电池保护板原理图细节分析及主要作用有哪些（附原理图）

电池保护板详解

电(dian)(dian)池(chi)保护(hu)(hu)板原理图，先看(kan)看(kan)池(chi)保护(hu)(hu)板概述，顾名思义锂电(dian)(dian)池(chi)保护(hu)(hu)板主(zhu)要是(shi)针对(dui)可(ke)充电(dian)(dian)（一般(ban)指(zhi)锂电(dian)(dian)池(chi)）起(qi)保护(hu)(hu)作(zuo)用的集成电(dian)(dian)路板。 锂电(dian)(dian)池(chi)（可(ke)充型）之(zhi)所(suo)以需要保护(hu)(hu)，是(shi)由它(ta)本身(shen)特性决定(ding)的。由于(yu)锂电(dian)(dian)池(chi)本身(shen)的材料(liao)决定(ding)了它(ta)不能被过(guo)充、过(guo)放、过(guo)流、短路及超(chao)高温充放电(dian)(dian)，因此锂电(dian)(dian)池(chi)锂电(dian)(dian)组(zu)件(jian)总会跟(gen)着一块带采(cai)样电(dian)(dian)阻的保护(hu)(hu)板和一片(pian)电(dian)(dian)流保险器出现。

锂(li)电(dian)(dian)(dian)池的(de)保(bao)护(hu)功能通常由保(bao)护(hu)电(dian)(dian)(dian)路板(ban)和(he)PTC等电(dian)(dian)(dian)流器件协(xie)同完(wan)成(cheng)(cheng)，保(bao)护(hu)板(ban)是由电(dian)(dian)(dian)子电(dian)(dian)(dian)路组(zu)成(cheng)(cheng)，在-40℃至+85℃的(de)环(huan)境(jing)下时刻准(zhun)确的(de)监(jian)视电(dian)(dian)(dian)芯的(de)电(dian)(dian)(dian)压和(he)充放回路的(de)电(dian)(dian)(dian)流，及(ji)时控制(zhi)电(dian)(dian)(dian)流回路的(de)通断；PTC在高温环(huan)境(jing)下防(fang)止电(dian)(dian)(dian)池发(fa)生恶劣(lie)的(de)损坏。

电池保护板原理图

电(dian)(dian)池保(bao)护(hu)(hu)板原理图(tu)解析如下文，普通锂电(dian)(dian)池保(bao)护(hu)(hu)板通常(chang)包括控(kong)制(zhi)IC、MOS开关(guan)、电(dian)(dian)阻、电(dian)(dian)容及辅助器件FUSE、PTC、NTC、ID、存储(chu)器等。其中控(kong)制(zhi)IC，在一切正常(chang)的情况下控(kong)制(zhi)MOS开关(guan)导通，使(shi)电(dian)(dian)芯(xin)与外电(dian)(dian)路(lu)导通，而当(dang)电(dian)(dian)芯(xin)电(dian)(dian)压或(huo)回路(lu)电(dian)(dian)流超过规定值(zhi)时，它立刻控(kong)制(zhi)MOS开关(guan)关(guan)断，保(bao)护(hu)(hu)电(dian)(dian)芯(xin)的安全。

在保护板正(zheng)常的情(qing)况下，Vdd为(wei)高电平(ping)(ping)，Vss,VM为(wei)低电平(ping)(ping)，DO、CO为(wei)高电平(ping)(ping)，当Vdd,Vss,VM任(ren)何一项(xiang)参数变换时，DO或CO端的电平(ping)(ping)将(jiang)发生(sheng)变化。

1、过充电检出电压：在(zai)通(tong)常状态下，Vdd逐渐提升至CO端由高电平 变为低(di)电平时VDD-VSS间(jian)电压。

2、过充(chong)电解(jie)除(chu)电压(ya)(ya)：在充(chong)电状态下，Vdd逐渐降低(di)至CO端由低(di)电平 变为(wei)高(gao)电平时(shi)VDD-VSS间电压(ya)(ya)。

3、过放电(dian)检出电(dian)压(ya)：通常状态(tai)下，Vdd逐渐降低至D O端由高电(dian)平 变为低电(dian)平时VDD- VSS间电(dian)压(ya)。

4、过(guo)放(fang)电(dian)(dian)解(jie)除(chu)电(dian)(dian)压：在(zai)过(guo)放(fang)电(dian)(dian)状(zhuang)态下，Vdd逐渐上(shang)升到(dao)DO端由低(di)电(dian)(dian)平 变(bian)为高电(dian)(dian)平时 VDD-VSS间(jian)电(dian)(dian)压 。

5、过电(dian)流1检出电(dian)压：在通(tong)常状(zhuang)态下，VM逐渐升(sheng)至DO由高电(dian)平(ping)(ping) 变(bian)为低电(dian)平(ping)(ping)时VM-VSS间电(dian)压。

6、过电(dian)流2检出电(dian)压：在通常状态下，VM从OV起以(yi)1ms以(yi)上4ms以(yi)下的速度升到 DO端由(you)高电(dian)平变为低电(dian)平时VM-VSS间电(dian)压。

7、负(fu)载短(duan)路检(jian)出电(dian)压：在通(tong)常状态下，VM以(yi)OV起以(yi)1μS以(yi)上50μS以(yi)下的速度升至DO端由(you)高(gao)电(dian)平变为低电(dian)平时VM-VSS间(jian)电(dian)压。

8、充电(dian)(dian)器检(jian)出(chu)电(dian)(dian)压(ya)：在过放电(dian)(dian)状态下(xia)，VM以OV逐渐下(xia)降(jiang)至DO由低(di)电(dian)(dian)平变为变为高电(dian)(dian)平时(shi)VM-VSS间(jian)电(dian)(dian)压(ya)。

9、通(tong)(tong)常(chang)(chang)工(gong)作时消耗(hao)电(dian)流：在(zai)通(tong)(tong)常(chang)(chang)状态下，流以VDD端子的电(dian)流（IDD）即为(wei)通(tong)(tong)常(chang)(chang)工(gong)作时消耗(hao)电(dian)流。

10、过放(fang)电(dian)消耗电(dian)流(liu)(liu)(liu)：在放(fang)电(dian)状(zhuang)态下，流(liu)(liu)(liu)经VDD端(duan)子的电(dian)流(liu)(liu)(liu)（IDD）即(ji)为过流(liu)(liu)(liu)放(fang)电(dian)消耗电(dian)流(liu)(liu)(liu)。

11、通常状态：电(dian)(dian)池电(dian)(dian)压(ya)(ya)在过放电(dian)(dian)检出电(dian)(dian)压(ya)(ya)以(yi)(yi)上（2.75V以(yi)(yi)上），过充(chong)(chong)电(dian)(dian)检出电(dian)(dian)压(ya)(ya)以(yi)(yi)下（4.3V以(yi)(yi)下），VM端子(zi)的(de)(de)电(dian)(dian)压(ya)(ya)在充(chong)(chong)电(dian)(dian)器检出电(dian)(dian)压(ya)(ya)以(yi)(yi)上，在过电(dian)(dian)流(liu)/检出电(dian)(dian)压(ya)(ya)以(yi)(yi)下（OV）的(de)(de)情况(kuang)下，IC通过监视连接在VDD-VSS间的(de)(de)电(dian)(dian)压(ya)(ya)差及VM-VSS间的(de)(de)电(dian)(dian)压(ya)(ya)差而控制MOS管(guan)(guan)，DO、CO端都为高(gao)电(dian)(dian)平，MOS管(guan)(guan)处导通状态，这时(shi)可以(yi)(yi)自由的(de)(de)充(chong)(chong)电(dian)(dian)和放电(dian)(dian)；

当电(dian)池被充(chong)电(dian)使电(dian)压(ya)(ya)超(chao)过设定值VC(4.25-4.35V)后，VD1翻转使Cout变(bian)为低电(dian)平，T1截(jie)止(zhi)，充(chong)电(dian)停止(zhi)，当电(dian)池电(dian)压(ya)(ya)回落至VCR(3.8-4.1V)时，Cout变(bian)为高电(dian)平，T1导通充(chong)电(dian)继(ji)续， VCR小于VC一(yi)个定值，以防止(zhi)电(dian)流(liu)频(pin)繁跳(tiao)变(bian)。

当(dang)电(dian)池电(dian)压因放电(dian)而降(jiang)低至(zhi)设定值VD（2.3-2.5V）时， VD2翻转，以IC内部(bu)固定的(de)短(duan)时间延时后，使Dout变(bian)为低电(dian)平，T2截止(zhi)，放电(dian)停止(zhi)。

附上电池保护板原理图

当电(dian)路(lu)放电(dian)电(dian)流(liu)(liu)超过(guo)设定值或输出被短(duan)路(lu)时，过(guo)流(liu)(liu)、短(duan)路(lu)检测电(dian)路(lu)动作，使MOS管（T2）关断，电(dian)流(liu)(liu)截止。

该保护(hu)回(hui)(hui)路(lu)由两(liang)个MOSFET（T1、T2）和一个控制(zhi)(zhi)IC（N1）外加一些阻(zu)容元(yuan)件构成。控制(zhi)(zhi)IC负责监测电(dian)(dian)(dian)池电(dian)(dian)(dian)压与回(hui)(hui)路(lu)电(dian)(dian)(dian)流(liu)，并控制(zhi)(zhi)两(liang)个MOSFET的(de)栅极，MOSFET在电(dian)(dian)(dian)路(lu)中起开关作用(yong)，分(fen)(fen)别控制(zhi)(zhi)着(zhe)充电(dian)(dian)(dian)回(hui)(hui)路(lu)与放电(dian)(dian)(dian)回(hui)(hui)路(lu)的(de)导通与关断，C2为延(yan)时电(dian)(dian)(dian)容，该电(dian)(dian)(dian)路(lu)具有(you)过(guo)充电(dian)(dian)(dian)保护(hu)、过(guo)放电(dian)(dian)(dian)保护(hu)、过(guo)电(dian)(dian)(dian)流(liu)保护(hu)与短(duan)路(lu)保护(hu)功能(neng)，其工作原(yuan)理分(fen)(fen)析如(ru)下：

1、短路(lu)保(bao)护(hu)

电(dian)(dian)(dian)(dian)(dian)池在对负(fu)载放(fang)电(dian)(dian)(dian)(dian)(dian)过程中，若回路电(dian)(dian)(dian)(dian)(dian)流(liu)大到使U>0.9V（该值由控制IC决定，不同的(de)(de)IC有不同的(de)(de)值）时(shi)，控制IC则判(pan)(pan)断(duan)为(wei)负(fu)载短路，其“DO”脚将(jiang)迅速由高电(dian)(dian)(dian)(dian)(dian)压转变为(wei)零电(dian)(dian)(dian)(dian)(dian)压，使T2由导通(tong)转为(wei)关断(duan)，从而(er)切断(duan)放(fang)电(dian)(dian)(dian)(dian)(dian)回路，起(qi)到短路保(bao)护作用(yong)。短路保(bao)护的(de)(de)延时(shi)时(shi)间极短，通(tong)常(chang)小(xiao)于7微(wei)秒。其工(gong)作原理与(yu)过电(dian)(dian)(dian)(dian)(dian)流(liu)保(bao)护类似，只是判(pan)(pan)断(duan)方法(fa)不同，保(bao)护延时(shi)时(shi)间也(ye)不一样。

2、过放电保(bao)护

电(dian)池(chi)(chi)在对外部负载(zai)放电(dian)过(guo)程中，其(qi)电(dian)压会(hui)随着放电(dian)过(guo)程逐渐降低，当电(dian)池(chi)(chi)电(dian)压降至2.5V时(shi)，其(qi)容量已被(bei)完(wan)全(quan)放光，此(ci)时(shi)如果让(rang)电(dian)池(chi)(chi)继续对负载(zai)放电(dian)，将造成电(dian)池(chi)(chi)的永久性损坏。

在(zai)电(dian)(dian)(dian)(dian)池(chi)放电(dian)(dian)(dian)(dian)过程(cheng)中，当(dang)控制(zhi)IC检测到(dao)电(dian)(dian)(dian)(dian)池(chi)电(dian)(dian)(dian)(dian)压(ya)低(di)于(yu)2.3V（该值(zhi)由控制(zhi)IC决定，不同的IC有不同的值(zhi)）时，其“DO”脚将由高电(dian)(dian)(dian)(dian)压(ya)转变为(wei)零(ling)电(dian)(dian)(dian)(dian)压(ya)，使(shi)T2由导通转为(wei)关断(duan)，从而(er)切(qie)断(duan)了放电(dian)(dian)(dian)(dian)回路(lu)，使(shi)电(dian)(dian)(dian)(dian)池(chi)无法(fa)再对负载(zai)进行放电(dian)(dian)(dian)(dian)，起(qi)到(dao)过放电(dian)(dian)(dian)(dian)保(bao)护作用(yong)。而(er)此时由于(yu)T2自带的体二极管(guan)VD2的存在(zai)，充(chong)电(dian)(dian)(dian)(dian)器可以通过该二极管(guan)对电(dian)(dian)(dian)(dian)池(chi)进行充(chong)电(dian)(dian)(dian)(dian)。

3、过充电保(bao)护

锂离(li)子电(dian)(dian)池要求的充(chong)电(dian)(dian)方式为恒流/恒压，在充(chong)电(dian)(dian)初(chu)期，为恒流充(chong)电(dian)(dian)，随着充(chong)电(dian)(dian)过程，电(dian)(dian)压会上升到(dao)4.2V(根(gen)据正(zheng)极材(cai)料不同，有的电(dian)(dian)池要求恒压值为4.1V)，转为恒压充(chong)电(dian)(dian)，直至电(dian)(dian)流越来(lai)越小(xiao)。

电(dian)(dian)(dian)(dian)(dian)池(chi)(chi)在被(bei)充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)过程中，如果充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)器电(dian)(dian)(dian)(dian)(dian)路失去控制，会(hui)使电(dian)(dian)(dian)(dian)(dian)池(chi)(chi)电(dian)(dian)(dian)(dian)(dian)压(ya)超过4.2V后继续(xu)恒流充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)，此时(shi)电(dian)(dian)(dian)(dian)(dian)池(chi)(chi)电(dian)(dian)(dian)(dian)(dian)压(ya)仍会(hui)继续(xu)上升，当电(dian)(dian)(dian)(dian)(dian)池(chi)(chi)电(dian)(dian)(dian)(dian)(dian)压(ya)被(bei)充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)至超过4.3V时(shi)，电(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的化学(xue)副(fu)反应将加剧，会(hui)导(dao)致电(dian)(dian)(dian)(dian)(dian)池(chi)(chi)损坏或出现安全问题。

在(zai)带有保护(hu)电(dian)(dian)(dian)(dian)路的(de)(de)电(dian)(dian)(dian)(dian)池中，当控制IC检测到(dao)电(dian)(dian)(dian)(dian)池电(dian)(dian)(dian)(dian)压达到(dao)4.28V（该(gai)值由控制IC决定，不同的(de)(de)IC有不同的(de)(de)值）时(shi)，其“CO”脚将由高电(dian)(dian)(dian)(dian)压转变为(wei)(wei)零电(dian)(dian)(dian)(dian)压，使(shi)T1由导通(tong)转为(wei)(wei)关断，从而切断了充(chong)电(dian)(dian)(dian)(dian)回路，使(shi)充(chong)电(dian)(dian)(dian)(dian)器无法再对电(dian)(dian)(dian)(dian)池进行(xing)充(chong)电(dian)(dian)(dian)(dian)，起到(dao)过充(chong)电(dian)(dian)(dian)(dian)保护(hu)作用。而此时(shi)由于T1自带的(de)(de)体二(er)(er)极(ji)管VD1的(de)(de)存在(zai)，电(dian)(dian)(dian)(dian)池可以通(tong)过该(gai)二(er)(er)极(ji)管对外部负载进行(xing)放电(dian)(dian)(dian)(dian)。

在控(kong)制IC检(jian)测到(dao)电(dian)池电(dian)压超(chao)过4.28V至发出关断(duan)T1信(xin)号之间(jian)，还(hai)有(you)一段(duan)延时(shi)时(shi)间(jian)，该延时(shi)时(shi)间(jian)的长短由C2决(jue)定，通常(chang)设为(wei)1秒左右，以避免因干扰而造成误判断(duan)。

4、过电流保(bao)护

由(you)于锂离子电(dian)池(chi)(chi)的化学特(te)性(xing)，电(dian)池(chi)(chi)生产厂(chang)家(jia)规定(ding)了其放电(dian)电(dian)流(liu)最大不能超过2C（C=电(dian)池(chi)(chi)容量/小时），当电(dian)池(chi)(chi)超过2C电(dian)流(liu)放电(dian)时，将会导致(zhi)电(dian)池(chi)(chi)的永久性(xing)损(sun)坏(huai)或出现(xian)安全问题。

电(dian)(dian)(dian)池(chi)在(zai)对(dui)负载正常放电(dian)(dian)(dian)过程(cheng)中(zhong)，放电(dian)(dian)(dian)电(dian)(dian)(dian)流在(zai)经过串联(lian)的(de)2个MOSFET时(shi)，由(you)(you)于MOSFET的(de)导通阻(zu)抗，会在(zai)其两端(duan)产生一个电(dian)(dian)(dian)压(ya)，该(gai)电(dian)(dian)(dian)压(ya)值U=I*RDS*2, RDS为单(dan)个MOSFET导通阻(zu)抗，控制(zhi)IC上的(de)“V-”脚对(dui)该(gai)电(dian)(dian)(dian)压(ya)值进(jin)行检测，若(ruo)负载因某种原因导致(zhi)异常，使(shi)回路(lu)(lu)(lu)电(dian)(dian)(dian)流增大，当回路(lu)(lu)(lu)电(dian)(dian)(dian)流大到使(shi)U>0.1V（该(gai)值由(you)(you)控制(zhi)IC决定，不同(tong)的(de)IC有不同(tong)的(de)值）时(shi)，其“DO”脚将由(you)(you)高(gao)电(dian)(dian)(dian)压(ya)转变为零电(dian)(dian)(dian)压(ya)，使(shi)T2由(you)(you)导通转为关断(duan)，从(cong)而切断(duan)了(le)放电(dian)(dian)(dian)回路(lu)(lu)(lu)，使(shi)回路(lu)(lu)(lu)中(zhong)电(dian)(dian)(dian)流为零，起到过电(dian)(dian)(dian)流保护作(zuo)用。

5、正常状态

在正常(chang)状态(tai)下(xia)电(dian)(dian)路中N1的(de)(de)“CO”与“DO”脚(jiao)都输出(chu)高(gao)电(dian)(dian)压(ya)，两个MOSFET都处于导(dao)通(tong)(tong)状态(tai)，电(dian)(dian)池(chi)可以自由地(di)进行充电(dian)(dian)和放(fang)电(dian)(dian)，由于MOSFET的(de)(de)导(dao)通(tong)(tong)阻抗很小，通(tong)(tong)常(chang)小于30毫欧，因此其导(dao)通(tong)(tong)电(dian)(dian)阻对电(dian)(dian)路的(de)(de)性能(neng)影响很小。

电池保护板的主要作用

1、电(dian)(dian)(dian)流(liu)(liu)保护：它主要体现在工作电(dian)(dian)(dian)流(liu)(liu)与过电(dian)(dian)(dian)流(liu)(liu)使开关MOS断开从(cong)而保护电(dian)(dian)(dian)池(chi)组或负(fu)载。

2、电(dian)压(ya)保护：过充(chong)，过放，这要(yao)根据电(dian)池(chi)的材料不同而(er)有(you)所改(gai)变，过充(chong)保护，在我们以往的单节电(dian)池(chi)保护电(dian)压(ya)都会高出(chu)电(dian)池(chi)充(chong)饱电(dian)压(ya)50~150mV。但是(shi)动力(li)电(dian)池(chi)不一样，如果你要(yao)想延长电(dian)池(chi)寿命，你的保护电(dian)压(ya)就选择电(dian)池(chi)的充(chong)饱电(dian)压(ya)，甚至还要(yao)比此电(dian)压(ya)还低些。

3、短(duan)路保护(hu)(hu)：严(yan)格来讲，他是一个电压比较型(xing)的(de)保护(hu)(hu)，也就是讲是用电压的(de)比较直接(jie)关断或驱动的(de)，不要经(jing)过多余的(de)处(chu)理。

4、温(wen)度保(bao)护(hu)：一般在(zai)智能电池(chi)上都(dou)会用到(dao)，也是不(bu)可(ke)少的。但往往它的完美总会带来另一方面的不(bu)足。我们主要是检测电池(chi)的温(wen)度来断(duan)开总开关来保(bao)护(hu)电池(chi)本身或(huo)负载。

5、自耗电量(liang), 这(zhei)个参数是越(yue)小越(yue)好，最理想的状态是为零，但不可能做到这(zhei)一点(dian)。

6、MOS保护：主(zhu)要是(shi)MOS的(de)电压，电流与温度。当(dang)然就是(shi)牵扯到(dao)MOS管的(de)选型了(le)。MOS的(de)耐(nai)压当(dang)然要超过电池组的(de)电压，这是(shi)必须的(de)。

7、均(jun)衡：均(jun)衡这一(yi)块(kuai)是(shi)此(ci)文章的论述的重(zhong)点(dian)。目(mu)前最通用(yong)的均(jun)衡方式分为两种(zhong)，一(yi)种(zhong)就是(shi)耗能(neng)式的，另(ling)一(yi)种(zhong)就是(shi)转能(neng)式的。

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