鼎汇3-创新平台,注册畅享文化之梦!锂电池-锂电池原理-特征-保护板原理-放电注意事项

锂(li)电(dian)池-锂(li)电(dian)池原理-特征-保护板原理-放(fang)电(dian)注意事项

信(xin)息来源：本(ben)站　日期：2017-12-06　

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锂电(dian)(dian)(dian)(dian)池(chi)是继镍(nie)镉(ge)、镍(nie)氢电(dian)(dian)(dian)(dian)池(chi)之后，可充(chong)电(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)池(chi)家族中的佼(jiao)佼(jiao)者．锂离子电(dian)(dian)(dian)(dian)池(chi)以其优秀的特性，被(bei)普遍(bian)应用于: 手机、摄录像机、笔记本电(dian)(dian)(dian)(dian)脑、无绳电(dian)(dian)(dian)(dian)话、电(dian)(dian)(dian)(dian)动工具、遥控(kong)或电(dian)(dian)(dian)(dian)动玩具、照相机等便携式电(dian)(dian)(dian)(dian)子设备中。

一、锂电池与镍镉、镍氢可充电池

锂(li)离(li)子电(dian)(dian)(dian)池的(de)负极(ji)(ji)为(wei)石墨晶体，正极(ji)(ji)通常为(wei)二氧化锂(li)。充电(dian)(dian)(dian)时锂(li)离(li)子由正极(ji)(ji)向负极(ji)(ji)运动(dong)而嵌入石墨层(ceng)中。放电(dian)(dian)(dian)时，锂(li)离(li)子从石墨晶体内负极(ji)(ji)表面脱(tuo)离(li)移向正极(ji)(ji)。所以(yi)，在该电(dian)(dian)(dian)池充放电(dian)(dian)(dian)过程(cheng)中锂(li)总是以(yi)锂(li)离(li)子形态呈现，而不是以(yi)金属锂(li)的(de)形态呈现。因(yin)而这种电(dian)(dian)(dian)池叫(jiao)做锂(li)离(li)子电(dian)(dian)(dian)池，简称锂(li)电(dian)(dian)(dian)池。

锂电(dian)(dian)(dian)池(chi)具有(you)(you)：体积小、容量(liang)大、重(zhong)量(liang)轻(qing)、无(wu)污染(ran)、单(dan)节电(dian)(dian)(dian)压高、自放电(dian)(dian)(dian)率低、电(dian)(dian)(dian)池(chi)循环次数多等优(you)点，但价钱(qian)较(jiao)贵(gui)。镍镉(ge)电(dian)(dian)(dian)池(chi)因容量(liang)低，自放电(dian)(dian)(dian)严(yan)重(zhong)，且对环境(jing)有(you)(you)污染(ran)，正逐步被淘(tao)汰。镍氢(qing)电(dian)(dian)(dian)池(chi)具有(you)(you)较(jiao)高的性能价钱(qian)比，且不污染(ran)环境(jing)，但单(dan)体电(dian)(dian)(dian)压只需1.2V，因而在运用范围上遭到限制。

二、锂电池的特性

1、具有更高的重量(liang)能量(liang)比(bi)、体积能量(liang)比(bi)；

2、电(dian)(dian)(dian)压(ya)(ya)高，单节锂电(dian)(dian)(dian)池(chi)电(dian)(dian)(dian)压(ya)(ya)为(wei)3.6V，等于3只镍(nie)镉或(huo)镍(nie)氢充电(dian)(dian)(dian)电(dian)(dian)(dian)池(chi)的(de)串联电(dian)(dian)(dian)压(ya)(ya)；

3、自放电(dian)小可长时间存放，这是该(gai)电(dian)池(chi)最突出的(de)优越(yue)性；

4、无(wu)(wu)记忆效应。锂电池不存(cun)在镍镉电池的所谓记忆效应，所以锂电池充电前无(wu)(wu)需(xu)放电；

5、寿(shou)命长(zhang)。正(zheng)常工作条(tiao)件下，锂(li)电(dian)池充/放(fang)电(dian)循环次数远大于500次；

6、可以快速充(chong)电(dian)。锂电(dian)池通常可以采(cai)用0.5～1倍容量的电(dian)流充(chong)电(dian)，使充(chong)电(dian)时间缩短至1～2小时；

7、可以(yi)随(sui)意(yi)并(bing)联运用；

8、由(you)于电池(chi)中不含镉、铅、汞等重(zhong)金属元(yuan)素，对环境(jing)无污(wu)染，是当代最先(xian)进的绿色电池(chi)；

9、本钱高。与其它可充电池(chi)相比，锂电池(chi)价钱较贵。

三、锂电池的内部结构

锂电池通常(chang)有(you)两种外型：圆柱(zhu)型和长方(fang)型。

电(dian)池(chi)内(nei)(nei)部采(cai)用(yong)螺旋绕制(zhi)结构，用(yong)一种非常(chang)精细而(er)渗透性很(hen)强的(de)聚乙烯薄膜(mo)隔离(li)材料在正、负极(ji)间(jian)间(jian)隔而(er)成(cheng)(cheng)。正极(ji)包括(kuo)由(you)锂和(he)二氧(yang)化钴组(zu)(zu)成(cheng)(cheng)的(de)锂离(li)子(zi)(zi)搜(sou)集极(ji)及(ji)由(you)铝薄膜(mo)组(zu)(zu)成(cheng)(cheng)的(de)电(dian)流搜(sou)集极(ji)。负极(ji)由(you)片状(zhuang)碳材料组(zu)(zu)成(cheng)(cheng)的(de)锂离(li)子(zi)(zi)搜(sou)集极(ji)和(he)铜薄膜(mo)组(zu)(zu)成(cheng)(cheng)的(de)电(dian)流搜(sou)集极(ji)组(zu)(zu)成(cheng)(cheng)。电(dian)池(chi)内(nei)(nei)充有有机电(dian)解质溶液。另外还装(zhuang)有安(an)全阀和(he)PTC元件(jian)，以便电(dian)池(chi)在不(bu)正常(chang)状(zhuang)态(tai)及(ji)输出短路(lu)时维护电(dian)池(chi)不(bu)受损坏。

单节锂电(dian)(dian)池(chi)的电(dian)(dian)压为3.6V，容量(liang)也(ye)不可能无限(xian)大，因此，常常将单节锂电(dian)(dian)池(chi)中止(zhi)串、并联处置，以(yi)满(man)足(zu)不同场所的恳(ken)求。

四、锂电池的充放电要求

1、锂(li)电(dian)(dian)池的充(chong)电(dian)(dian)：根据(ju)锂(li)电(dian)(dian)池的结构特性，最高充(chong)电(dian)(dian)终(zhong)止(zhi)电(dian)(dian)压(ya)应(ying)为4.2V，不能过充(chong)，否(fou)则会(hui)因正极(ji)的锂(li)离子拿走太(tai)多，而使电(dian)(dian)池报废。其充(chong)放(fang)电(dian)(dian)恳求较高，可采(cai)用专用的恒(heng)(heng)流、恒(heng)(heng)压(ya)充(chong)电(dian)(dian)器中止(zhi)充(chong)电(dian)(dian)。通常恒(heng)(heng)流充(chong)电(dian)(dian)至4.2V/节后转入(ru)恒(heng)(heng)压(ya)充(chong)电(dian)(dian)，当恒(heng)(heng)压(ya)充(chong)电(dian)(dian)电(dian)(dian)流降至100mA以内时，应(ying)中止(zhi)充(chong)电(dian)(dian)。

充(chong)电(dian)(dian)(dian)电(dian)(dian)(dian)流(liu)（mA）=0.1～1.5倍电(dian)(dian)(dian)池(chi)(chi)容量（如1350mAh的(de)电(dian)(dian)(dian)池(chi)(chi)，其充(chong)电(dian)(dian)(dian)电(dian)(dian)(dian)流(liu)可控制(zhi)在(zai)135～2025mA之(zhi)间(jian)）。常规充(chong)电(dian)(dian)(dian)电(dian)(dian)(dian)流(liu)可选择在(zai)0.5倍电(dian)(dian)(dian)池(chi)(chi)容量左右，充(chong)电(dian)(dian)(dian)时间(jian)约(yue)为2～3小时。

2、锂(li)电(dian)池(chi)的放(fang)(fang)(fang)电(dian)：因锂(li)电(dian)池(chi)的内部结构所致(zhi)，放(fang)(fang)(fang)电(dian)时(shi)锂(li)离(li)子(zi)(zi)不能全部移向正极，必需保管(guan)一部分锂(li)离(li)子(zi)(zi)在负极，以保证(zheng)在下(xia)次充电(dian)时(shi)锂(li)离(li)子(zi)(zi)能够畅通(tong)地嵌入通(tong)道(dao)。否(fou)则，电(dian)池(chi)寿命就(jiu)相应(ying)缩短。为了保证(zheng)石(shi)墨层中(zhong)放(fang)(fang)(fang)电(dian)后(hou)留有(you)部分锂(li)离(li)子(zi)(zi)，就(jiu)要(yao)严厉限制放(fang)(fang)(fang)电(dian)终止(zhi)最低(di)电(dian)压(ya)，也就(jiu)是说(shuo)锂(li)电(dian)池(chi)不能过放(fang)(fang)(fang)电(dian)。放(fang)(fang)(fang)电(dian)终止(zhi)电(dian)压(ya)通(tong)常为3.0V/节，最低(di)不能低(di)于2.5V/节。

电(dian)(dian)(dian)(dian)池(chi)放(fang)(fang)电(dian)(dian)(dian)(dian)时间长短与电(dian)(dian)(dian)(dian)池(chi)容量、放(fang)(fang)电(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)流(liu)大小有关。电(dian)(dian)(dian)(dian)池(chi)放(fang)(fang)电(dian)(dian)(dian)(dian)时间（小时）=电(dian)(dian)(dian)(dian)池(chi)容量/放(fang)(fang)电(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)流(liu)。锂电(dian)(dian)(dian)(dian)池(chi)放(fang)(fang)电(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)流(liu)(mA)不应(ying)超越电(dian)(dian)(dian)(dian)池(chi)容量的3倍。（如1000mAH电(dian)(dian)(dian)(dian)池(chi)，则放(fang)(fang)电(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)流(liu)应(ying)严厉(li)控制在3A以(yi)内）否(fou)则会使(shi)电(dian)(dian)(dian)(dian)池(chi)损坏。

目前(qian)市场上所(suo)售锂电(dian)(dian)池组内部均封(feng)有配套的(de)充(chong)放电(dian)(dian)维护(hu)板。只需(xu)控制(zhi)好外部的(de)充(chong)放电(dian)(dian)电(dian)(dian)流即(ji)可(ke)。

五、锂电池的维护电路

两(liang)节锂电(dian)(dian)(dian)(dian)池(chi)的(de)充放电(dian)(dian)(dian)(dian)维护(hu)电(dian)(dian)(dian)(dian)路如图一所示(shi)。由两(liang)个场效(xiao)应(ying)管(guan)(guan)和专用维护(hu)集成块S--8232组成，过充电(dian)(dian)(dian)(dian)控(kong)(kong)制(zhi)管(guan)(guan)FET2和过放电(dian)(dian)(dian)(dian)控(kong)(kong)制(zhi)管(guan)(guan)FET1串联于电(dian)(dian)(dian)(dian)路，由维护(hu)IC监视电(dian)(dian)(dian)(dian)池(chi)电(dian)(dian)(dian)(dian)压并(bing)中(zhong)(zhong)止控(kong)(kong)制(zhi)，当电(dian)(dian)(dian)(dian)池(chi)电(dian)(dian)(dian)(dian)压上升至4.2V时(shi)，过充电(dian)(dian)(dian)(dian)维护(hu)管(guan)(guan)FET1截(jie)(jie)止，中(zhong)(zhong)止充电(dian)(dian)(dian)(dian)。为防(fang)止误动作(zuo)，普(pu)通(tong)在(zai)外电(dian)(dian)(dian)(dian)路加有延时(shi)电(dian)(dian)(dian)(dian)容。当电(dian)(dian)(dian)(dian)池(chi)处(chu)于放电(dian)(dian)(dian)(dian)状态下，电(dian)(dian)(dian)(dian)池(chi)电(dian)(dian)(dian)(dian)压降至2.55V时(shi)，过放电(dian)(dian)(dian)(dian)控(kong)(kong)制(zhi)管(guan)(guan)FET1截(jie)(jie)止，中(zhong)(zhong)止向负载供电(dian)(dian)(dian)(dian)。

过电(dian)(dian)流(liu)(liu)维护是在(zai)当负(fu)载上有较大电(dian)(dian)流(liu)(liu)流(liu)(liu)过时，控制FET1使其截止，中止向(xiang)负(fu)载放电(dian)(dian)，目的是为了维护电(dian)(dian)池(chi)和场(chang)效应管。过电(dian)(dian)流(liu)(liu)检(jian)测(ce)是应用(yong)(yong)场(chang)效应管的导(dao)通(tong)电(dian)(dian)阻(zu)作(zuo)为检(jian)测(ce)电(dian)(dian)阻(zu)，监视它的电(dian)(dian)压降，当电(dian)(dian)压降超越设定值时就中止放电(dian)(dian)。在(zai)电(dian)(dian)路(lu)中普通(tong)还加有延(yan)时电(dian)(dian)路(lu)，以区分浪涌电(dian)(dian)流(liu)(liu)和短路(lu)电(dian)(dian)流(liu)(liu)。该电(dian)(dian)路(lu)功用(yong)(yong)完善，性能可(ke)靠，但专业性强，且专用(yong)(yong)集成块不易置办，业余(yu)爱好(hao)者不易仿制。

锂电池原理