi)這個過程(cheng)很(hen)慢(man)很(hen)慢(man)，你等不(bu)及(ji)拔下來，5%就沒了。

   用什么充，只有電(dian)流的(de)區(qu)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(shi)(shi)用電(dian)(dian)腦USB，不(bu)都是(shi)(shi)那根(gen)線(xian)嘛，用什么(me)充(chong)(chong)，只有充(chong)(chong)電(dian)(dian)電(dian)(dian)流的區別，都得(de)捅手機(ji)的“屁股”，只要你用USB線(xian)充(chong)(chong)電(dian)(dian)，另一(yi)端是(shi)(shi)神馬，原理上都是(shi)(shi)一(yi)樣的，只是(shi)(shi)充(chong)(chong)得(de)快(kuai)慢問(wen)題(ti)。

   經測試，筆(bi)記本電(dian)(dian)(dian)腦USB口對手機(ji)充(chong)電(dian)(dian)(dian)，與座(zuo)充(chong)對裸手機(ji)電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)相(xiang)比，充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)壓(ya)略高(gao)（5V:4.2V），充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流略低（190mA:220mA），但換臺式機(ji)的USB口，充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)壓(ya)仍為5V，充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流漲(zhang)為230mA。

   兩種充(chong)(chong)電方式(shi)并無明顯不(bu)同，USB充(chong)(chong)電會漏電的(de)說(shuo)法不(bu)正確。