什么(me)是锂电池保护板-分(fen)析保护板构(gou)成(cheng)分(fen)类-组件功能分(fen)析等-KIA MOS管
信息(xi)来源:本站 日期:2018-01-16
一、保护板的(de)构成(cheng)
锂(li)电(dian)(dian)(dian)(dian)(dian)池(chi)(可充(chong)型)之所以需要保(bao)(bao)(bao)护(hu),是由(you)(you)它本(ben)身特(te)性(xing)决定的(de)。由(you)(you)于(yu)锂(li)电(dian)(dian)(dian)(dian)(dian)池(chi)本(ben)身的(de)材(cai)料决定了它不能被过(guo)充(chong)、过(guo)放、过(guo)流(liu)、短路(lu)及超高温充(chong)放电(dian)(dian)(dian)(dian)(dian),因此锂(li)电(dian)(dian)(dian)(dian)(dian)池(chi)锂(li)电(dian)(dian)(dian)(dian)(dian)组件总会跟着一(yi)块精(jing)致的(de)保(bao)(bao)(bao)护(hu)板和一(yi)片电(dian)(dian)(dian)(dian)(dian)流(liu)保(bao)(bao)(bao)险器出现(xian)。锂(li)电(dian)(dian)(dian)(dian)(dian)池(chi)的(de)保(bao)(bao)(bao)护(hu)功能通(tong)常由(you)(you)保(bao)(bao)(bao)护(hu)电(dian)(dian)(dian)(dian)(dian)路(lu)板和PTC协(xie)同(tong)完成(cheng),保(bao)(bao)(bao)护(hu)板是由(you)(you)电(dian)(dian)(dian)(dian)(dian)子电(dian)(dian)(dian)(dian)(dian)路(lu)组成(cheng),在-40℃至+85℃的(de)环境(jing)(jing)下(xia)时刻(ke)准确的(de)监视电(dian)(dian)(dian)(dian)(dian)芯的(de)电(dian)(dian)(dian)(dian)(dian)压和充(chong)放回路(lu)的(de)电(dian)(dian)(dian)(dian)(dian)流(liu),即时控制电(dian)(dian)(dian)(dian)(dian)流(liu)回路(lu)的(de)通(tong)断;PTC在高温环境(jing)(jing)下(xia)防(fang)止电(dian)(dian)(dian)(dian)(dian)池(chi)发(fa)生恶劣的(de)损坏。
保护板(ban)通常包括控(kong)制(zhi)(zhi)IC、MOS开(kai)(kai)关、电(dian)(dian)(dian)(dian)阻、电(dian)(dian)(dian)(dian)容及(ji)辅助器(qi)件NTC、ID存(cun)储(chu)器(qi)等。其(qi)中(zhong)(zhong)控(kong)制(zhi)(zhi)IC,在一切正常的(de)情况下控(kong)制(zhi)(zhi)MOS开(kai)(kai)关导(dao)通,使(shi)电(dian)(dian)(dian)(dian)芯与外(wai)电(dian)(dian)(dian)(dian)路(lu)(lu)沟通,而(er)当电(dian)(dian)(dian)(dian)芯电(dian)(dian)(dian)(dian)压或回路(lu)(lu)电(dian)(dian)(dian)(dian)流超过规定值时(shi),它立刻(ke)(数(shu)十(shi)毫秒)控(kong)制(zhi)(zhi)MOS开(kai)(kai)关关断,保护电(dian)(dian)(dian)(dian)芯的(de)安全。NTC是Negative temperaturecoefficient的(de)缩(suo)写(xie),意即负(fu)温度(du)系数(shu),在环境(jing)温度(du)升(sheng)高(gao)时(shi),其(qi)阻值降低,使(shi)用电(dian)(dian)(dian)(dian)设备(bei)或充电(dian)(dian)(dian)(dian)设备(bei)及(ji)时(shi)反应、控(kong)制(zhi)(zhi)内(nei)部(bu)中(zhong)(zhong)断而(er)停止充放电(dian)(dian)(dian)(dian)。ID 存(cun)储(chu)器(qi)常为单线接(jie)口存(cun)储(chu)器(qi),ID是Identification 的(de)缩(suo)写(xie)即身份识别的(de)意思,存(cun)储(chu)电(dian)(dian)(dian)(dian)池(chi)种类(lei)、生产日期(qi)等信(xin)息。可(ke)起(qi)到产品的(de)可(ke)追溯和应用的(de)限制(zhi)(zhi)。
一(yi)般要求在-25℃~85℃时(shi)Control(IC)检测控(kong)制电(dian)(dian)(dian)(dian)(dian)芯电(dian)(dian)(dian)(dian)(dian)压与(yu)(yu)充放(fang)电(dian)(dian)(dian)(dian)(dian)回(hui)路(lu)(lu)的工作(zuo)(zuo)电(dian)(dian)(dian)(dian)(dian)流(liu)、电(dian)(dian)(dian)(dian)(dian)压,在一(yi)切正(zheng)常(chang)情况下C-MOS开(kai)关管导通,使电(dian)(dian)(dian)(dian)(dian)芯与(yu)(yu)保护(hu)电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)板(ban)处(chu)于正(zheng)常(chang)工作(zuo)(zuo)状(zhuang)态(tai),而当电(dian)(dian)(dian)(dian)(dian)芯电(dian)(dian)(dian)(dian)(dian)压或回(hui)路(lu)(lu)中的工作(zuo)(zuo)电(dian)(dian)(dian)(dian)(dian)流(liu)超过控(kong)制IC中比较电(dian)(dian)(dian)(dian)(dian)路(lu)(lu)预设值时(shi),在15~30ms内(不同(tong)控(kong)制IC与(yu)(yu)C-MOS有不同(tong)的响应时(shi)间(jian)),将CMOS关断,即关闭电(dian)(dian)(dian)(dian)(dian)芯放(fang)电(dian)(dian)(dian)(dian)(dian)或充电(dian)(dian)(dian)(dian)(dian)回(hui)路(lu)(lu),以保证使用者与(yu)(yu)电(dian)(dian)(dian)(dian)(dian)芯的安全。
保护板主(zhu)要零件的功(gong)能介绍(shao)
R1:基准供电(dian)电(dian)阻(zu)(zu);与IC内部电(dian)阻(zu)(zu)构成分压(ya)电(dian)路,控制内部过充、过放电(dian)压(ya)比(bi)较(jiao)(jiao)器的(de)电(dian)平翻转;一(yi)般在阻(zu)(zu)值为330Ω、470Ω比(bi)较(jiao)(jiao)多(duo);当封装形式(即用标(biao)准元(yuan)(yuan)件的(de)长(zhang)(zhang)和宽来(lai)表示元(yuan)(yuan)件大小,如0402封装标(biao)识(shi)此元(yuan)(yuan)件的(de)长(zhang)(zhang)和宽分别为1.0mm和0.5mm)较(jiao)(jiao)大时,会(hui)用数字(zi)标(biao)识(shi)其阻(zu)(zu)值,如贴(tie)片(pian)电(dian)阻(zu)(zu)上数字(zi)标(biao)识(shi)473, 即表示其阻(zu)(zu)值为47000Ω即47KΩ(第三位(wei)数表示在前两位(wei)后面(mian)加0的(de)位(wei)数)。
R2:过(guo)(guo)流(liu)、短路检(jian)测(ce)电(dian)阻;通(tong)过(guo)(guo)检(jian)测(ce)VM端电(dian)压控制保护板的电(dian)流(liu) ,焊接不良、损坏会(hui)造成电(dian)池(chi)过(guo)(guo)流(liu) 、短路无保护,一般阻值(zhi)为1KΩ、2KΩ较多。
R3:ID识别电阻或NTC电阻(前(qian)面有(you)介绍)或两者都有(you)。
总结:电(dian)阻(zu)(zu)在保护板中为(wei)(wei)黑色贴片,用万用表(biao)可(ke)测其阻(zu)(zu)值(zhi),当封装较大时(shi)其阻(zu)(zu)值(zhi)会用数字表(biao)示,表(biao)示方(fang)法如上所述,当然电(dian)阻(zu)(zu)阻(zu)(zu)值(zhi)一般都有偏(pian)差,每个(ge)电(dian)阻(zu)(zu)都有精(jing)度(du)规格(ge),如10KΩ电(dian)阻(zu)(zu)规格(ge)为(wei)(wei)+/-5%精(jing)度(du)则其阻(zu)(zu)值(zhi)为(wei)(wei)9.5KΩ -10.5KΩ范围内都为(wei)(wei)合格(ge)。
C1、C2:由于(yu)电容两端电压(ya)不能突变(bian),起瞬(shun)间稳(wen)压(ya)和(he)(he)滤波(bo)作用。总结:电容在(zai)保护板中(zhong)为黄(huang)色贴片,封(feng)(feng)装形(xing)式(shi)0402较多(duo),也有少数0603封(feng)(feng)装(1.6mm长,0.8mm宽);用万用表检测其(qi)阻(zu)值一(yi)般为无穷大或(huo)MΩ级别;电容漏(lou)电会(hui)产生自(zi)耗(hao)电大,短(duan)路无自(zi)恢复现象。FUSE:普通(tong)FUSE或(huo)PTC(Positive Temperature Coefficient的(de)缩写,意思是正温(wen)度(du)系数);防止(zhi)不安全大电流和(he)(he)高(gao)温(wen)放电的(de)发生,其(qi)中(zhong)PTC有自(zi)恢复功能。
总(zong)结:FUSE在(zai)(zai)保护板(ban)中一(yi)般为白色(se)贴片,LITTE公(gong)司提供(gong)FUSE会在(zai)(zai)FUSE上标(biao)识字符D-T,字符表示意思为FUSE能承(cheng)受的额定电流,如(ru)表示D额定电流为0.25A,S为4A,T为5A等。
U1:控(kong)制IC;保护板所有(you)功能(neng)都是IC通过监(jian)视(shi)连接在(zai)VDD-VSS间(jian)的电压差(cha)及VM-VSS间(jian)的电压差(cha)而控(kong)制C-MOS执行开关(guan)动(dong)作来实现的。
Cout:过(guo)充(chong)控(kong)制(zhi)端(duan);通过(guo)MOS管T2栅极(ji)电压控(kong)制(zhi)MOS管的开关。
Dout:过放、过流、短路控制(zhi)端;通过MOS管(guan)T1栅(zha)极电压控制(zhi)MOS管(guan)的开(kai)关。
VM:过(guo)流、短路保(bao)护电(dian)压检测端;通过(guo)检测VM端的电(dian)压实现电(dian)路的过(guo)流、短路保(bao)护
(U(VM)=I*R(MOSFET))。
总结:IC在保护板中一般(ban)为(wei)(wei)6个管脚(jiao)(jiao)的(de)封(feng)装形式,其区(qu)别管脚(jiao)(jiao)的(de)方(fang)法为(wei)(wei):在封(feng)装体上标识黑(hei)点的(de)附近为(wei)(wei)第(di)1管脚(jiao)(jiao),然后逆时针旋转分(fen)别为(wei)(wei)第(di)2、3、4、5、6管脚(jiao)(jiao);如封(feng)装体上无黑(hei)点标识,则正看封(feng)装体上字(zi)符(fu)左(zuo)下为(wei)(wei)第(di)1管脚(jiao)(jiao),其余管脚(jiao)(jiao)逆时针类推)C-MOS:场效应开关(guan)管;保护功能(neng)的(de)实现(xian)者 ;连焊(han)、虚焊(han)、假焊(han)、击穿(chuan)时会(hui)造成电池无保护、无显示、输出电压低等不良现(xian)象。
总(zong)结:CMOS在保护板(ban)中一般为8个管脚(jiao)的封装形式,它时由两个MOS管构成,相当于(yu)两个开关,分(fen)别控制(zhi)过(guo)(guo)充保护和(he)过(guo)(guo)放(fang)、过(guo)(guo)流(liu)、短路保护;其管脚(jiao)区分(fen)方法和(he)IC一样。
在保(bao)护(hu)板正常情况(kuang)下,Vdd为(wei)(wei)高(gao)(gao)电平(ping),Vss、VM为(wei)(wei)低电平(ping),Dout、Cout为(wei)(wei)高(gao)(gao)电平(ping);当Vdd、Vss、VM任何一项参数(shu)变换时,Dout或Cout的电平(ping)将发生变化,此时MOSFET执行相应的动(dong)作(开、关电路),从而实现电路的保(bao)护(hu)和恢复功(gong)能(neng)。
1.NTC电阻测试:
用万(wan)用表直接(jie)测量NTC电阻值(zhi),再与《温度变化与NTC阻值(zhi)对(dui)照指导》对(dui)比。
2.识别电阻测(ce)试:
用万用表直接测(ce)量(liang)识别电阻(zu)值,再与《保护板重(zhong)要(yao)项目管理表》对比。
3.自耗电测试:
调恒(heng)流源为3.7V/500mA;万(wan)用(yong)(yong)表设置为uA档(dang),表笔插入uA接(jie)孔,然后与恒(heng)流源串联起来接(jie)保护(hu)板(ban)B+、B-如(ru)下图所示(shi):此时万(wan)用(yong)(yong)表的读数即(ji)为保护(hu)板(ban)的自耗电,如(ru)无读数用(yong)(yong)镊子或锡线短接(jie)B-、P-,激(ji)活(huo)电路(lu)。
4.短路(lu)保护(hu)测试:
电(dian)芯接(jie)(jie)到保(bao)护(hu)板B+、B-上,用(yong)镊子或锡线短接(jie)(jie)B-、P-,再短接(jie)(jie)P+、P-;短路后(hou)用(yong)万用(yong)表测保(bao)护(hu)板开路电(dian)压(如下图所示);反复短接(jie)(jie)3-5次,此时万用(yong)表读(du)数应(ying)与电(dian)芯一(yi)致,保(bao)护(hu)板应(ying)无冒烟、爆裂等(deng)现象。
5.内阻测试:
方法一、如右图连接好电路.用内(nei)阻(zu)测(ce)试仪(yi)测(ce)B-、P-间的(de)阻(zu)值(zhi)为(wei)RI,再(zai)测(ce)B+、P+间的(de)阻(zu)值(zhi)为(wei)R2,内(nei)阻(zu)测(ce)试仪(yi)本身(shen)内(nei)阻(zu)为(wei)R3,则保护板的(de)内(nei)阻(zu)为(wei)R1+R2-2R3.
方法(fa)二、
如右图(tu)接好电路(lu)。
用(yong)(yong)万(wan)用(yong)(yong)表分别测3+、P+间及B-、P-间电(dian)压。所得电(dian)压值即为(wei)保护板(ban)的(de)(de)内阻,因(yin)为(wei)电(dian)路中的(de)(de)电(dian)流为(wei)LA,根据欧姆(mu)定(ding)律:R=U/I。
如上图所(suo)示(shi)接好(hao)电(dian)(dian)(dian)路,按(an)(an)照重要(yao)项目管理(li)表(biao)设置(zhi)好(hao)锂易安(an)数据(ju),再(zai)按(an)(an)自动按(an)(an)钮,接好(hao)后按(an)(an)红表(biao)笔上的按(an)(an)钮进(jin)行(xing)测试(shi)(shi)。此时(shi)锂易安(an)测试(shi)(shi)仪的灯应逐次点亮,表(biao)示(shi)性能OK。按(an)(an)显示(shi)键检(jian)查测试(shi)(shi)数据(ju):‘Chg’表(biao)示(shi)过(guo)(guo)充(chong)保护电(dian)(dian)(dian)压(ya);‘Dis’表(biao)过(guo)(guo)放保护电(dian)(dian)(dian)压(ya);‘Ocur’表(biao)示(shi)过(guo)(guo)流保护电(dian)(dian)(dian)流。
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