電(dian)(dian)動車充電(dian)(dian)器的有關知識

 

 

充電器的(de)分(fen)類：用有、無工頻（

50

赫茲）變壓器(qi)區(qu)分(fen)，可分(fen)為兩大類。貨運(yun)三(san)輪充電器(qi)一

般使(shi)用(yong)帶工(gong)頻變壓(ya)器的(de)充電(dian)機，體(ti)積大(da)、重量大(da)，費電(dian)，但是可靠(kao)，便宜(yi)；電(dian)動自行車和電(dian)

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

 

 

 

 

 

開關電源(yuan)式(shi)充電器的正確操作(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(chi)插頭。如果在充電(dian)時先拔電(dian)池(chi)插頭，特別是充電(dian)電(dian)流大（紅燈）時，非常(chang)容易損壞

充電器。

 

 

 

 

 

 

 

常(chang)用的開關(guan)電源式(shi)充電器又分半橋式(shi)和單激式(shi)兩大(da)類，

單(dan)激類又分為正(zheng)激式和反激式

兩類。半橋式成本(ben)(ben)高，性能好(hao)，常(chang)用于帶負脈沖的充(chong)電器；單激式成本(ben)(ben)低，市(shi)場(chang)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，

開始全球普遍(bian)沿(yan)引老的觀點和操(cao)作規(gui)程：

充、

放

電率為

0.1C(C

是電池容量

)

壽命較長。

美國人麥斯先生為解決快速充電問題，

1967

年向全世

界(jie)公布了他的研究成果，用(yong)大于(yu)

1C

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

消(xiao)除極化(hua)、降低電解液溫度、提高(gao)極板接受(shou)電荷(he)的能力。

 

 

 

 

 

 

 

我國(guo)一(yi)些科技工(gong)作(zuo)者在

1969

年前后，根據麥斯先生(sheng)的三定律(lv)制作(zuo)成功了多種(zhong)品牌的

快速充電機。

充電循環過程是：

大電(dian)(dian)(dian)流脈(mo)沖(chong)充(chong)電(dian)(dian)(dian)→切斷充(chong)電(dian)(dian)(dian)通路→對電(dian)(dian)(dian)池短暫放(fang)電(dian)(dian)(dian)→停止(zhi)放(fang)

電(dian)→接通充電(dian)通路→大電(dian)流脈沖充電(dian)??

 

 

 

 

 

 

 

 

2000

年前后(hou)，有(you)人將這(zhe)一(yi)原理用(yong)到(dao)了(le)電動車充(chong)電器中(zhong)，充(chong)電過程中(zhong)，不切(qie)斷充(chong)電通

路，用小(xiao)電阻將電池短路瞬間，

進行放電(dian)。短路(lu)時由于(yu)不切(qie)斷(duan)充電(dian)通(tong)(tong)路(lu)，在充電(dian)通(tong)(tong)路(lu)中串(chuan)連(lian)

了電感。一般在

1

秒內短路

3

－

5

毫秒（

1

秒＝

1000

毫秒）

，由(you)于電(dian)感里的電(dian)流不能跳變，

短

路時間短促，

可以保(bao)護充(chong)電器的電源轉換部分。

如果把充電(dian)電(dian)流方向(xiang)叫正，

放電自然為負了，

電動車業就出現了(le)名詞“負脈沖充電器”

，而且稱可(ke)以延長電池壽命等等。

 

 

 

 

 

 

 

關于三段式充電器

 

 

 

 

 

 

 

近幾年，

電(dian)(dian)動車普遍使用了所(suo)謂(wei)三段式充電(dian)(dian)器，

第(di)一個階段叫恒流階段，

第二個階段

叫恒壓階段，

第三(san)個階(jie)段叫涓流階(jie)段。

從電子技術角度針(zhen)對電池而言：

第一個階段叫充電限

流階段，

第(di)二個階段(duan)叫高恒壓階段(duan)，

第三個階段(duan)叫低(di)恒壓階段(duan)比較貼切。

第二階段和第三階

段轉換時(shi)，面板指示燈相應變換，大(da)多數充電器(qi)第(di)一、二階段是(shi)紅燈，第(di)三階段變綠燈。第(di)

二階段和第三階段的相互(hu)轉換(huan)是由充電(dian)電(dian)流決定的，

大于某(mou)電流進入第一第二階段，

小于某

電流(liu)(liu)進入第(di)三階段。這(zhe)個(ge)電流(liu)(liu)叫(jiao)轉(zhuan)換電流(liu)(liu)，也(ye)叫(jiao)轉(zhuan)折電流(liu)(liu)。

 

 

 

 

 

 

 

早期充電器，

包括名牌(pai)車配套的充電器，雖然也變(bian)燈，

但實際是恒壓限流(liu)充電器(qi)，并

不(bu)是三階段(duan)充電器。一般這類(lei)就一個穩(wen)定電壓值，

44.2V

左右，對當時的高(gao)比重硫(liu)酸的電(dian)池(chi)

還湊合。

 

 

 

 

 

 

 

關于三段式充(chong)電(dian)器的三個關鍵參數

 

 

 

 

 

 

 

第一個重要參數是涓流階段(duan)的低恒壓(ya)值(zhi)，

第二(er)個重要參數是第二(er)階段(duan)的高恒(heng)壓值，

第

三(san)個(ge)重(zhong)要(yao)(yao)參數是(shi)轉換電流。這三(san)個(ge)重(zhong)要(yao)(yao)參數與(yu)電池(chi)數目有關，與(yu)電池(chi)的容量

Ah

有關，與溫

度有關，與電池(chi)種類有關。為了(le)方(fang)便大家記憶，下(xia)面以最常見的電動自行車（三(san)塊(kuai)

12V

串

聯的

10Ah

電池）所用的三段(duan)式充電器為例簡(jian)單(dan)介紹(shao)一下：

 

 

 

 

 

 

 

 

首先討論涓流階段的低恒壓值，

參考電壓為

42.5V

左右。

此值高將使電(dian)池失水，

容易

使(shi)電池發熱變形；此值(zhi)低(di)不(bu)利(li)于電池充(chong)足電。此值(zhi)在南(nan)方要低(di)于

41.5V

；膠體電池要低于

41.5V

，如(ru)在南方還(huan)要低一點(dian)兒。這個參數是相(xiang)對嚴格的，不可以大于參考(kao)值。

 

 

 

 

 

 

 

其次討論第二階段(duan)的高(gao)恒壓值(zhi)，參考電壓為

44.5V

左右。此值高有利于快(kuai)速充(chong)足電，

但是容(rong)易使(shi)電(dian)池失水，

充(chong)電(dian)后(hou)期電(dian)流下不(bu)來，

結果使電池發熱變形；

此值低不利于電池快速(su)

充足電，有利于向(xiang)涓流階段(duan)轉換。這(zhe)個值雖然沒有第一個值那樣嚴格，但(dan)是也不要過高。

 

 

 

 

 

 

 

最后討論轉換電流，

參考電流為

300

毫安左右。

此值高(gao)有(you)利于電池壽命，

不容易發熱

本(ben)文介紹的是有(you)關鋰電(dian)池(chi)組保護(hu)(hu)板(ban)均衡(heng)充電(dian)基本(ben)工作原理(li)，在采用單(dan)節鋰電(dian)池(chi)保護(hu)(hu)芯片設計的且具備(bei)均衡(heng)充電(dian)能(neng)力的鋰電(dian)池(chi)組保護(hu)(hu)板(ban)，示意(yi)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池數目(mu)確定，串聯使用，分別對(dui)所對(dui)應單節鋰電池的(de)充(chong)(chong)放(fang)電、過流、短路(lu)狀態(tai)進行(xing)保護(hu)。該系統在(zai)(zai)充(chong)(chong)電保護(hu)的(de)同時(shi)，通過保護(hu)芯片控制分流放(fang)電支路(lu)開關(guan)器(qi)件(jian)的(de)通斷實現均衡充(chong)(chong)電，該方案有別于傳統的(de)在(zai)(zai)充(chong)(chong)電器(qi)端實現均衡充(chong)(chong)電的(de)做(zuo)法，降低了鋰電池組(zu)充(chong)(chong)電器(qi)設(she)計應用的(de)成本。

圖(tu)1 具備(bei)均(jun)衡充電能力的鋰電池組保護板示意圖(tu)

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兩(liang)端的分流(liu)放電(dian)(dian)(dian)支路(lu)(lu)放電(dian)(dian)(dian)，同時將串接(jie)在充(chong)電(dian)(dian)(dian)回(hui)路(lu)(lu)中的對應單體鋰電(dian)(dian)(dian)池(chi)斷離出充(chong)電(dian)(dian)(dian)回(hui)路(lu)(lu)。

鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)池組串(chuan)聯(lian)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)時，忽(hu)略單節(jie)(jie)電(dian)(dian)(dian)(dian)(dian)池容量差別的(de)(de)(de)(de)影(ying)響，一般內阻較(jiao)小(xiao)(xiao)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)池先充(chong)(chong)滿。此(ci)時，相(xiang)應的(de)(de)(de)(de)過(guo)電(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)(bao)護信(xin)號(hao)控(kong)制分(fen)流放電(dian)(dian)(dian)(dian)(dian)支(zhi)路(lu)(lu)的(de)(de)(de)(de)開關(guan)器(qi)件閉合，在(zai)原(yuan)電(dian)(dian)(dian)(dian)(dian)池兩端并聯(lian)上一個分(fen)流電(dian)(dian)(dian)(dian)(dian)阻。根據電(dian)(dian)(dian)(dian)(dian)池的(de)(de)(de)(de)PNGV等(deng)效電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)模型，此(ci)時分(fen)流支(zhi)路(lu)(lu)電(dian)(dian)(dian)(dian)(dian)阻相(xiang)當(dang)于先充(chong)(chong)滿的(de)(de)(de)(de)單節(jie)(jie)鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)池的(de)(de)(de)(de)負(fu)載，該(gai)電(dian)(dian)(dian)(dian)(dian)池通過(guo)其(qi)放電(dian)(dian)(dian)(dian)(dian)，使(shi)電(dian)(dian)(dian)(dian)(dian)池端電(dian)(dian)(dian)(dian)(dian)壓(ya)維持在(zai)充(chong)(chong)滿狀(zhuang)(zhuang)態附近一個極小(xiao)(xiao)的(de)(de)(de)(de)范圍(wei)內。假設(she)第1節(jie)(jie)鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)池先充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)完成，進(jin)入(ru)過(guo)電(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)(bao)護狀(zhuang)(zhuang)態，則主(zhu)(zhu)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)及分(fen)流放電(dian)(dian)(dian)(dian)(dian)支(zhi)路(lu)(lu)中電(dian)(dian)(dian)(dian)(dian)流流向如(ru)圖3所示。當(dang)所有單節(jie)(jie)電(dian)(dian)(dian)(dian)(dian)池均充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)進(jin)入(ru)過(guo)電(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)(bao)護狀(zhuang)(zhuang)態時，全部單節(jie)(jie)鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓(ya)大小(xiao)(xiao)在(zai)誤差范圍(wei)內完全相(xiang)等(deng)，各節(jie)(jie)保(bao)(bao)護芯片充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)保(bao)(bao)護控(kong)制信(xin)號(hao)均變低(di)，無法為(wei)主(zhu)(zhu)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中的(de)(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)控(kong)制開關(guan)器(qi)件提(ti)供(gong)柵極偏壓(ya)，使(shi)其(qi)關(guan)斷，主(zhu)(zhu)回路(lu)(lu)斷開，即(ji)實現均衡充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)過(guo)程完成。

圖3 分流均衡過程

當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時，外接負載分(fen)別接電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)正負極(ji)BAT+和BAT-兩端(duan)，放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流流經(jing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)負極(ji)BAT-、充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制(zhi)(zhi)開(kai)關(guan)(guan)器(qi)件(jian)、放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制(zhi)(zhi)開(kai)關(guan)(guan)器(qi)件(jian)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)中(zhong)單節(jie)鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)N～1和電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)正極(ji)BAT+,電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流流向如圖4所示。系(xi)統中(zhong)控(kong)(kong)制(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)部分(fen)單節(jie)鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)保(bao)護(hu)(hu)芯片(pian)的放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)欠(qian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)護(hu)(hu)、過流和短路(lu)(lu)保(bao)護(hu)(hu)控(kong)(kong)制(zhi)(zhi)信號經(jing)光耦(ou)隔(ge)離后(hou)串聯輸出，為主電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中(zhong)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)開(kai)關(guan)(guan)器(qi)件(jian)的導通(tong)提供柵極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya);一旦電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)在放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)過程中(zhong)遇到(dao)單節(jie)鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)欠(qian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)或(huo)者(zhe)過流和短路(lu)(lu)等特(te)殊情況，對應的單節(jie)鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)保(bao)護(hu)(hu)控(kong)(kong)制(zhi)(zhi)信號變低，無(wu)法為主電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中(zhong)的放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制(zhi)(zhi)開(kai)關(guan)(guan)器(qi)件(jian)提供柵極(ji)偏壓(ya)，使其關(guan)(guan)斷(duan)，主回路(lu)(lu)斷(duan)開(kai)，即結束放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)使用過程。

圖4 放電過程

一般鋰電(dian)(dian)池(chi)采(cai)用恒(heng)流-恒(heng)壓(ya)(TAPER)型充(chong)電(dian)(dian)控制，恒(heng)壓(ya)充(chong)電(dian)(dian)時，充(chong)電(dian)(dian)電(dian)(dian)流近似指數規律減小。系(xi)統中充(chong)放(fang)電(dian)(dian)主回路(lu)的開關器件可根據外部電(dian)(dian)路(lu)要(yao)求滿(man)足的最大工作電(dian)(dian)流和工作電(dian)(dian)壓(ya)選型。

控制電(dian)路的單節鋰電(dian)池(chi)保(bao)(bao)(bao)護芯片可(ke)根據待保(bao)(bao)(bao)護的單節鋰電(dian)池(chi)的電(dian)壓等級、保(bao)(bao)(bao)護延遲時間等選型。

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)(de)充電(dian)電(dian)壓大小以及鋰(li)電(dian)池(chi)的(de)(de)參數和放電(dian)電(dian)流(liu)的(de)(de)大小計算(suan)得(de)出。均衡電(dian)流(liu)應合理選擇，如果(guo)太(tai)小，均衡效果(guo)不明顯(xian)；如果(guo)太(tai)大，系(xi)統的(de)(de)能(neng)量損耗大，均衡效率低，對(dui)鋰(li)電(dian)池(chi)組熱管理要求高(gao)，一般電(dian)流(liu)大小可設(she)計在50～100mA之間(jian)。

分(fen)流(liu)放(fang)電(dian)(dian)(dian)支(zhi)路電(dian)(dian)(dian)阻可采用(yong)功率電(dian)(dian)(dian)阻或電(dian)(dian)(dian)阻網絡(luo)實(shi)現(xian)。這里采用(yong)電(dian)(dian)(dian)阻網絡(luo)實(shi)現(xian)分(fen)流(liu)放(fang)電(dian)(dian)(dian)支(zhi)路電(dian)(dian)(dian)阻較為合理，可以有效消除(chu)電(dian)(dian)(dian)阻偏差(cha)的影響，此(ci)外，還(huan)能起到降低熱功耗(hao)的作用(yong)。