電動車充電器的(de)有關知識

 

 

充電器的(de)分類：用有、無工頻(pin)（

50

赫茲）變壓器(qi)區分，可(ke)分為(wei)兩大類。貨運(yun)三輪充(chong)電器(qi)一

般使用(yong)帶工頻變(bian)壓器的充電機，體積(ji)大、重量大，費電，但(dan)是可靠，便宜；電動自行車(che)和電

摩(mo)則使(shi)用所謂開關電源式充電器，省(sheng)電，效率高(gao)，但(dan)是易壞。

 

 

 

 

 

開關電源(yuan)式充電器的(de)正(zheng)確操(cao)作(zuo)是：

充電時，

先插電池，

后加市電；

充足后，

先切斷市電，

后(hou)拔電(dian)(dian)池(chi)(chi)插頭(tou)。如果在充電(dian)(dian)時先(xian)拔電(dian)(dian)池(chi)(chi)插頭(tou)，特別(bie)是充電(dian)(dian)電(dian)(dian)流大（紅燈）時，非常容易損壞

充電器。

 

 

 

 

 

 

 

常用(yong)的(de)開關電源式(shi)充(chong)電器又分(fen)半橋(qiao)式(shi)和單激(ji)式(shi)兩大類，

單激(ji)類又分(fen)為正激(ji)式和反(fan)激(ji)式

兩類。半橋式成本(ben)高，性能(neng)好，常用于帶負脈沖的充(chong)電器；單激式成本(ben)低，市場占有率高。

 

 

 

 

 

 

 

關于負脈沖充電器

 

 

 

 

 

 

 

鉛酸電池已經有

100

多年的歷史了，

開(kai)始全球普遍(bian)沿引老(lao)的觀點和操作規程：

充、

放

電率為

0.1C(C

是電池容量

)

壽命較長。

美國人麥(mai)斯先生為解決快速充電問題，

1967

年向全世

界公布了他(ta)的(de)研(yan)究成果，用大(da)于(yu)

1C

率(lv)脈沖電(dian)(dian)(dian)(dian)流充(chong)電(dian)(dian)(dian)(dian)，充(chong)電(dian)(dian)(dian)(dian)間(jian)歇時對電(dian)(dian)(dian)(dian)池放(fang)電(dian)(dian)(dian)(dian)。放(fang)電(dian)(dian)(dian)(dian)有利于

消除極化、降低電解液(ye)溫度(du)、提高極板接受電荷的能力。

 

 

 

 

 

 

 

我國(guo)一些(xie)科技工作者在

1969

年(nian)前(qian)后，根(gen)據麥斯(si)先生的三定律(lv)制作成功了多種品牌的

快速充電機。

充電循環過程是：

大(da)電流脈沖充(chong)電→切斷充(chong)電通路→對電池短暫放電→停止放

電→接(jie)通充(chong)電通路→大電流脈沖充(chong)電??

 

 

 

 

 

 

 

 

2000

年前后(hou)，有人(ren)將這(zhe)一原理用到了電(dian)(dian)動(dong)車充電(dian)(dian)器中(zhong)，充電(dian)(dian)過程(cheng)中(zhong)，不切斷充電(dian)(dian)通

路，用(yong)小(xiao)電阻將電池短路瞬間，

進行放電(dian)。短路時由于不切斷充電(dian)通(tong)路，在充電(dian)通(tong)路中串(chuan)連

了電感。一般在

1

秒內短路

3

－

5

毫秒（

1

秒＝

1000

毫秒）

，由于電(dian)感里的電(dian)流不能跳變，

短

路時間短促，

可以保護充電器的電源轉換部分(fen)。

如(ru)果把充電電流方向叫正(zheng)，

放電自然為負了，

電動車(che)業就出現了名詞(ci)“負脈(mo)沖(chong)充電器”

，而且稱可以延長電池(chi)壽命等(deng)(deng)等(deng)(deng)。

 

 

 

 

 

 

 

關于三段式充電器

 

 

 

 

 

 

 

近幾年，

電(dian)動車普遍(bian)使用了所謂三段式(shi)充電(dian)器，

第一個(ge)階(jie)段叫恒流階(jie)段，

第二個階段

叫恒壓階段，

第三個階段叫(jiao)涓流階段。

從電(dian)子技術角度(du)針(zhen)對電(dian)池而言：

第一個階段叫充電限

流階段，

第二個階段叫高(gao)恒壓階段，

第(di)三個階段叫低恒壓(ya)階段比較(jiao)貼切。

第二階段和第三階

段轉換(huan)時，面板指示(shi)燈(deng)(deng)相應變換(huan)，大多數充(chong)電器(qi)第一、二階(jie)段是(shi)紅(hong)燈(deng)(deng)，第三階(jie)段變綠燈(deng)(deng)。第

二階段(duan)和第三階段(duan)的相互轉換是由充電(dian)電(dian)流(liu)決定(ding)的，

大于(yu)某電流進入第(di)一第(di)二(er)階段(duan)，

小于某

電流(liu)進入第三(san)階段(duan)。這個電流(liu)叫(jiao)轉換電流(liu)，也叫(jiao)轉折電流(liu)。

 

 

 

 

 

 

 

早期充電器，

包括名牌車配套的(de)充電器，雖(sui)然也變燈，

但實際是恒壓限流充電器，并

不(bu)是(shi)三階段充電(dian)器(qi)。一般這類就一個穩定電(dian)壓值(zhi)，

44.2V

左(zuo)右，對當(dang)時的高比重硫(liu)酸的電(dian)池

還湊合。

 

 

 

 

 

 

 

關于三(san)(san)段(duan)式充電器(qi)的(de)三(san)(san)個關鍵(jian)參數

 

 

 

 

 

 

 

第一個重要(yao)參數是涓流(liu)階段的低(di)恒(heng)壓值，

第二(er)個重要參數是第二(er)階段的(de)高恒(heng)壓值，

第

三(san)個(ge)重要參(can)數(shu)(shu)是轉換電(dian)流。這三(san)個(ge)重要參(can)數(shu)(shu)與電(dian)池(chi)數(shu)(shu)目(mu)有關(guan)，與電(dian)池(chi)的容量

Ah

有關，與溫

度有關，與(yu)電(dian)池種類有關。為了方便(bian)大家(jia)記憶，下面以最(zui)常見的(de)電(dian)動自行車（三塊

12V

串

聯的

10Ah

電池(chi)）所(suo)用的三段(duan)式(shi)充電器(qi)為(wei)例簡單介紹一(yi)下：

 

 

 

 

 

 

 

 

首先(xian)討論涓(juan)流階(jie)段(duan)的低恒壓值(zhi)，

參考電壓為

42.5V

左右。

此值高將使(shi)電池失水，

容易

使電池(chi)發(fa)熱變形；此值低不利于電池(chi)充足電。此值在南方要低于

41.5V

；膠體電池要低于

41.5V

，如(ru)在南方還要低一點兒。這(zhe)個(ge)參數是相對嚴格(ge)的，不可以大于參考值(zhi)。

 

 

 

 

 

 

 

其次討論第二(er)階段(duan)的(de)高(gao)恒壓(ya)值，參考電壓(ya)為

44.5V

左右(you)。此值高有利于快速充足電(dian)，

但是容易使電池失水，

充電(dian)后期電(dian)流(liu)下不(bu)來，

結(jie)果使電池發熱變(bian)形(xing)；

此值低不利于(yu)電(dian)池快速

充(chong)足電，有(you)利于(yu)向涓流階段轉換。這個(ge)值(zhi)雖(sui)然沒(mei)有(you)第一個(ge)值(zhi)那(nei)樣嚴格，但是也(ye)不(bu)要過高(gao)。

 

 

 

 

 

 

 

最后討論轉換電流，

參考電流為

300

毫安左右。

此值(zhi)高有利于電池(chi)壽命(ming)，

不容易發熱

本(ben)文介紹(shao)的是(shi)有關鋰電(dian)池組保(bao)護板均衡(heng)充(chong)電(dian)基本(ben)工作(zuo)原理，在(zai)采用單節鋰電(dian)池保(bao)護芯片設計的且具備(bei)均衡(heng)充(chong)電(dian)能(neng)力的鋰電(dian)池組保(bao)護板，示意圖如圖1所示。

其中：1為單節鋰離子電池；2為充電過電壓分流放電支路電阻；3 為分流放電支路控制用開關器件；4為過流檢測保護電阻；5為省略的鋰電池保護芯片及電路連接部分；6為單節鋰電池保護芯片(一般包括充電控制引腳CO,放電控制引腳DO，放電過電流及短路檢測引腳VM，電池正端VDD，電池負端VSS等)；7為充電過電壓保護信號經光耦隔離后形成并聯關系驅動主電路中充電控制用MOS管柵極；8為放電欠電壓、過流、短路保護信號經光耦隔離后形成串聯關系驅動主電路中放電控制用MOS管柵極；9為充電控制開關器件；10為放電控制開關器件；11為控制電路；12為主電路；13為分流放電支路。單節鋰電池保護芯片數目依據鋰電池組電(dian)池數目確定，串聯使用(yong)，分(fen)別對所對應(ying)單節鋰電(dian)池的充(chong)放(fang)電(dian)、過流、短(duan)路(lu)狀態進行(xing)保護(hu)(hu)(hu)。該系統在充(chong)電(dian)保護(hu)(hu)(hu)的同(tong)時，通(tong)過保護(hu)(hu)(hu)芯(xin)片控制分(fen)流放(fang)電(dian)支(zhi)路(lu)開關器(qi)件的通(tong)斷實(shi)現均(jun)衡充(chong)電(dian)，該方案(an)有別于傳統的在充(chong)電(dian)器(qi)端實(shi)現均(jun)衡充(chong)電(dian)的做(zuo)法，降(jiang)低了鋰電(dian)池組充(chong)電(dian)器(qi)設計應(ying)用(yong)的成本。

圖1 具備均(jun)衡充(chong)電能(neng)力的鋰(li)電池(chi)組保護板示(shi)意(yi)圖

當鋰電池組充電時，外接電源正負極分別接電池組正負極BAT+和BAT-兩端，充電電流流經電池組正極BAT+、電池組中單節鋰電池1～N、放電控制開關器件、充電控制開關器件、電池組負極BAT-,電流流向如圖2所示。
圖2 充電過程
系統中控制電路部分單節鋰電池保護芯片的充電過電壓保護控制信號經光耦隔離后并聯輸出，為主電路中充電開關器件的導通提供柵極電壓；如某一節或幾節鋰電池在充電過程中先進入過電壓保護狀態，則由過電壓保護信號控制并聯在單節鋰電池正(zheng)負極兩端的分流放(fang)電(dian)(dian)支路(lu)放(fang)電(dian)(dian)，同時將(jiang)串接在充電(dian)(dian)回(hui)路(lu)中的對應單體鋰電(dian)(dian)池斷(duan)離出(chu)充電(dian)(dian)回(hui)路(lu)。

鋰(li)(li)電(dian)(dian)(dian)(dian)池(chi)(chi)組(zu)串聯(lian)充(chong)(chong)電(dian)(dian)(dian)(dian)時，忽略單(dan)節電(dian)(dian)(dian)(dian)池(chi)(chi)容量差(cha)別的(de)影響，一般內(nei)阻(zu)較(jiao)小(xiao)的(de)電(dian)(dian)(dian)(dian)池(chi)(chi)先(xian)充(chong)(chong)滿。此時，相(xiang)應的(de)過電(dian)(dian)(dian)(dian)壓保(bao)(bao)護信(xin)號(hao)控(kong)制分(fen)(fen)流放電(dian)(dian)(dian)(dian)支(zhi)(zhi)(zhi)路(lu)(lu)的(de)開(kai)關(guan)器件閉(bi)合，在(zai)原電(dian)(dian)(dian)(dian)池(chi)(chi)兩端并聯(lian)上(shang)一個分(fen)(fen)流電(dian)(dian)(dian)(dian)阻(zu)。根(gen)據電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)PNGV等效電(dian)(dian)(dian)(dian)路(lu)(lu)模型，此時分(fen)(fen)流支(zhi)(zhi)(zhi)路(lu)(lu)電(dian)(dian)(dian)(dian)阻(zu)相(xiang)當(dang)于先(xian)充(chong)(chong)滿的(de)單(dan)節鋰(li)(li)電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)負(fu)載，該電(dian)(dian)(dian)(dian)池(chi)(chi)通(tong)過其放電(dian)(dian)(dian)(dian)，使電(dian)(dian)(dian)(dian)池(chi)(chi)端電(dian)(dian)(dian)(dian)壓維持在(zai)充(chong)(chong)滿狀態(tai)(tai)附近一個極小(xiao)的(de)范(fan)圍內(nei)。假設第1節鋰(li)(li)電(dian)(dian)(dian)(dian)池(chi)(chi)先(xian)充(chong)(chong)電(dian)(dian)(dian)(dian)完成，進入過電(dian)(dian)(dian)(dian)壓保(bao)(bao)護狀態(tai)(tai)，則主(zhu)電(dian)(dian)(dian)(dian)路(lu)(lu)及分(fen)(fen)流放電(dian)(dian)(dian)(dian)支(zhi)(zhi)(zhi)路(lu)(lu)中電(dian)(dian)(dian)(dian)流流向如圖3所示(shi)。當(dang)所有單(dan)節電(dian)(dian)(dian)(dian)池(chi)(chi)均充(chong)(chong)電(dian)(dian)(dian)(dian)進入過電(dian)(dian)(dian)(dian)壓保(bao)(bao)護狀態(tai)(tai)時，全部(bu)單(dan)節鋰(li)(li)電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓大小(xiao)在(zai)誤差(cha)范(fan)圍內(nei)完全相(xiang)等，各節保(bao)(bao)護芯片充(chong)(chong)電(dian)(dian)(dian)(dian)保(bao)(bao)護控(kong)制信(xin)號(hao)均變低，無(wu)法為主(zhu)電(dian)(dian)(dian)(dian)路(lu)(lu)中的(de)充(chong)(chong)電(dian)(dian)(dian)(dian)控(kong)制開(kai)關(guan)器件提供柵極偏壓，使其關(guan)斷，主(zhu)回路(lu)(lu)斷開(kai)，即實現均衡充(chong)(chong)電(dian)(dian)(dian)(dian)，充(chong)(chong)電(dian)(dian)(dian)(dian)過程完成。

圖3 分流均衡過程

當(dang)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)組放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)時，外接負(fu)(fu)(fu)載分(fen)別(bie)接電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)組正負(fu)(fu)(fu)極BAT+和(he)BAT-兩(liang)端(duan)，放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)流(liu)經電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)組負(fu)(fu)(fu)極BAT-、充電(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制(zhi)(zhi)開(kai)關(guan)(guan)器(qi)件、放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制(zhi)(zhi)開(kai)關(guan)(guan)器(qi)件、電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)組中(zhong)單(dan)(dan)節鋰電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)N～1和(he)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)組正極BAT+,電(dian)(dian)(dian)(dian)(dian)流(liu)流(liu)向如圖(tu)4所示。系統(tong)中(zhong)控(kong)(kong)制(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)部分(fen)單(dan)(dan)節鋰電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)保(bao)護芯片的(de)(de)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)欠電(dian)(dian)(dian)(dian)(dian)壓保(bao)護、過(guo)(guo)流(liu)和(he)短路(lu)(lu)保(bao)護控(kong)(kong)制(zhi)(zhi)信號經光耦隔離后串聯輸出，為主電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中(zhong)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)開(kai)關(guan)(guan)器(qi)件的(de)(de)導通提供柵極電(dian)(dian)(dian)(dian)(dian)壓;一旦電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)組在放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)過(guo)(guo)程中(zhong)遇(yu)到單(dan)(dan)節鋰電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)欠電(dian)(dian)(dian)(dian)(dian)壓或(huo)者過(guo)(guo)流(liu)和(he)短路(lu)(lu)等特殊情(qing)況，對應的(de)(de)單(dan)(dan)節鋰電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)保(bao)護控(kong)(kong)制(zhi)(zhi)信號變低(di)，無法(fa)為主電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中(zhong)的(de)(de)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制(zhi)(zhi)開(kai)關(guan)(guan)器(qi)件提供柵極偏壓，使(shi)其關(guan)(guan)斷(duan)，主回路(lu)(lu)斷(duan)開(kai)，即結束放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)使(shi)用過(guo)(guo)程。

圖4 放電過程

一般鋰電(dian)池(chi)采用恒流-恒壓(TAPER)型充(chong)電(dian)控制，恒壓充(chong)電(dian)時，充(chong)電(dian)電(dian)流近似指數規律減(jian)小。系(xi)統中充(chong)放電(dian)主回(hui)路的(de)開關器件可根(gen)據外部(bu)電(dian)路要求滿足的(de)最大工(gong)作電(dian)流和工(gong)作電(dian)壓選型。

控制電(dian)路的單節鋰(li)電(dian)池(chi)保(bao)護(hu)芯片可根(gen)據(ju)待(dai)保(bao)護(hu)的單節鋰(li)電(dian)池(chi)的電(dian)壓等級、保(bao)護(hu)延遲時間等選型。

單節電池兩端并接的放電支路電阻可根據鋰電池充電器的(de)充電電壓大(da)小(xiao)以及鋰(li)電池(chi)的(de)參數和(he)放電電流(liu)的(de)大(da)小(xiao)計算得(de)出。均(jun)衡(heng)電流(liu)應合理選(xuan)擇，如(ru)果(guo)太小(xiao)，均(jun)衡(heng)效果(guo)不明顯(xian)；如(ru)果(guo)太大(da)，系統的(de)能(neng)量(liang)損(sun)耗(hao)大(da)，均(jun)衡(heng)效率低，對鋰(li)電池(chi)組熱(re)管(guan)理要求高(gao)，一般電流(liu)大(da)小(xiao)可設計在(zai)50～100mA之間。

分(fen)流放電(dian)(dian)支路電(dian)(dian)阻(zu)(zu)(zu)可采用(yong)功率電(dian)(dian)阻(zu)(zu)(zu)或電(dian)(dian)阻(zu)(zu)(zu)網絡(luo)實現。這(zhe)里采用(yong)電(dian)(dian)阻(zu)(zu)(zu)網絡(luo)實現分(fen)流放電(dian)(dian)支路電(dian)(dian)阻(zu)(zu)(zu)較為合理，可以(yi)有(you)效消除(chu)電(dian)(dian)阻(zu)(zu)(zu)偏差的影響，此外，還能(neng)起(qi)到(dao)降低熱功耗的作用(yong)。