對于接受到新的基于電池的(de)(de)電源系統(tong)設(she)(she)計(ji)監視器電路(lu)，要采取什么策略來優化該設(she)(she)計(ji)才能在(zai)控制成本(ben)的(de)(de)情況下實(shi)現建立一個高效電池管理系統(tong)呢?最初(chu)考慮(lv)的(de)(de)問題(ti)將是確定系統(tong)的(de)(de)結(jie)構(gou)(gou)以及電池和有關電子組件的(de)(de)位置(zhi)。基本(ben)結(jie)構(gou)(gou)清楚以后(hou)，接(jie)下來必須考慮(lv)的(de)(de)一個問題(ti)是，電路(lu)拓撲的(de)(de)權衡協(xie)調問題(ti)，例如，怎(zen)樣優化最終產品的(de)(de)通信和互連(lian)。

電池(chi)(chi)(chi)(chi)的(de)(de)外形(xing)尺(chi)寸將對電源(yuan)系統結構有重大影響。要(yao)使用大量單體電池(chi)(chi)(chi)(chi)組(zu)成電池(chi)(chi)(chi)(chi)模(mo)塊 (或(huo)電池(chi)(chi)(chi)(chi)組(zu)) ，或(huo)者要(yao)使用外形(xing)尺(chi)寸很大的(de)(de)電池(chi)(chi)(chi)(chi)，因而(er)由于(yu)重量問題而(er)導致(zhi)對電池(chi)(chi)(chi)(chi)數量的(de)(de)限制(zhi)或(huo)引起(qi)其他的(de)(de)尺(chi)寸限制(zhi)?這也(ye)(ye)許是設計變數最(zui)大的(de)(de)部分，因為外形(xing)新穎的(de)(de)電池(chi)(chi)(chi)(chi)不斷(duan)上市(shi)，而(er)且(qie)人們(men)也(ye)(ye)在(zai)不斷(duan)努力，務求電池(chi)(chi)(chi)(chi)模(mo)塊或(huo)電池(chi)(chi)(chi)(chi)組(zu)集(ji)成到產品(pin)中后，會與整個產品(pin)概念更加(jia)一致(zhi)。

另(ling)一(yi)個考慮因素是，電(dian)(dian)池(chi)(chi) (或(huo)(huo)模塊化電(dian)(dian)池(chi)(chi)組(zu))、電(dian)(dian)池(chi)(chi)管理(li)(li)系統 (或(huo)(huo)其子系統) 以(yi)及最(zui)(zui)終應用接口(kou)之間(jian)的測試信(xin)號(hao)和/或(huo)(huo)遙測信(xin)號(hao)的互連(lian)。在大(da)多數(shu)情況下，可以(yi)做(zuo)一(yi)個外殼，用來集成電(dian)(dian)池(chi)(chi)模塊或(huo)(huo)電(dian)(dian)池(chi)(chi)組(zu)中(zhong)(zhong)的某(mou)些數(shu)據采集電(dian)(dian)路，以(yi)便如果需(xu)要調換(huan)，那么(me)生產 ID、校準、使用規格(ge)等重(zhong)要信(xin)息能(neng)隨(sui)著可替換(huan)組(zu)件帶走。這類信(xin)息對電(dian)(dian)池(chi)(chi)管理(li)(li)系統 (BMS)或(huo)(huo)維修設備(bei)可能(neng)有用，而且最(zui)(zui)大(da)限度地減少了線束中(zhong)(zhong)所需(xu)的高(gao)壓額定值(zhi)導線的數(shu)量。

接(jie)下(xia)來(lai)，就給定(ding)(ding)的(de)(de)(de)機械概(gai)念設計而(er)(er)言，監視硬件拓撲(pu)(pu)由精確定(ding)(ding)義的(de)(de)(de)、所(suo)(suo)需(xu)(xu)支(zhi)持的(de)(de)(de)電(dian)(dian)(dian)池(chi)(chi)(chi)數(shu)(shu)量(liang)(liang)決(jue)(jue)定(ding)(ding)。在(zai)(zai)(zai)(zai)(zai)汽車應(ying)用(yong)(yong)中，一(yi)(yi)般情(qing)況下(xia)總共會有(you) 100 個以(yi)上(shang)的(de)(de)(de)電(dian)(dian)(dian)池(chi)(chi)(chi)測(ce)量(liang)(liang)點，而(er)(er)且系(xi)統的(de)(de)(de)模塊(kuai)化將(jiang)決(jue)(jue)定(ding)(ding)一(yi)(yi)個給定(ding)(ding)的(de)(de)(de)電(dian)(dian)(dian)路(lu)系(xi)統測(ce)量(liang)(liang)多(duo)少個電(dian)(dian)(dian)池(chi)(chi)(chi)。最(zui)常見的(de)(de)(de)情(qing)況是(shi)(shi)，以(yi)安全(quan)斷接(jie)“維修插頭(tou)”方式，將(jiang)所(suo)(suo)有(you)電(dian)(dian)(dian)池(chi)(chi)(chi)分(fen)(fen)(fen)成至少兩個子組。通過在(zai)(zai)(zai)(zai)(zai)故障(zhang)情(qing)況下(xia)保持電(dian)(dian)(dian)壓低于 200V，這(zhe)(zhe)種(zhong)方法(fa)最(zui)大限度地(di)降(jiang)低了(le)維修人員可能(neng)(neng)遇到的(de)(de)(de)觸電(dian)(dian)(dian)危險。外形尺(chi)寸較大的(de)(de)(de)電(dian)(dian)(dian)池(chi)(chi)(chi)組意味著(zhu)，要(yao)采(cai)用(yong)(yong)兩套隔離的(de)(de)(de)數(shu)(shu)據(ju)采(cai)集(ji)系(xi)統，每套也(ye)許支(zhi)持 50 個電(dian)(dian)(dian)池(chi)(chi)(chi)分(fen)(fen)(fen)接(jie)頭(tou)。在(zai)(zai)(zai)(zai)(zai)有(you)些情(qing)況下(xia)，所(suo)(suo)有(you)電(dian)(dian)(dian)子組件都(dou)在(zai)(zai)(zai)(zai)(zai)一(yi)(yi)個經濟實(shi)惠的(de)(de)(de)印刷(shua)電(dian)(dian)(dian)路(lu)板上(shang)，但(dan)是(shi)(shi)這(zhe)(zhe)需(xu)(xu)要(yao)大量(liang)(liang)互連(lian)，如(ru)圖(tu) 1 (a)所(suo)(suo)示。或者，電(dian)(dian)(dian)子組件也(ye)可以(yi)分(fen)(fen)(fen)散放置(zhi)，更加緊(jin)密(mi)地(di)集(ji)成在(zai)(zai)(zai)(zai)(zai)電(dian)(dian)(dian)池(chi)(chi)(chi)模塊(kuai)中，但(dan)是(shi)(shi)這(zhe)(zhe)需(xu)(xu)要(yao)采(cai)用(yong)(yong)遙測(ce)鏈接(jie)方法(fa)。為了(le)實(shi)現可靠的(de)(de)(de)數(shu)(shu)據(ju)完整性，內置(zhi)于汽車線束中的(de)(de)(de)遠(yuan)端測(ce)量(liang)(liang)功能(neng)(neng)電(dian)(dian)(dian)路(lu)必(bi)須采(cai)用(yong)(yong)一(yi)(yi)種(zhong)堅固型協議，例如(ru)廣泛使用(yong)(yong)的(de)(de)(de) CAN 總線。盡管真(zhen)正的(de)(de)(de) CAN 總線接(jie)口涉及幾個網(wang)絡層，但(dan)是(shi)(shi)可以(yi)很方便地(di)采(cai)用(yong)(yong) PHY 層構成 BMS LAN 結構，以(yi)高效(xiao)率(lv)地(di)進行模塊(kuai)內的(de)(de)(de)通信(xin)。該拓撲(pu)(pu)允許在(zai)(zai)(zai)(zai)(zai)幾個小型處理(li)器之間分(fen)(fen)(fen)配計算工作量(liang)(liang)，從而(er)(er)降(jiang)低所(suo)(suo)需(xu)(xu)的(de)(de)(de)數(shu)(shu)據(ju)傳輸速率(lv)，并減(jian)輕 LAN 方法(fa)可能(neng)(neng)引起的(de)(de)(de) EMI 問題(ti)。最(zui)終(zhong)的(de)(de)(de) BMS 應(ying)用(yong)(yong)接(jie)口很可能(neng)(neng)是(shi)(shi)至一(yi)(yi)個主系(xi)統管理(li)處理(li)器的(de)(de)(de) CAN 總線接(jie)線，而(er)(er)且將(jiang)需(xu)(xu)要(yao)定(ding)(ding)義 (或在(zai)(zai)(zai)(zai)(zai)一(yi)(yi)開始規定(ding)(ding)) 特定(ding)(ding)的(de)(de)(de)信(xin)息(xi)事(shi)務處理(li)。

其他因素也(ye)可能對物(wu)理結構和(he)監(jian)視電(dian)(dian)(dian)路造成影響。就鋰(li)離子電(dian)(dian)(dian)池而(er)言，需要電(dian)(dian)(dian)池容量平(ping)衡(heng)，從而(er)導致了(le)額(e)(e)外(wai)的熱量管理問題(ti)(去除熱量)，而(er)且如果(guo)需要有(you)源(yuan)平(ping)衡(heng)，還(huan)需要電(dian)(dian)(dian)源(yuan)轉換電(dian)(dian)(dian)路。溫(wen)度探頭常常分(fen)布在(zai)整(zheng)個(ge)模(mo)塊之(zhi)(zhi)上(shang)，以提供一(yi)種將電(dian)(dian)(dian)壓(ya)讀數(shu)與充電(dian)(dian)(dian)狀態關(guan)聯起來的方(fang)法，因而(er)需要一(yi)些支(zhi)持(chi)電(dian)(dian)(dian)路和(he)連(lian)接方(fang)案。設計時一(yi)個(ge)常常忽視的考慮(lv)因素是(shi)，當(dang)產品安(an)裝之(zhi)(zhi)前閑置或儲存在(zai)貨架上(shang)時，電(dian)(dian)(dian)池的電(dian)(dian)(dian)量泄漏應該是(shi)最低的。在(zai)有(you)些情況下，額(e)(e)外(wai)的控制配(pei)線是(shi)必要的。

在上面(mian)實現的(de)(de)(de)這些結構(gou)中(zhong)，都有一(yi)(yi)(yi)(yi)個(ge)常見(jian)的(de)(de)(de)測量(liang)功能構(gou)件(jian)，該(gai)構(gou)件(jian)包括一(yi)(yi)(yi)(yi)個(ge)多(duo)通道(dao) ADC、安全隔(ge)離(li)勢壘和某種程度(du)的(de)(de)(de)本地(di)處(chu)理能力(li)。實現功能的(de)(de)(de)核(he)心組(zu)件(jian)是凌力(li)爾特的(de)(de)(de) LTC6803 電(dian)池(chi)(chi)(chi)組(zu)監視器(qi) IC，同(tong)(tong)時顯(xian)示的(de)(de)(de)還有一(yi)(yi)(yi)(yi)個(ge)SPI 數據隔(ge)離(li)器(qi)和一(yi)(yi)(yi)(yi)些可(ke)選的(de)(de)(de)特殊用途電(dian)路。該(gai)電(dian)路包括輸入濾波(bo)器(qi)和無源平衡功能，構(gou)成了一(yi)(yi)(yi)(yi)個(ge)完(wan)整的(de)(de)(de)12 節(jie)電(dian)池(chi)(chi)(chi)數據采集解決(jue)方案。如(ru)果(guo)需要，這類電(dian)路可(ke)以簡單地(di)復制(zhi)，以支持更多(duo)電(dian)池(chi)(chi)(chi)測量(liang)方案，同(tong)(tong)時共享主微控(kong)制(zhi)器(qi)的(de)(de)(de)本地(di) SPI 端口，該(gai)主微控(kong)制(zhi)器(qi)反過來再(zai)提供外(wai)部CAN總線或(huo)其他(ta)LAN型(xing)數據鏈路所需。

與(yu)前一(yi)(yi)(yi)(yi)代(dai)監視器(qi)件(jian)相比，LTC6803的主要(yao)改進是，支持(chi)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)停機和(he)/或(huo)單獨由電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)(zu)供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)。當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)從(cong)(cong)V+引腳去掉(diao)時，電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)加載(zai)將降至零(僅有(you)nA級半導體(ti)泄漏(lou))。工(gong)作電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)可(ke)(ke)以(yi)(yi)由接(jie)通的電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)(zu)電(dian)(dian)(dian)(dian)(dian)(dian)壓提(ti)供(gong)，或(huo)從(cong)(cong)一(yi)(yi)(yi)(yi)個(ge)(ge)單獨的電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)提(ti)供(gong)給V+，只要(yao)電(dian)(dian)(dian)(dian)(dian)(dian)壓始終(zhong)至少與(yu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)(zu)一(yi)(yi)(yi)(yi)樣高就行。為了實現簡單性，LTC6803 還(huan)可(ke)(ke)以(yi)(yi)直接(jie)從(cong)(cong)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)(zu)獲(huo)取功率(lv)，在(zai)這(zhe)種情況下，最低功率(lv)狀態(即備用) 將僅消耗(hao) 12uA 電(dian)(dian)(dian)(dian)(dian)(dian)流。LTM2883 數據隔離(li)(li)器(qi)通過一(yi)(yi)(yi)(yi)個(ge)(ge)內部隔離(li)(li)的 DC-DC轉換器(qi)，從(cong)(cong)主處(chu)理(li)器(qi)供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)，因此該器(qi)件(jian)將自動(dong)與(yu)主處(chu)理(li)器(qi)一(yi)(yi)(yi)(yi)起斷電(dian)(dian)(dian)(dian)(dian)(dian)。LTM2883的一(yi)(yi)(yi)(yi)個(ge)(ge)非(fei)常有(you)用的功能(neng)是，它還(huan)能(neng)向(xiang)隔離(li)(li)的電(dian)(dian)(dian)(dian)(dian)(dian)子組(zu)(zu)件(jian)(即電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)端) 提(ti)供(gong)很大和(he)得自主機的功率(lv)。一(yi)(yi)(yi)(yi)個(ge)(ge)小型升(sheng)壓電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)功能(neng)組(zu)(zu)件(jian)就是這(zhe)樣驅動(dong)的，以(yi)(yi)獨立地給 LTC6803 供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)，以(yi)(yi)便電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)僅提(ti)供(gong) ADC 測量(liang)輸入電(dian)(dian)(dian)(dian)(dian)(dian)流 (即在(zai)有(you)效轉換時平均值< 200nA)。該電(dian)(dian)(dian)(dian)(dian)(dian)路具(ju)有(you)絕(jue)對最低的寄生電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)泄漏(lou)，同時消除了任何電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的工(gong)作電(dian)(dian)(dian)(dian)(dian)(dian)流失(shi)配，否(fou)則這(zhe)種失(shi)配可(ke)(ke)能(neng)逐(zhu)步導致電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)容量(liang)失(shi)衡。

LTC6803 的(de)(de)(de)(de)(de)一個(ge)(ge)方(fang)便(bian)的(de)(de)(de)(de)(de)功(gong)能(neng)(neng)是(shi)(shi)(shi)，有(you)兩個(ge)(ge)自由的(de)(de)(de)(de)(de)、準(zhun)(zhun)確度(du)(du)(du)與(yu)電(dian)(dian)(dian)(dian)池(chi)輸(shu)入(ru)(ru)類(lei)似的(de)(de)(de)(de)(de) ADC 輸(shu)入(ru)(ru)。這(zhe)種(zhong)方(fang)便(bian)的(de)(de)(de)(de)(de)功(gong)能(neng)(neng)允許用(yong)(yong)(yong)很少的(de)(de)(de)(de)(de)額外(wai)電(dian)(dian)(dian)(dian)路(lu)進行輔助(zhu)測(ce)(ce)(ce)量，包括(kuo)溫度(du)(du)(du)、校準(zhun)(zhun)信(xin)號或負(fu)載電(dian)(dian)(dian)(dian)流(liu)測(ce)(ce)(ce)量。一種(zhong)尤其有(you)用(yong)(yong)(yong)的(de)(de)(de)(de)(de)測(ce)(ce)(ce)量是(shi)(shi)(shi)，用(yong)(yong)(yong)一個(ge)(ge)門(men)控(kong)(kong)電(dian)(dian)(dian)(dian)阻分壓(ya)器(qi)測(ce)(ce)(ce)量整個(ge)(ge)電(dian)(dian)(dian)(dian)池(chi)組(zu)的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)壓(ya)，實現(xian)(xian)方(fang)法如圖 2 所(suo)示(shi) (采用(yong)(yong)(yong) 12:1 的(de)(de)(de)(de)(de)比例(li)，連(lian)接到VTEMP1 輸(shu)入(ru)(ru))。當電(dian)(dian)(dian)(dian)路(lu)斷電(dian)(dian)(dian)(dian)時(shi)，相(xiang)關的(de)(de)(de)(de)(de) FET 斷開(kai)，這(zhe)樣對電(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)(de)(de)測(ce)(ce)(ce)量就不(bu)會(hui)不(bu)必(bi)要(yao)地(di)(di)加重(zhong)電(dian)(dian)(dian)(dian)池(chi)的(de)(de)(de)(de)(de)負(fu)擔。既然該端口的(de)(de)(de)(de)(de)濾波可以(yi)獨(du)立于(yu)電(dian)(dian)(dian)(dian)池(chi)輸(shu)入(ru)(ru)來定制，那(nei)么(me)為(wei)了實現(xian)(xian)精確的(de)(de)(de)(de)(de)充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)計算所(suo)需(xu)的(de)(de)(de)(de)(de)、真(zhen)正高達 200sps 的(de)(de)(de)(de)(de)奈(nai)奎斯特 (Nyquist)采樣率(lv)是(shi)(shi)(shi)可能(neng)(neng)的(de)(de)(de)(de)(de)。可以(yi)利用(yong)(yong)(yong)對單個(ge)(ge)電(dian)(dian)(dian)(dian)池(chi)測(ce)(ce)(ce)量來周期性地(di)(di)對整個(ge)(ge)電(dian)(dian)(dian)(dian)池(chi)組(zu)的(de)(de)(de)(de)(de)分壓(ya)器(qi)提供軟件校準(zhun)(zhun)，這(zhe)樣就不(bu)需(xu)要(yao)價格昂貴的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)阻器(qi)了。輔助(zhu)輸(shu)入(ru)(ru)的(de)(de)(de)(de)(de)另一個(ge)(ge)非常(chang)有(you)用(yong)(yong)(yong)的(de)(de)(de)(de)(de)用(yong)(yong)(yong)法是(shi)(shi)(shi)，測(ce)(ce)(ce)量準(zhun)(zhun)確度(du)(du)(du)很高的(de)(de)(de)(de)(de)校準(zhun)(zhun)電(dian)(dian)(dian)(dian)源(諸如凌(ling)力爾特的(de)(de)(de)(de)(de) LT6655-3.3，一個(ge)(ge)準(zhun)(zhun)確度(du)(du)(du)為(wei) 0.025% 的(de)(de)(de)(de)(de)基(ji)準(zhun)(zhun))，在這(zhe)種(zhong)用(yong)(yong)(yong)法中，允許軟件憑借通(tong)(tong)道至通(tong)(tong)道的(de)(de)(de)(de)(de)固(gu)有(you)匹配，校正其他(ta)所(suo)有(you)通(tong)(tong)道。請(qing)注意(yi)，熱(re)敏(min)電(dian)(dian)(dian)(dian)阻器(qi)的(de)(de)(de)(de)(de)溫度(du)(du)(du)探(tan)頭(tou)不(bu)必(bi)以(yi)電(dian)(dian)(dian)(dian)池(chi)的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)位(wei)為(wei)基(ji)準(zhun)(zhun)，這(zhe)些探(tan)頭(tou)一般也不(bu)需(xu)要(yao) 12 位(wei)的(de)(de)(de)(de)(de)分辨率(lv)。這(zhe)類(lei)探(tan)頭(tou)通(tong)(tong)常(chang)適用(yong)(yong)(yong)于(yu)直接與(yu)微控(kong)(kong)制器(qi)連(lian)接，從而(er)留(liu)出高性能(neng)(neng) LTC6803 的(de)(de)(de)(de)(de)輔助(zhu)輸(shu)入(ru)(ru)，以(yi)實現(xian)(xian)要(yao)求(qiu)更加苛刻的(de)(de)(de)(de)(de)功(gong)能(neng)(neng)。

總之，在電(dian)池管理系統電(dian)路(lu)中需要考(kao)(kao)慮的因素有很多，特別是那些決定(ding)封裝(zhuang)限制(zhi)的因素。當(dang)封裝(zhuang)設計(ji)思想匯(hui)聚(ju)在一(yi)(yi)起(qi)時，考(kao)(kao)慮一(yi)(yi)下也有可能產生機械(xie)影響的電(dian)子線路(lu)與信息(xi)流(liu)的結(jie)構(例(li)如(ru)：連接器化和(he)導線數目) 同樣(yang)也是很重要。一(yi)(yi)旦(dan)權衡(heng)過這(zhe)些因素而且封裝(zhuang)設計(ji)思想成(cheng)(cheng)熟之后，只需直接插入一(yi)(yi)款采用 LTC6803 平臺，一(yi)(yi)個(ge)聲名(ming)卓(zhuo)著、可擴展和(he)具成(cheng)(cheng)本(ben)效(xiao)益的數據采集解決方案便大功(gong)告成(cheng)(cheng)了。