電動車充(chong)電器的有關知識

 

 

充電(dian)器的分(fen)類：用有、無工頻(pin)（

50

赫(he)茲(zi)）變壓(ya)器區分，可分為兩(liang)大類。貨運(yun)三輪充電(dian)器一

般使用帶工(gong)頻變壓器的充電機，體積大、重量大，費電，但是(shi)可靠，便宜；電動(dong)自行車和電

摩則(ze)使用所謂(wei)開關電(dian)源式充電(dian)器，省電(dian)，效率高，但是易壞。

 

 

 

 

 

開關電源式充電器(qi)的正確操作(zuo)是：

充電時，

先插電池，

后加市電；

充足后，

先切斷市電，

后拔電(dian)池插頭(tou)。如果在充(chong)電(dian)時(shi)先拔電(dian)池插頭(tou)，特別是充(chong)電(dian)電(dian)流大（紅燈）時(shi)，非常容易損壞

充電器。

 

 

 

 

 

 

 

常(chang)用的開關電(dian)源(yuan)式(shi)充電(dian)器(qi)又分半橋式(shi)和單激式(shi)兩大類，

單(dan)激(ji)類又(you)分為(wei)正激(ji)式和反激(ji)式

兩(liang)類。半橋(qiao)式(shi)成本(ben)高，性能(neng)好，常用于帶負脈沖的充電器(qi)；單激式(shi)成本(ben)低(di)，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，

開始全(quan)球普遍(bian)沿引老的觀點和操作(zuo)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(si)先生(sheng)為解決快速充(chong)電(dian)問(wen)題，

1967

年向全世

界公布(bu)了他的研究成果，用大(da)于

1C

率脈沖電(dian)(dian)流充電(dian)(dian)，充電(dian)(dian)間歇時對電(dian)(dian)池放電(dian)(dian)。放電(dian)(dian)有利于

消除(chu)極化(hua)、降低電解液溫度(du)、提高極板接受電荷的能力。

 

 

 

 

 

 

 

我國一些科技工作者在

1969

年前后，根據麥斯先生(sheng)的三(san)定律制作成(cheng)功了多(duo)種品牌的

快速充電機。

充電循環過程是：

大電流脈(mo)沖充電→切斷(duan)充電通路→對電池短暫(zan)放電→停止放

電→接通充(chong)電通路→大電流脈沖充(chong)電??

 

 

 

 

 

 

 

 

2000

年前后，有人(ren)將這一原(yuan)理用到了電動車充(chong)電器中，充(chong)電過程中，不切斷充(chong)電通

路，用小電(dian)阻將電(dian)池短路瞬間，

進(jin)行放電(dian)。短路時由于不切斷充電(dian)通路，在充電(dian)通路中(zhong)串連

了電感。一般在

1

秒內短路

3

－

5

毫秒（

1

秒＝

1000

毫秒）

，由于電(dian)(dian)感(gan)里的電(dian)(dian)流不能跳(tiao)變，

短

路時間短促，

可以保護充電(dian)器的(de)電(dian)源(yuan)轉換部(bu)分。

如果把(ba)充電電流方向(xiang)叫正，

放電自然為負了，

電動(dong)車業就出現(xian)了(le)名詞“負脈(mo)沖(chong)充電器”

，而且稱可(ke)以延長電(dian)池壽命等等。

 

 

 

 

 

 

 

關于三段式充電器

 

 

 

 

 

 

 

近幾年，

電(dian)(dian)動(dong)車普(pu)遍使用了所謂三段式充電(dian)(dian)器，

第一個(ge)階(jie)段(duan)叫(jiao)恒(heng)流階(jie)段(duan)，

第二個階段

叫恒壓階段，

第三個階(jie)段(duan)叫涓流階(jie)段(duan)。

從電(dian)子技術角度針對電(dian)池而言(yan)：

第一個階段叫充電限

流階段，

第(di)二個階段叫高(gao)恒(heng)壓階段，

第三(san)個階(jie)段(duan)叫低恒壓階(jie)段(duan)比較貼切。

第二階段和第三階

段(duan)轉換時，面板指示燈相應變(bian)換，大多數充電(dian)器第一(yi)、二階(jie)段(duan)是(shi)紅(hong)燈，第三階(jie)段(duan)變(bian)綠(lv)燈。第

二階段和第(di)三階段的相互轉(zhuan)換(huan)是由(you)充電(dian)(dian)電(dian)(dian)流決(jue)定的，

大于某電流進入第一第二(er)階段(duan)，

小于某

電(dian)(dian)流(liu)進入第(di)三階段(duan)。這個(ge)電(dian)(dian)流(liu)叫(jiao)轉換電(dian)(dian)流(liu)，也叫(jiao)轉折電(dian)(dian)流(liu)。

 

 

 

 

 

 

 

早期充電器，

包括名牌車(che)配套的充(chong)電器，雖(sui)然也變燈，

但實際是恒壓限流充電器(qi)，并

不是三階段充電(dian)器。一般這類就一個穩定電(dian)壓值，

44.2V

左右，對當時(shi)的高(gao)比重硫酸(suan)的電池(chi)

還湊合。

 

 

 

 

 

 

 

關(guan)于三段式充電器的(de)三個關(guan)鍵參數

 

 

 

 

 

 

 

第一個(ge)重要參數是(shi)涓流階段的低(di)恒(heng)壓值，

第二個重(zhong)要參(can)數是第二階段的高(gao)恒壓(ya)值，

第

三個重(zhong)要(yao)參(can)數(shu)(shu)是轉換(huan)電(dian)流。這三個重(zhong)要(yao)參(can)數(shu)(shu)與電(dian)池數(shu)(shu)目有關，與電(dian)池的容量

Ah

有關，與溫

度有(you)(you)關，與(yu)電池種類有(you)(you)關。為了方便大家記憶，下面(mian)以最常見的電動自(zi)行車(che)（三塊(kuai)

12V

串

聯的

10Ah

電池）所用的三段(duan)式充電器為(wei)例(li)簡單介紹一(yi)下：

 

 

 

 

 

 

 

 

首(shou)先討論涓(juan)流階(jie)段的(de)低(di)恒壓值，

參考電壓為

42.5V

左右。

此(ci)值高將(jiang)使電(dian)池失水(shui)，

容易

使電池發熱變形；此值(zhi)低不利于電池充足電。此值(zhi)在南方要低于

41.5V

；膠體電池要低于

41.5V

，如在(zai)南方還要低一(yi)點兒。這個參(can)(can)數是(shi)相對嚴格的，不可以大于參(can)(can)考(kao)值。

 

 

 

 

 

 

 

其(qi)次討(tao)論第二階段的高恒壓值，參考電壓為

44.5V

左右。此值高有利于快(kuai)速充足(zu)電，

但是容(rong)易使電池失水，

充電后期電流下(xia)不來(lai)，

結果使(shi)電池(chi)發熱變形(xing)；

此值低不利(li)于電(dian)池快速

充足電，有利于向涓流階段轉換。這個值雖然沒(mei)有第(di)一個值那樣嚴格(ge)，但是(shi)也不要過高。

 

 

 

 

 

 

 

最后討論轉換電流，

參考電流為

300

毫安左右。

此值高(gao)有利于電池壽命，

不容易發熱

本文(wen)介紹(shao)的(de)是(shi)有關(guan)鋰電(dian)池(chi)組保護板均衡(heng)充電(dian)基本工(gong)作原(yuan)理，在(zai)采用單節鋰電(dian)池(chi)保護芯片設計的(de)且具(ju)備均衡(heng)充電(dian)能(neng)力的(de)鋰電(dian)池(chi)組保護板，示意圖(tu)如圖(tu)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(shi)用，分(fen)別(bie)對所對應單節鋰電(dian)池的(de)(de)充放電(dian)、過流、短路狀態進行(xing)保護(hu)。該系(xi)統在(zai)充電(dian)保護(hu)的(de)(de)同時(shi)，通過保護(hu)芯片控制(zhi)分(fen)流放電(dian)支(zhi)路開關器(qi)件的(de)(de)通斷(duan)實(shi)現均衡充電(dian)，該方案有(you)別(bie)于傳統的(de)(de)在(zai)充電(dian)器(qi)端實(shi)現均衡充電(dian)的(de)(de)做法，降低(di)了鋰電(dian)池組充電(dian)器(qi)設計應用的(de)(de)成本(ben)。

圖1 具備均衡充電(dian)(dian)能(neng)力的鋰電(dian)(dian)池(chi)組保護(hu)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負極(ji)兩端(duan)的分流放(fang)電(dian)支路放(fang)電(dian)，同時將串接在(zai)充電(dian)回(hui)路中的對應(ying)單體鋰電(dian)池斷離出充電(dian)回(hui)路。

鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組串聯(lian)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，忽(hu)略單(dan)節(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)容量(liang)差(cha)別的(de)(de)影響，一(yi)般內阻較小的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)先充(chong)(chong)(chong)(chong)滿。此(ci)時(shi)，相(xiang)應的(de)(de)過(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)護信(xin)號(hao)控(kong)制分(fen)流放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)支路(lu)的(de)(de)開(kai)關器件閉合，在(zai)原電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)兩端(duan)并聯(lian)上一(yi)個分(fen)流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻。根據電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)PNGV等(deng)效電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)模型，此(ci)時(shi)分(fen)流支路(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻相(xiang)當于(yu)先充(chong)(chong)(chong)(chong)滿的(de)(de)單(dan)節(jie)(jie)鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)負(fu)載，該電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)通過(guo)(guo)(guo)其放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)維持在(zai)充(chong)(chong)(chong)(chong)滿狀態(tai)附近一(yi)個極(ji)小的(de)(de)范圍(wei)內。假設第1節(jie)(jie)鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)先充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)完成，進入(ru)過(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)護狀態(tai)，則主(zhu)(zhu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)及分(fen)流放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)支路(lu)中電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流流向如圖3所示(shi)。當所有單(dan)節(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)均充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)進入(ru)過(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)護狀態(tai)時(shi)，全(quan)部(bu)單(dan)節(jie)(jie)鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)大小在(zai)誤差(cha)范圍(wei)內完全(quan)相(xiang)等(deng)，各節(jie)(jie)保(bao)護芯(xin)片充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)保(bao)護控(kong)制信(xin)號(hao)均變低(di)，無法為主(zhu)(zhu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)中的(de)(de)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)制開(kai)關器件提供柵極(ji)偏(pian)壓(ya)，使其關斷，主(zhu)(zhu)回路(lu)斷開(kai)，即(ji)實現均衡充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)過(guo)(guo)(guo)程完成。

圖3 分流均衡過程

當(dang)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)時(shi)，外接負載(zai)分別接電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)正(zheng)負極(ji)BAT+和(he)(he)BAT-兩(liang)端，放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)流(liu)(liu)(liu)經(jing)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)負極(ji)BAT-、充電(dian)(dian)(dian)(dian)控(kong)(kong)制開關(guan)(guan)器件(jian)、放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)控(kong)(kong)制開關(guan)(guan)器件(jian)、電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)中單(dan)(dan)(dan)節鋰(li)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)N～1和(he)(he)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)正(zheng)極(ji)BAT+,電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)流(liu)(liu)(liu)向(xiang)如圖(tu)4所示(shi)。系統中控(kong)(kong)制電(dian)(dian)(dian)(dian)路(lu)(lu)部分單(dan)(dan)(dan)節鋰(li)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)保(bao)護芯(xin)片的(de)(de)(de)放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)欠電(dian)(dian)(dian)(dian)壓(ya)(ya)保(bao)護、過(guo)(guo)流(liu)(liu)(liu)和(he)(he)短(duan)路(lu)(lu)保(bao)護控(kong)(kong)制信號(hao)經(jing)光耦隔離后(hou)串聯輸出，為(wei)主(zhu)電(dian)(dian)(dian)(dian)路(lu)(lu)中放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)開關(guan)(guan)器件(jian)的(de)(de)(de)導通提(ti)供柵極(ji)電(dian)(dian)(dian)(dian)壓(ya)(ya);一旦(dan)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)在放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)過(guo)(guo)程中遇(yu)到單(dan)(dan)(dan)節鋰(li)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)欠電(dian)(dian)(dian)(dian)壓(ya)(ya)或者過(guo)(guo)流(liu)(liu)(liu)和(he)(he)短(duan)路(lu)(lu)等(deng)特殊情況，對應的(de)(de)(de)單(dan)(dan)(dan)節鋰(li)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)保(bao)護控(kong)(kong)制信號(hao)變(bian)低，無法為(wei)主(zhu)電(dian)(dian)(dian)(dian)路(lu)(lu)中的(de)(de)(de)放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)控(kong)(kong)制開關(guan)(guan)器件(jian)提(ti)供柵極(ji)偏壓(ya)(ya)，使其關(guan)(guan)斷，主(zhu)回路(lu)(lu)斷開，即結(jie)束放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)使用(yong)過(guo)(guo)程。

圖4 放電過程

一般鋰電(dian)池采用恒(heng)流-恒(heng)壓(TAPER)型充(chong)(chong)電(dian)控制，恒(heng)壓充(chong)(chong)電(dian)時，充(chong)(chong)電(dian)電(dian)流近似指數規律減小(xiao)。系(xi)統(tong)中充(chong)(chong)放電(dian)主回路(lu)的(de)開(kai)關器件(jian)可根(gen)據(ju)外部(bu)電(dian)路(lu)要求滿(man)足(zu)的(de)最大工作電(dian)流和(he)工作電(dian)壓選型。

控制電路的(de)單節鋰電池保護芯片可根據待保護的(de)單節鋰電池的(de)電壓(ya)等級、保護延遲(chi)時(shi)間(jian)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)(de)充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)壓大(da)(da)小以及鋰電(dian)(dian)(dian)池的(de)(de)參數和放(fang)電(dian)(dian)(dian)電(dian)(dian)(dian)流的(de)(de)大(da)(da)小計(ji)算得出。均衡電(dian)(dian)(dian)流應合理(li)選擇，如果(guo)太小，均衡效(xiao)果(guo)不明(ming)顯(xian)；如果(guo)太大(da)(da)，系統的(de)(de)能量損耗(hao)大(da)(da)，均衡效(xiao)率(lv)低，對(dui)鋰電(dian)(dian)(dian)池組熱管理(li)要求高(gao)，一般電(dian)(dian)(dian)流大(da)(da)小可設計(ji)在(zai)50～100mA之間(jian)。

分(fen)流(liu)放電支路電阻可采用(yong)功率電阻或(huo)電阻網絡實現。這里采用(yong)電阻網絡實現分(fen)流(liu)放電支路電阻較為合理(li)，可以(yi)有效(xiao)消除電阻偏差的影響，此外，還能起到降(jiang)低熱功耗的作用(yong)。