電動車充電器(qi)的有關知(zhi)識

 

 

充電器的分類：用有、無工頻（

50

赫茲）變壓器(qi)區分，可(ke)分為兩大類(lei)。貨運三輪充電(dian)器(qi)一

般(ban)使用帶工頻變壓器(qi)的充電(dian)機(ji)，體(ti)積大(da)、重量大(da)，費(fei)電(dian)，但是可靠，便(bian)宜；電(dian)動(dong)自行(xing)車和電(dian)

摩則使用所謂開關電源式充電器，省電，效率高(gao)，但是易壞(huai)。

 

 

 

 

 

開關電源(yuan)式充電器的正確操作是(shi)：

充電時，

先插電池，

后加市電；

充足后，

先切斷市電，

后(hou)拔(ba)電(dian)池插頭。如果在充(chong)電(dian)時(shi)先拔(ba)電(dian)池插頭，特別是充(chong)電(dian)電(dian)流大（紅燈）時(shi)，非常容易(yi)損壞

充電器。

 

 

 

 

 

 

 

常用的(de)開關電源式(shi)充(chong)電器又分半(ban)橋式(shi)和(he)單激式(shi)兩大類，

單激類又分(fen)為正激式和反激式

兩類。半(ban)橋(qiao)式(shi)成本(ben)高，性能好，常用于帶負脈沖的充電(dian)器；單(dan)激(ji)式(shi)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，

開始(shi)全球普(pu)遍沿(yan)引老的觀點和操(cao)作(zuo)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(sheng)為解(jie)決快(kuai)速充電問題，

1967

年向全世

界公布了他的研(yan)究成果，用大于

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(fang)電(dian)(dian)(dian)。放(fang)電(dian)(dian)(dian)有(you)利于

消(xiao)除極化、降(jiang)低電解(jie)液溫度、提高極板接受電荷的能力。

 

 

 

 

 

 

 

我(wo)國一些科技工作者在

1969

年前后(hou)，根據麥斯先(xian)生的(de)(de)三(san)定律制作成功了多種(zhong)品牌的(de)(de)

快速充電機。

充電循環過程是：

大(da)電(dian)(dian)流脈沖充電(dian)(dian)→切斷充電(dian)(dian)通路→對電(dian)(dian)池短暫放電(dian)(dian)→停止放

電→接通充(chong)電通路(lu)→大(da)電流脈沖充(chong)電??

 

 

 

 

 

 

 

 

2000

年前后，有人將這一原理用到了電動車充電器(qi)中，充電過(guo)程中，不(bu)切斷充電通

路(lu)，用小電阻(zu)將(jiang)電池短路(lu)瞬間，

進行放電(dian)(dian)。短路時由于(yu)不切斷充(chong)電(dian)(dian)通路，在充(chong)電(dian)(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）

，由于電感里的電流不(bu)能(neng)跳變，

短

路時間短促，

可以保(bao)護(hu)充電器的電源轉換部分(fen)。

如(ru)果(guo)把(ba)充電(dian)電(dian)流(liu)方向叫正，

放電自然為負了，

電動車業就出現(xian)了名詞“負(fu)脈(mo)沖充電器”

，而且稱(cheng)可以延長電池壽命等等。

 

 

 

 

 

 

 

關于三段式充電器

 

 

 

 

 

 

 

近幾年，

電動車普遍使(shi)用了所謂三段式充電器(qi)，

第(di)一(yi)個階段(duan)叫恒(heng)流階段(duan)，

第二個階段

叫恒壓階段，

第三個階段(duan)叫(jiao)涓流階段(duan)。

從電(dian)子技(ji)術角度針(zhen)對電(dian)池而言(yan)：

第一個階段叫充電限

流階段，

第二個階段叫高恒壓階段，

第三個(ge)階段叫低恒壓階段比較貼(tie)切。

第二階段和第三階

段轉換時，面板指示燈相應變換，大多數充電器第一、二階段是紅燈，第三(san)階段變綠燈。第

二階(jie)段(duan)和第(di)三(san)階(jie)段(duan)的(de)相互轉換(huan)是由(you)充電電流決(jue)定的(de)，

大于某(mou)電流進入第一(yi)第二階段，

小于某

電流進入第三階段。這個(ge)電流叫轉(zhuan)換電流，也叫轉(zhuan)折電流。

 

 

 

 

 

 

 

早期充電器，

包括名牌車(che)配套的充(chong)電器(qi)，雖然(ran)也變燈，

但實際是恒壓限流充電器，并

不是三階段充電(dian)(dian)器。一般這類就一個穩定電(dian)(dian)壓值，

44.2V

左右，對當(dang)時(shi)的高比重硫酸的電池

還湊合。

 

 

 

 

 

 

 

關于三段式充電器的三個(ge)關鍵參數(shu)

 

 

 

 

 

 

 

第一個重要(yao)參數是涓(juan)流階段的低恒壓值，

第二個(ge)重要參(can)數是第二階段的(de)高(gao)恒壓值，

第

三(san)(san)個重(zhong)要參(can)數(shu)(shu)是(shi)轉換(huan)電(dian)(dian)流(liu)。這三(san)(san)個重(zhong)要參(can)數(shu)(shu)與(yu)電(dian)(dian)池數(shu)(shu)目有關，與(yu)電(dian)(dian)池的(de)容量

Ah

有關，與溫

度有關(guan)，與電(dian)池種類(lei)有關(guan)。為了方(fang)便大(da)家記憶，下面(mian)以(yi)最常見的(de)電(dian)動自行(xing)車（三塊

12V

串

聯的

10Ah

電(dian)池）所(suo)用的三(san)段式充電(dian)器為例(li)簡單介(jie)紹一下：

 

 

 

 

 

 

 

 

首先(xian)討論涓流階段的低(di)恒壓(ya)值，

參考電壓為

42.5V

左右。

此值高將使電池(chi)失水，

容易

使電池發(fa)熱變形；此(ci)值低(di)(di)不利于電池充足電。此(ci)值在南(nan)方要低(di)(di)于

41.5V

；膠體電池要低于

41.5V

，如在南(nan)方還要低(di)一點兒。這(zhe)個(ge)參數(shu)是(shi)相(xiang)對嚴格(ge)的，不可(ke)以(yi)大(da)于參考值(zhi)。

 

 

 

 

 

 

 

其次討論第(di)二(er)階段(duan)的(de)高恒壓值，參(can)考電壓為

44.5V

左(zuo)右(you)。此值高有利于快速(su)充足電，

但(dan)是容(rong)易使電池失水，

充電(dian)后期電(dian)流下不來，

結果使電池發熱變形；

此值低不利于電(dian)池(chi)快(kuai)速(su)

充足電，有利于向涓流階段(duan)轉(zhuan)換。這個值(zhi)雖然沒有第一個值(zhi)那樣(yang)嚴格(ge)，但(dan)是也不要過高(gao)。

 

 

 

 

 

 

 

最后討論轉換電流，

參考電流為

300

毫安左右。

此值高有利于電池壽命，

不容易發熱

本文介紹的(de)是有關鋰(li)電池組(zu)保護(hu)板均(jun)衡充電基本工作原理，在采用單節(jie)鋰(li)電池保護(hu)芯片設計的(de)且(qie)具備均(jun)衡充電能力(li)的(de)鋰(li)電池組(zu)保護(hu)板，示(shi)意圖如圖1所示(shi)。

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)(dian)池(chi)數目確定，串聯使用，分別對所對應單節鋰電(dian)(dian)池(chi)的(de)充放電(dian)(dian)、過(guo)流、短路狀態進行保(bao)護(hu)。該系(xi)統(tong)在(zai)(zai)充電(dian)(dian)保(bao)護(hu)的(de)同時，通過(guo)保(bao)護(hu)芯片控制分流放電(dian)(dian)支路開關器(qi)件的(de)通斷實(shi)現均衡充電(dian)(dian)，該方案有別于傳(chuan)統(tong)的(de)在(zai)(zai)充電(dian)(dian)器(qi)端實(shi)現均衡充電(dian)(dian)的(de)做法，降低了鋰電(dian)(dian)池(chi)組(zu)充電(dian)(dian)器(qi)設(she)計應用的(de)成本。

圖1 具備均(jun)衡(heng)充(chong)電能力的鋰電池組保護(hu)板(ban)示意圖

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兩端的分(fen)流(liu)放電(dian)支路放電(dian)，同時將(jiang)串接在充(chong)電(dian)回路中的對應單體鋰電(dian)池斷離出充(chong)電(dian)回路。

鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組串(chuan)聯充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)，忽略(lve)單(dan)(dan)(dan)節(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)容量(liang)差(cha)別的(de)(de)影響，一般內阻較小(xiao)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)先(xian)(xian)(xian)充(chong)滿。此時(shi)(shi)，相(xiang)(xiang)應的(de)(de)過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)(bao)護信號(hao)控制(zhi)分(fen)(fen)流(liu)(liu)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)支(zhi)路(lu)的(de)(de)開關器(qi)(qi)件(jian)閉合，在(zai)原電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)兩(liang)端并聯上(shang)一個分(fen)(fen)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻。根據電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)PNGV等效(xiao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)模型，此時(shi)(shi)分(fen)(fen)流(liu)(liu)支(zhi)路(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻相(xiang)(xiang)當于先(xian)(xian)(xian)充(chong)滿的(de)(de)單(dan)(dan)(dan)節(jie)(jie)鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)負載(zai)，該電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)通(tong)過(guo)其(qi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)端電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)維(wei)持在(zai)充(chong)滿狀態(tai)(tai)附近一個極(ji)小(xiao)的(de)(de)范圍內。假設(she)第1節(jie)(jie)鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)先(xian)(xian)(xian)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)完成，進入(ru)過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)(bao)護狀態(tai)(tai)，則(ze)主(zhu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)及分(fen)(fen)流(liu)(liu)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)支(zhi)路(lu)中(zhong)(zhong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)流(liu)(liu)向(xiang)如(ru)圖(tu)3所示。當所有單(dan)(dan)(dan)節(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)均充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)進入(ru)過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)保(bao)(bao)護狀態(tai)(tai)時(shi)(shi)，全部單(dan)(dan)(dan)節(jie)(jie)鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)大(da)小(xiao)在(zai)誤差(cha)范圍內完全相(xiang)(xiang)等，各節(jie)(jie)保(bao)(bao)護芯片(pian)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)保(bao)(bao)護控制(zhi)信號(hao)均變低，無法為(wei)主(zhu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)中(zhong)(zhong)的(de)(de)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)控制(zhi)開關器(qi)(qi)件(jian)提供柵(zha)極(ji)偏壓(ya)，使其(qi)關斷，主(zhu)回路(lu)斷開，即(ji)實現均衡(heng)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)過(guo)程(cheng)完成。

圖3 分流均衡過程

當電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)時(shi)，外接負載分別接電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)正(zheng)負極(ji)BAT+和BAT-兩端(duan)，放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)流(liu)(liu)經電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)負極(ji)BAT-、充(chong)電(dian)(dian)(dian)(dian)控(kong)制開(kai)(kai)關(guan)器(qi)(qi)件(jian)(jian)、放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)控(kong)制開(kai)(kai)關(guan)器(qi)(qi)件(jian)(jian)、電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)中單(dan)(dan)(dan)節(jie)鋰電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)N～1和電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)正(zheng)極(ji)BAT+,電(dian)(dian)(dian)(dian)流(liu)(liu)流(liu)(liu)向(xiang)如(ru)圖(tu)4所(suo)示。系統中控(kong)制電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)部分單(dan)(dan)(dan)節(jie)鋰電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)保(bao)護芯片的(de)放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)欠電(dian)(dian)(dian)(dian)壓保(bao)護、過(guo)(guo)流(liu)(liu)和短路(lu)(lu)(lu)保(bao)護控(kong)制信號經光耦隔離后串聯(lian)輸出，為(wei)主電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)開(kai)(kai)關(guan)器(qi)(qi)件(jian)(jian)的(de)導通提供柵極(ji)電(dian)(dian)(dian)(dian)壓;一旦電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)在放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)過(guo)(guo)程中遇到單(dan)(dan)(dan)節(jie)鋰電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)欠電(dian)(dian)(dian)(dian)壓或者過(guo)(guo)流(liu)(liu)和短路(lu)(lu)(lu)等(deng)特(te)殊情況，對應的(de)單(dan)(dan)(dan)節(jie)鋰電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)保(bao)護控(kong)制信號變(bian)低，無法(fa)為(wei)主電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中的(de)放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)控(kong)制開(kai)(kai)關(guan)器(qi)(qi)件(jian)(jian)提供柵極(ji)偏(pian)壓，使其關(guan)斷，主回(hui)路(lu)(lu)(lu)斷開(kai)(kai)，即結(jie)束放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)使用過(guo)(guo)程。

圖4 放電過程

一般鋰電(dian)(dian)(dian)(dian)(dian)池采(cai)用恒流-恒壓(TAPER)型充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)控制，恒壓充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)時(shi)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流近似指數規(gui)律(lv)減小。系統中充(chong)(chong)放電(dian)(dian)(dian)(dian)(dian)主回(hui)路(lu)的開(kai)關器件可根據外部電(dian)(dian)(dian)(dian)(dian)路(lu)要求(qiu)滿足的最大工作電(dian)(dian)(dian)(dian)(dian)流和工作電(dian)(dian)(dian)(dian)(dian)壓選型。

控制電(dian)路(lu)的單節鋰電(dian)池保護芯片可(ke)根據待(dai)保護的單節鋰電(dian)池的電(dian)壓(ya)等級、保護延遲時(shi)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充電(dian)(dian)(dian)電(dian)(dian)(dian)壓大(da)(da)小以及鋰(li)(li)電(dian)(dian)(dian)池(chi)的參數和放電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)的大(da)(da)小計(ji)算得出。均衡電(dian)(dian)(dian)流(liu)應合理(li)選擇，如(ru)(ru)果(guo)(guo)(guo)太小，均衡效果(guo)(guo)(guo)不明顯；如(ru)(ru)果(guo)(guo)(guo)太大(da)(da)，系(xi)統的能量損耗大(da)(da)，均衡效率(lv)低，對鋰(li)(li)電(dian)(dian)(dian)池(chi)組熱管理(li)要求高，一般電(dian)(dian)(dian)流(liu)大(da)(da)小可設計(ji)在50～100mA之(zhi)間。

分流放電(dian)(dian)(dian)支路(lu)(lu)電(dian)(dian)(dian)阻可采用功(gong)率電(dian)(dian)(dian)阻或(huo)電(dian)(dian)(dian)阻網絡(luo)實(shi)(shi)現。這里采用電(dian)(dian)(dian)阻網絡(luo)實(shi)(shi)現分流放電(dian)(dian)(dian)支路(lu)(lu)電(dian)(dian)(dian)阻較為合理，可以(yi)有效消除電(dian)(dian)(dian)阻偏差的影(ying)響，此外，還能起到(dao)降低熱功(gong)耗的作用。