(1. 中南大學(xué) 冶金與環(huán)境學(xué)院，長沙 410083； 2. 湖南艾華集團股份有限公司，益陽 413000； 3. 全固態(tài)儲能材料與器件湖南省重點實驗室，益陽 413000)
摘 要: 基于電化學(xué)熱耦合模型，定量分析了磷酸鐵鋰動力電池不同倍率放電下正負極歐姆極化、濃差極化和活化極化。結(jié)果表明：1C放電初期，正極固相濃差極化波動最大，峰值達到147 mV；放電中期，各類型極化變化曲線較為平穩(wěn)，活化極化最大，約為48 mV；放電末期，負極活化極化和負極固相濃差極化迅速增大；8C放電末期，正極固相濃差極化急劇增加，達到715 mV。提高放電倍率，活化極化的大幅增加是高倍率下極化嚴重的最主要原因，且負極活化極化的增加幅度比正極活化極化更大；而減小負極顆粒粒徑可以有效減小負極活化極化。
關(guān)鍵字: 鋰離子電池；歐姆極化；濃差極化；活化極化；數(shù)值仿真
（1. School of Metallurgy and Environment, Centre South University, Changsha 410083, China; 2. Aihua Group Co., Ltd., Yiyang 413000, China; 3. Hunan Provincial Key Laboratory of All-Solid-State Energy Storage Materials and Devices, Yiyang 413000, China）
Abstract:An electrochemical-thermal model was developed to quantitative analysis ohmic polarization, concentration polarization and activation polarization of positive and negative electrodes at different discharge rates. The results show that concentration polarization of positive is the main constituent part at the beginning of 1C rate discharge, which also shows the biggest fluctuation range. Various polarizations change less in the middle of 1C rate discharge, but at the end ohmic polarization and activation polarization of negative rapidly increase. Concentration polarization of solid phase in positive electrode increases dramatically to 715mV at the end of 8C rate discharge. The aggravation of activation polarization is the main cause of large polarization with discharge rate raised, and the activation polarization of negative electrode is worse than that of positive. It is effective to remit activation polarization of negative by reducing particle sizes of negative electrode.
Key words: lithium ion battery; ohmic polarization; concentration polarization; activation polarization; numerical simulation
