一、锂(li)电池的原理

1、简述锂电(dian)池以及工(gong)作原理

锂离子(zi)(zi)电(dian)池自1990年问世以(yi)来，因其卓(zhuo)越的性能得到了(le)迅猛的发展，并(bing)广泛地(di)应用于社(she)会。锂离子(zi)(zi)电(dian)池以(yi)其它电(dian) 池所不(bu)可(ke)比拟的优势迅速占领(ling)了(le)许多领(ling)域，象大家熟知的移动(dong)电(dian)话、笔记本电(dian)脑(nao)、小型摄像机(ji)等等。

目前锂(li)(li)电(dian)(dian)(dian)(dian)池(chi)(chi)(chi)公认的(de)(de)基本原理是(shi)(shi)所谓的(de)(de)“摇(yao)椅理论”。锂(li)(li)电(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)冲(chong)放(fang)电(dian)(dian)(dian)(dian)不是(shi)(shi)通过(guo)传统的(de)(de)方(fang)式实(shi)现电(dian)(dian)(dian)(dian)子的(de)(de)转移，而(er)是(shi)(shi)通过(guo)锂(li)(li)离子在层(ceng)壮物质的(de)(de)晶(jing)体中的(de)(de)出入，发生(sheng)能量(liang)变(bian)化(hua)。在正(zheng)常冲(chong)放(fang)电(dian)(dian)(dian)(dian)情况(kuang)下(xia)，锂(li)(li)离子的(de)(de)出入一(yi)般只引起层(ceng)间距的(de)(de)变(bian)化(hua)，而(er)不会(hui)引起晶(jing)体结构的(de)(de)破(po)坏(huai)，因(yin)此从冲(chong)放(fang)电(dian)(dian)(dian)(dian)反映来讲，锂(li)(li)离子电(dian)(dian)(dian)(dian)池(chi)(chi)(chi)是(shi)(shi)一(yi)种理想的(de)(de)可逆(ni)电(dian)(dian)(dian)(dian)池(chi)(chi)(chi)。在冲(chong)放(fang)电(dian)(dian)(dian)(dian)时锂(li)(li)离子在电(dian)(dian)(dian)(dian)池(chi)(chi)(chi)正(zheng)负极往(wang)返出入，正(zheng)像(xiang)摇(yao)椅一(yi)样(yang)在正(zheng)负极间摇(yao)来摇(yao)去，故有人(ren)将锂(li)(li)离子电(dian)(dian)(dian)(dian)池(chi)(chi)(chi)形象(xiang)称为摇(yao)椅电(dian)(dian)(dian)(dian)池(chi)(chi)(chi)。

我们经常说的(de)(de)锂离子电池(chi)的(de)(de)优(you)越(yue)性(xing)是(shi)针对于传(chuan)统的(de)(de)镍镉电池(chi)（Ni/Cd）和镍氢电池(chi)（Ni/MH）来讲的(de)(de)。 具有工作电压高比能(neng)量大循(xun)环(huan)寿命(ming)长(zhang)自放电率低无记忆效应等(deng)优(you)点。

1.锂离子电池

锂离子(zi)电(dian)(dian)(dian)(dian)池(chi)(chi)包含两个被电(dian)(dian)(dian)(dian)解质阻隔的电(dian)(dian)(dian)(dian)极。电(dian)(dian)(dian)(dian)解质是(shi)一种离子(zi)导体和电(dian)(dian)(dian)(dian)子(zi)绝缘体。在放电(dian)(dian)(dian)(dian)过程中，电(dian)(dian)(dian)(dian)池(chi)(chi)将化学能(neng)转(zhuan)化为电(dian)(dian)(dian)(dian)能(neng)。电(dian)(dian)(dian)(dian)池(chi)(chi)包中可(ke)以包含几(ji)个或者平(ping)行串联的单个电(dian)(dian)(dian)(dian)池(chi)(chi)。

锂离子电池(chi)是一种被人们(men)熟知的rocking chair或(huo)者(zhe)swing电池(chi)，因为其在(zai)充放电过程(cheng)中电荷(he)媒介会在(zai)电解质中穿梭在(zai)电极材料中嵌入或(huo)者(zhe)迁(qian)出。

2.电池电压(ya)

在某(mou)种意义(yi)上，电(dian)(dian)池可以看作(zuo)“电(dian)(dian)荷”泵。正负极(ji)端的(de)(de)(de)压(ya)(ya)力差被(bei)称(cheng)作(zuo)为(wei)电(dian)(dian)压(ya)(ya)或(huo)者(zhe)电(dian)(dian)动(dong)势。通过外电(dian)(dian)路进行电(dian)(dian)子转(zhuan)移的(de)(de)(de)自由能以及在两(liang)个(ge)插层电(dian)(dian)极(ji)之间(jian)的(de)(de)(de)锂离子在两(liang)端之间(jian)的(de)(de)(de)化学电(dian)(dian)压(ya)(ya)是相(xiang)关(guan)的(de)(de)(de)。电(dian)(dian)极(ji)的(de)(de)(de)电(dian)(dian)势越高，材料(liao)中(zhong)的(de)(de)(de)Li就越难(nan)迁(qian)出。在放电(dian)(dian)过程中(zhong)，Li能够从阳极(ji)中(zhong)能量较高的(de)(de)(de)状态(tai)转(zhuan)移到阴极(ji)能量较低的(de)(de)(de)状态(tai)。

电池依靠(kao)其电化(hua)学(xue)活(huo)性物质来(lai)储存化(hua)学(xue)能(neng)(neng)。这些能(neng)(neng)量(liang)可以按(an)照需求通过氧化(hua)还(hai)原(yuan)反应来(lai)转化(hua)为电能(neng)(neng)。

3.电池的组成

锂离(li)子(zi)电池一(yi)般包含三个主要成(cheng)分(fen)：阳极(ji)，阴极(ji)，电解质。

阳极(ji)(ji)：在(zai)放电(dian)(dian)(dian)过(guo)程中电(dian)(dian)(dian)子(zi)通过(guo)外电(dian)(dian)(dian)路转移走，电(dian)(dian)(dian)极(ji)(ji)材料(liao)被氧化。大部分商用的电(dian)(dian)(dian)池使(shi)用基于炭/石墨的电(dian)(dian)(dian)极(ji)(ji)材料(liao)；不过(guo)金属(shu)或者合金也可以作为阳极(ji)(ji)材料(liao)。

阴极：在放电过(guo)程中，通(tong)过(guo)外电路接收电子；通(tong)常使(shi)用(yong)过(guo)渡(du)金(jin)属氧化(hua)物或(huo)者磷(lin)化(hua)物来(lai)作为阴极材料。

电(dian)(dian)(dian)解(jie)质：电(dian)(dian)(dian)解(jie)质是(shi)一个离(li)子(zi)导体，电(dian)(dian)(dian)子(zi)的不良导体。电(dian)(dian)(dian)解(jie)质阻隔电(dian)(dian)(dian)池的阴(yin)阳极(ji)，同时能提供电(dian)(dian)(dian)子(zi)转移(yi)的媒介。电(dian)(dian)(dian)解(jie)质一般使用一些(xie)(xie)非水的有(you)机溶(rong)剂(ji)，里面溶(rong)解(jie)一些(xie)(xie)含Li+的盐。比如LiPF6溶(rong)解(jie)在(zai)碳酸丙烯酯中。

备注：这里省略对(dui)隔膜和(he)外壳的介绍。

4.锂离子电池的充放电过程

A. 充电过程

电(dian)子一般在(zai)放电(dian)状态进行组(zu)装。在(zai)充(chong)电(dian)过(guo)程中(zhong)，阴极材料(liao)（如：LiCoO2）被氧(yang)化，锂离(li)子从层状的(de)插层材料(liao)中(zhong)脱出，穿过(guo)电(dian)解(jie)质(zhi)然后插层到(dao)石墨层之(zhi)中(zhong)。

B. 放(fang)电(dian)过程(cheng)

在放电过(guo)程(cheng)中，负极(ji)发(fa)生氧(yang)化反(fan)应(ying)(ying)，锂离子(zi)(zi)从阳极(ji)脱出然后穿过(guo)电解(jie)质(zhi)重新插(cha)层到阴极(ji)之(zhi)中。对应(ying)(ying)的(de)(de)，相应(ying)(ying)数量(liang)的(de)(de)电子(zi)(zi)会(hui)穿过(guo)外电路(lu)从而平(ping)衡电荷(he)。与(yu)此同时，正极(ji)材料(liao)从外电路(lu)接收(shou)电子(zi)(zi)和来(lai)自溶(rong)液中的(de)(de)Li+离子(zi)(zi)从而发(fa)生还原反(fan)应(ying)(ying)。电极(ji)和电解(jie)质(zhi)界(jie)面发(fa)生电子(zi)(zi)电流(liu)和离子(zi)(zi)电流(liu)的(de)(de)交换。

基于插(cha)(cha)层机理的电池(chi)——可(ke)逆的插(cha)(cha)入(ru)一个(ge)外来(lai)离子到固体(ti)结(jie)构中(zhong)，而不会破坏宿主材(cai)料的结(jie)构

2、锂电池(chi)日常使用(yong)过程中的常识

（1）、误区：“电池(chi)激活(huo)，前三次充电12小时(shi)以上(shang)”

对于锂电(dian)(dian)池(chi)(chi)(chi)的(de)(de)“激活”问题，众多的(de)(de)说(shuo)法(fa)是：充(chong)电(dian)(dian)时间一(yi)定要(yao)超(chao)过12小(xiao)时，反复做三次，以(yi)(yi)便激活电(dian)(dian)池(chi)(chi)(chi)。这种(zhong)“前(qian)三次充(chong)电(dian)(dian)要(yao)充(chong) 12小(xiao)时以(yi)(yi)上”的(de)(de)说(shuo)法(fa)，明显是从镍(nie)电(dian)(dian)池(chi)(chi)(chi)（如镍(nie)镉和(he)镍(nie)氢）延(yan)续下来的(de)(de)说(shuo)法(fa)。所以(yi)(yi)这种(zhong)说(shuo)法(fa)，可(ke)以(yi)(yi)说(shuo)一(yi)开始就是误传。经过抽样调查，可(ke)以(yi)(yi)看(kan)出有相当一(yi)部分(fen)人混淆(xiao)了两种(zhong)电(dian)(dian)池(chi)(chi)(chi)的(de)(de)充(chong)电(dian)(dian)方法(fa)。

锂电(dian)池和镍电(dian)池的(de)(de)充(chong)(chong)放电(dian)特(te)性有(you)非常(chang)大(da)(da)的(de)(de)区别(bie)，所查(cha)阅过(guo)的(de)(de)所有(you)严肃的(de)(de)正式技术资料都强调过(guo)充(chong)(chong)和过(guo)放电(dian)会对锂电(dian)池、特(te)别(bie)是液体(ti)锂离子电(dian)池造(zao)成(cheng)巨大(da)(da)的(de)(de)伤(shang)害。因而(er)充(chong)(chong)电(dian)最好按(an)照标准时(shi)间和标准方法充(chong)(chong)电(dian)，特(te)别(bie)是不要进行(xing)超过(guo)12个小时(shi)的(de)(de)超长(zhang)充(chong)(chong)电(dian)。通常(chang)，手机(ji)说明书上介绍(shao)的(de)(de)充(chong)(chong)电(dian)方法，就是适(shi)合该手机(ji)的(de)(de)标准充(chong)(chong)电(dian)方法。

（2）、 不益(yi)长时间(jian)充(chong)电(dian)、电(dian)池完全用(yong)完再(zai)充(chong)电(dian)

锂(li)电(dian)池的手机或充(chong)(chong)(chong)电(dian)器在(zai)电(dian)池充(chong)(chong)(chong)满(man)后都(dou)会自动停充(chong)(chong)(chong)，并不存(cun)在(zai)镍电(dian)充(chong)(chong)(chong)电(dian)器所谓的持(chi)续10几小时的“涓流(liu)”充(chong)(chong)(chong)电(dian)。如果锂(li)电(dian)池在(zai)充(chong)(chong)(chong)满(man)后，放在(zai)充(chong)(chong)(chong)电(dian)器上(shang)也是也不再(zai)充(chong)(chong)(chong)电(dian)。

超(chao)常时间充电和完全(quan)用空电量会造(zao)成过度(du)(du)充电和过度(du)(du)放电，将对锂离(li)(li)子电池(chi)的(de)正负极(ji)造(zao)成永久的(de)损坏，从(cong)分(fen)子层面看，过度(du)(du)放电将导(dao)致负极(ji)碳过度(du)(du)释出(chu)锂离(li)(li)子而使(shi)得(de)其(qi)片层结构出(chu)现塌(ta)陷，过度(du)(du)充电将把太(tai)多的(de)锂离(li)(li)子硬塞进负极(ji)碳结构里去，而使(shi)得(de)其(qi)中一些锂离(li)(li)子再也无法释放出(chu)来。

（3）、电池寿(shou)命

关于锂离子电池充(chong)放(fang)(fang)电循环(huan)的(de)(de)实验(yan)表，关于循环(huan)寿命的(de)(de)数据列出如下(xia)(DOD是放(fang)(fang)电深度的(de)(de)英文缩写(xie))：

循环寿命 (10％DOD)：> 1000次

循环寿(shou)命 (100％DOD)：> 200次

从上面(mian)数据可(ke)见，可(ke)充(chong)(chong)(chong)电(dian)(dian)(dian)(dian)次(ci)数和放(fang)电(dian)(dian)(dian)(dian)深度有(you)关，10％DOD时(shi)的(de)循(xun)环寿命(ming)要(yao)比100％DOD的(de)要(yao)长很多。当然 如果折(zhe)合到实(shi)际充(chong)(chong)(chong)电(dian)(dian)(dian)(dian)的(de)相对总容量10％*1000=100，100％*200=200，后(hou)者的(de)完全充(chong)(chong)(chong)放(fang)电(dian)(dian)(dian)(dian)还是要(yao)比较(jiao)好(hao)(hao)一(yi) 些。但是锂电(dian)(dian)(dian)(dian)池(chi)的(de)寿命(ming)主要(yao)体现在充(chong)(chong)(chong)放(fang)电(dian)(dian)(dian)(dian)周期(qi)上，这(zhei)个周期(qi)是一(yi)个绝对概念(nian)，上次(ci)使用了30％电(dian)(dian)(dian)(dian)力(li)，充(chong)(chong)(chong)满电(dian)(dian)(dian)(dian)，下次(ci)又使用了70％的(de)电(dian)(dian)(dian)(dian)力(li)，又充(chong)(chong)(chong)满电(dian)(dian)(dian)(dian)，这(zhei)个刚好(hao)(hao)是 一(yi)个充(chong)(chong)(chong)电(dian)(dian)(dian)(dian)周期(qi)。所以还是遵循(xun)锂电(dian)(dian)(dian)(dian)池(chi)发(fa)明者的(de)口号“即(ji)用即(ji)充(chong)(chong)(chong)，即(ji)充(chong)(chong)(chong)即(ji)用”的(de)方法使用锂电(dian)(dian)(dian)(dian)池(chi)。

（4）、定(ding)期(qi)深度充(chong)放电进行(xing)

锂离子(zi)电(dian)(dian)池一般(ban)都带(dai)有(you)(you)管(guan)理(li)(li)芯(xin)片(pian)和充电(dian)(dian)控(kong)制芯(xin)片(pian)。其中(zhong)管(guan)理(li)(li)芯(xin)片(pian)中(zhong)有(you)(you)一系(xi)列的寄(ji)(ji)存(cun)器，存(cun)有(you)(you)容量、 温度(du)、ID 、充电(dian)(dian)状态、放(fang)电(dian)(dian)次数等(deng)数值。这些(xie)数值在使(shi)用(yong)中(zhong)会逐(zhu)渐变(bian)化。使(shi)用(yong)说明中(zhong)的“使(shi)用(yong)一个月左右应该(gai)全充放(fang)一次”的做法主要的作用(yong)应该(gai)就(jiu)是修正(zheng)这些(xie)寄(ji)(ji)存(cun)器里不当 的值。

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