看到(dao)消息說手(shou)機(ji)用(yong)(yong)USB充電，充不(bu)滿，而且電量掉得快，搞(gao)得不(bu)好會漏電。用(yong)(yong)直充就沒有這個問題，真的是這樣嗎？ 聽聽果殼網(wang)科(ke)(ke)學控的分析吧。“科(ke)(ke)學白癡”們可以(yi)直接跳到(dao)最后一(yi)段，看結(jie)論(lun)。

鋰電池的充電方式

   鋰電池的(de)(de)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)(shi)是(shi)(shi)限壓恒(heng)流，都是(shi)(shi)由(you)IC芯片控制的(de)(de)，典型的(de)(de)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)(shi)是(shi)(shi)：先檢測(ce)待(dai)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)池的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓，如果電(dian)(dian)(dian)(dian)(dian)(dian)壓低(di)于3V，要(yao)先進行預充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流為設定電(dian)(dian)(dian)(dian)(dian)(dian)流的(de)(de)1/10，電(dian)(dian)(dian)(dian)(dian)(dian)壓升到(dao)(dao)3V后，進入標(biao)準充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過程(cheng)。標(biao)準充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過程(cheng)為：以(yi)設定電(dian)(dian)(dian)(dian)(dian)(dian)流進行恒(heng)流充(chong)(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)壓升到(dao)(dao)4.20V時，改為恒(heng)壓充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，保持充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓為4.20V。此時，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流逐漸下降，當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)流下降至設定充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流的(de)(de)1/10時，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)結束。

USB充電可能沒充滿

    電(dian)(dian)(dian)腦的(de)USB輸(shu)出(chu)電(dian)(dian)(dian)壓(ya)為5V，一(yi)般都很精準，之所以(yi)大(da)家覺得USB充(chong)(chong)不滿(man)(man)，是因為USB輸(shu)出(chu)電(dian)(dian)(dian)流小(xiao)(xiao)，而(er)充(chong)(chong)電(dian)(dian)(dian)的(de)最后階段，需要有涓(juan)流充(chong)(chong)電(dian)(dian)(dian)。涓(juan)流充(chong)(chong)電(dian)(dian)(dian)是用來彌補(bu)電(dian)(dian)(dian)池在充(chong)(chong)滿(man)(man)電(dian)(dian)(dian)后由于(yu)自放電(dian)(dian)(dian)而(er)造(zao)成的(de)容量(liang)損(sun)失。電(dian)(dian)(dian)池在充(chong)(chong)滿(man)(man)電(dian)(dian)(dian)后，由于(yu)自放電(dian)(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(lun)上說涓(juan)流充(chong)(chong)電(dian)(dian)(dian)要在充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流的(de)1/500級別，USB電(dian)(dian)(dian)流只(zhi)有500mA，涓(juan)流很小(xiao)(xiao)了，所以(yi)這個過程(cheng)很慢(man)很慢(man)，你等不及拔下來，5%就沒了。

   用什么充，只有電(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(shi)(shi)用電(dian)腦USB，不都是(shi)(shi)那根線嘛，用什(shen)么充(chong)(chong)，只有充(chong)(chong)電(dian)電(dian)流的區別，都得捅(tong)手機的“屁(pi)股”，只要你用USB線充(chong)(chong)電(dian)，另一端是(shi)(shi)神馬，原理上都是(shi)(shi)一樣的，只是(shi)(shi)充(chong)(chong)得快慢(man)問題(ti)。

   經(jing)測試(shi)，筆記本(ben)電(dian)腦USB口對手機(ji)充(chong)(chong)電(dian)，與座(zuo)充(chong)(chong)對裸手機(ji)電(dian)池充(chong)(chong)電(dian)相比，充(chong)(chong)電(dian)電(dian)壓(ya)略(lve)高（5V:4.2V），充(chong)(chong)電(dian)電(dian)流略(lve)低（190mA:220mA），但換臺式機(ji)的USB口，充(chong)(chong)電(dian)電(dian)壓(ya)仍為5V，充(chong)(chong)電(dian)電(dian)流漲為230mA。

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