高效提升電池壽命(ming)和安全性 | 基于ACM32 MCU的BMS應(ying)用方案(an)
電(dian)池(chi)管理系(xi)統(tong)(BMS)通過監控電(dian)池(chi)的狀態,智能化管理及(ji)維(wei)護(hu)各個電(dian)池(chi)單元,從而防止電(dian)池(chi)出現過充電(dian)和過放電(dian)。優質(zhi)的電(dian)池(chi)管理系(xi)統(tong)能夠最大限度地延長電(dian)池(chi)整(zheng)體使(shi)用壽命,有效保障設備安全。
BMS電池管理概述
BMS,即電(dian)(dian)(dian)池(chi)(chi)管理(li)系統(tong)(Battery Management System),隨(sui)著(zhu)鋰(li)電(dian)(dian)(dian)池(chi)(chi)的(de)(de)廣泛應用,BMS作(zuo)為鋰(li)電(dian)(dian)(dian)池(chi)(chi)的(de)(de)“保姆”也(ye)越來越被大眾所關注。相較于傳統(tong)電(dian)(dian)(dian)池(chi)(chi),鋰(li)電(dian)(dian)(dian)池(chi)(chi)具有更好的(de)(de)能力密度(du),更高的(de)(de)工作(zuo)電(dian)(dian)(dian)壓,更低(di)的(de)(de)放(fang)電(dian)(dian)(dian)率。但鋰(li)電(dian)(dian)(dian)池(chi)(chi)在面對過(guo)(guo)充(chong)、過(guo)(guo)放(fang)等問題(ti)時(shi),相對脆弱。由于鋰(li)電(dian)(dian)(dian)池(chi)(chi)組在生產(chan)制造(zao)和使(shi)用過(guo)(guo)程中存(cun)在的(de)(de)差異性,會導致電(dian)(dian)(dian)池(chi)(chi)單(dan)(dan)體(ti)(ti)之間天(tian)然就存(cun)在著(zhu)不一(yi)致性。這種不一(yi)致性主要表現在單(dan)(dan)體(ti)(ti)容(rong)量、內阻(zu)、自放(fang)電(dian)(dian)(dian)率、充(chong)放(fang)電(dian)(dian)(dian)效率等方面。單(dan)(dan)體(ti)(ti)的(de)(de)不一(yi)致,會進一(yi)步導致過(guo)(guo)充(chong)、過(guo)(guo)放(fang)等問題(ti),進而(er)造(zao)成(cheng)電(dian)(dian)(dian)池(chi)(chi)壽命(ming)下降甚至(zhi)死亡(wang)或(huo)損壞(huai)。
圖1 | 容量不一(yi)致時充放電過程示(shi)意圖
如圖1所示,由于電(dian)(dian)(dian)(dian)池(chi)單(dan)體(ti)(ti)的(de)差異,在充電(dian)(dian)(dian)(dian)時(shi)(shi),低容(rong)(rong)量(liang)電(dian)(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)(dian)已飽和,而較(jiao)大容(rong)(rong)量(liang)的(de)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)量(liang)未滿(man),此(ci)時(shi)(shi)對于小容(rong)(rong)量(liang)單(dan)體(ti)(ti)來說,則(ze)處于過充狀(zhuang)態。相反,放(fang)(fang)電(dian)(dian)(dian)(dian)時(shi)(shi),較(jiao)大容(rong)(rong)量(liang)的(de)電(dian)(dian)(dian)(dian)池(chi)仍然處于放(fang)(fang)電(dian)(dian)(dian)(dian)狀(zhuang)態,而小容(rong)(rong)量(liang)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)量(liang)已空(kong)。有研究表(biao)明,單(dan)體(ti)(ti)電(dian)(dian)(dian)(dian)芯20%的(de)容(rong)(rong)量(liang)差異,會帶來超過40%的(de)容(rong)(rong)量(liang)損失。
而BMS模塊則是為避免該問題(ti)的(de)(de)出(chu)現(xian)而存在(zai)。BMS會實時(shi)監測單體(ti)的(de)(de)容(rong)量,并采用電(dian)池均衡手段來(lai)(lai)保證電(dian)池的(de)(de)正常(chang)工(gong)作(zuo)(zuo)。將不(bu)同容(rong)量的(de)(de)單體(ti)比(bi)作(zuo)(zuo)體(ti)積不(bu)同的(de)(de)水(shui)(shui)桶,而電(dian)池的(de)(de)電(dian)量好比(bi)是水(shui)(shui)桶中存留的(de)(de)水(shui)(shui)。充放(fang)電(dian)時(shi),BMS會將快滿的(de)(de)“水(shui)(shui)桶”里面的(de)(de)“水(shui)(shui)”轉移到較空的(de)(de)“水(shui)(shui)桶”中,以此來(lai)(lai)保證整體(ti)電(dian)池電(dian)量的(de)(de)均衡,避免出(chu)現(xian)過充和(he)過放(fang)的(de)(de)問題(ti)。如(ru)圖2所示。
圖2 | BMS電(dian)池均衡示意圖
上海(hai)航芯BMS應用(yong)方(fang)案
上海(hai)航(hang)芯(xin)推出的(de)(de)BMS應用(yong)方案(an),采用(yong)ACM32F403/ACM32G103系列MCU作為主(zhu)控芯(xin)片,最(zui)高(gao)工(gong)作頻(pin)率可達180MHz/120MHz,內置最(zui)大(da)512KB的(de)(de)eFlash和(he)最(zui)大(da)192KB SRAM,滿(man)足一般BMS算法庫的(de)(de)需求。內置2Msps/3Msps采樣率12位ADC,實現(xian)對電(dian)芯(xin)電(dian)壓、電(dian)流、溫度等(deng)信號的(de)(de)高(gao)頻(pin)采樣。具有USB/UART/CAN/SPI等(deng)多種(zhong)通訊(xun)接口(kou),足以應對大(da)多數(shu)應用(yong)場合(he)(如(ru)需要(yao)485通信的(de)(de)兩輪(lun)電(dian)動(dong)車,需要(yao)CAN接口(kou)的(de)(de)新能(neng)源(yuan)汽(qi)車等(deng))。基(ji)于ACM32F403/ACM32G103的(de)(de)BMS方案(an)結構示(shi)意(yi)圖(tu)如(ru)下圖(tu)所示(shi):
圖(tu)(tu)3 | BMS系統框圖(tu)(tu)
ACM32F4/ACM32G1主控芯片,通(tong)過ADC對敏感(gan)信號進行(xing)采樣(yang),并(bing)依照BMS算法庫計算得到當前電池的(de)SOC、SOH等(deng)數(shu)據,執行(xing)均衡以及(ji)熱管理控制,保證電池處于正常(chang)的(de)工作(zuo)狀態。當出現問題時,支持在線(xian)警報同時給出LED指示信號。整個系統的(de)運行(xing)參數(shu)可(ke)以通(tong)過CAN/USB/UART等(deng)接(jie)口進行(xing)上報。