摘要
针对比能量为180 Wh/kg以上的18650型锂离子电池,对比不同正极材料、电解液、负极黏结剂和面密度的超低温-40℃放电性能,发现正极材料种类对超低温放电起主要影响作用。钴酸锂(Li Co O_2)材料以0.2 C放电,-40℃下(4.2~2.5 V)与常温下(4.2~3.0 V)的容量比为90.8%,优于LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2材料(二次颗粒为53.1%,单晶一次颗粒为30.9%)。LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2二次颗粒的粒径越小,-40℃放电性能越好;将电解液溶剂组分中碳酸二甲酯(DMC)替换为丙酸乙酯(EP),可将锂离子电池-40℃下0.2 C放电容量与常温0.2 C放电容量之比从47.6%提升至53.1%;负极黏结剂聚丙烯酸酯-40℃放电性能优于丁苯橡胶,且放电倍率增加,该优势表现更明显;相同材料体系下,减小面密度有助于提升-40℃放电性能。
The discharge performance at uhralow temperature -40 ℃ for 18650 type Li-ion battery with different cathode material,electrolyte, binder and coating density were compared, which had the specific energy of above 180 Wh/kg. The main influence factor of ultralow temperature discharge performance was the type of cathode material. When discharged with 0. 2 C, the capacity of lithium cobaltate （ LiCoO2 ） at - 40 ℃ （4. 2 - 2. 5 V） was 90. 8% compared with room temperature （ 4. 2 - 3.0 V ） , which was better than LiNi05 Coo 2 Mn0 3 02 materials （secondary particulate was 53.1% ,first particulate was 30. 9% ）. The smaller the particle size, the better the ultralow temperature discharge performance. Replaced dimethyl carbonate （DMC） with ethyl propionate （EP） in the solvent component of electrolyte, the capacity retention of Li-ion battery could be increased from 47. 6% to 53.1% when discharged at - 40 ℃. As the cathode binder of Li-ion battery, the ultralow temperature discharge performance of polyacrylate was better than that of SBR. In the same material system, the decrease of coating density was helpful to improve the uhralow temperature discharge performance.
作者
王珍珍
郭密
唐世弟
彭家新
WANG Zhen-zhen;GUO Mi;TANG Shi-di;PENG Jia-xin(Dongguan Sinowatt Co.,Ltd.,Dongguan,Guangdong 523696,China)
出处
《电池》
CAS
CSCD
北大核心
2018年第4期262-266,共5页
Battery Bimonthly
关键词
-40℃超低温放电
正极材料
电解液
黏结剂
面密度
- 40 ℃ uhralow temperature discharge performance
cathode material
electrolyte
binder
coating density
