CMC水刺复合镍氢电池隔膜的研究

发布时间：2018-04-19 23:10

  本文选题：CMC隔膜 + 镍氢电池　； 参考：《东华大学》2015年硕士论文

【摘要】：镍氢电池是一种新型化学电源，具有比能量高、安全性能好、良好的循环充放电性能等优点，被确定为近期和中期的首选动力电池。隔膜作为镍氢电池的重要组成部分，其优劣直接影响到电池的容量、放电电压、自放电等性能。我国隔膜的生产尚处于初级阶段，绝大多数高性能镍氢电池采用进口隔膜，因此开发高性能电池隔膜、改善我国隔膜生产技术对我国电池能源的应用具有重要意义。 基于非织造材料的吸液过程符合毛细吸水差动效应的特点，本课题采用熔融共混的方法将亲水性添加剂CHA与聚丙烯（PP）切片制备成亲水熔喷基布（Meltblown,简称M），对比分析其与商业纯PP熔喷基布的性能差异；然后将经过开松梳理制备的PP短纤维网（Cardingweb，简称C）与熔喷基布按照短纤维网/熔喷/短纤维网的次序叠合，叠合纤维网再经水刺复合和热轧处理成型为外层孔径大、内层孔径小的CMC复合隔膜，并分析水刺压力、热轧温度、热轧时间及热轧压力对CMC复合隔膜性能的影响，最后选取商业磺化隔膜作参照样，对比分析几类隔膜的性能及其装配的电池的循环性能和储存性能。 本课题通过以上研究，得到如下结论： （1）相比纯PP熔喷基布，亲水熔喷基布结构蓬松，拉伸强力低，具有良好的浸润性能和吸液性能。 （2）CMC复合隔膜的拉伸强力随着最大水刺压力的增加先增加后减小，且都能够满足电池对隔膜的要求；CMC复合隔膜的厚度、透气率、吸碱率随着最大水刺压力的增加而减小，吸碱率都超过500%，优于一般商业隔膜；综合水刺工艺对CMC各项性能的影响，最佳水刺工艺为：水针板至输网帘的距离为20mm，，输网帘速度2m/min，预水刺压力为25bar，正反各水刺两道，最高水刺压力为40~60bar。 （3）热轧处理后，CMC复合隔膜的密度增加，厚度、孔隙率、最大孔径、平均孔径等性能明显减小，能够满足电池对隔膜的要求，且CMC复合隔膜的透气率和吸碱率也随着热轧温度、热轧时间及热轧压力的增加而呈现减小的趋势；热轧温度是影响CMC隔膜综合性能的关键因素，其合适的范围为80~90℃，考虑到经济成本，热轧时间和热轧压力分别采用15s和1MPa。 （4）相比商业磺化隔膜，CMC复合隔膜表现出良好的化学稳定性和吸液性能，其耐碱损失率不超过1%，中间层为纯PP熔喷基布的CMC隔膜的吸碱率与商业磺化隔膜相差不多，表明CMC复合隔膜的外层孔径大、内层孔径小的结构利于提高其吸液性能。 （5）中间层为纯PP熔喷基布的CMC复合隔膜组装的电池的最大放电比容量最小，仅为202.6mAh/g，商业磺化隔膜装配的电池的放电比容量最大，为282.6mAh/g，中间层为亲水熔喷基布的CMC复合隔膜组装的电池的最大放电比容量随着CMC复合隔膜熔喷层中CHA添加比例的增加而增大；CMC复合隔膜组装的电池的放电比容量保持率较好，存储30天后的自放电率低，表现出更加优越的存储性能。 通过三类隔膜结构性能和电池性能的对比可以得出，亲水熔喷基布制备的CMC复合隔膜因具有良好的保液性能和化学稳定性，使得其组装的电池表现出更佳的循环性能和储存性能。因3种亲水熔喷基布制备的CMC复合隔膜差异不大，考虑经济成本，CHA添加比例为5%更适宜商业生产。
[Abstract]:Nickel - hydrogen battery is a new type of chemical power supply , which has the advantages of high specific energy , good safety performance , good cycle charge - discharge performance and so on . The diaphragm is an important part of nickel - hydrogen battery . Its advantages and disadvantages directly affect the capacity , discharge voltage and self - discharge performance of the battery . The production of diaphragm in China is still in the primary stage . Therefore , it is of great significance to develop high - performance battery diaphragm and improve the technology of diaphragm production in China .

Based on the characteristics of capillary water absorption differential effect , the hydrophilic additive CHA and polypropylene ( PP ) were prepared by melt blending method .
then the PP short fiber web ( C ) prepared by opening and carding and the melt - blown base cloth are laminated according to the order of the short fiber web / meltblown / short fiber web , the laminated fiber net is formed into a CMC composite diaphragm with large outer diameter and small inner diameter by hydroentanglement and hot rolling treatment , and the influence of the water spike pressure , the hot rolling temperature , the hot rolling time and the hot rolling pressure on the performance of the CMC composite diaphragm is analyzed , and finally , the commercial sulfonated diaphragm is selected as reference sample , and the performance of the diaphragm and the cycle performance and storage performance of the assembled battery are compared .

Based on the above study , the following conclusions are obtained :

( 1 ) Compared with the pure PP melt - blown base cloth , the hydrophilic melt - blown base cloth has a fluffy structure and a low tensile strength , and has good wetting performance and liquid - absorbing performance .

( 2 ) the tensile strength of the CMC composite diaphragm increases with the increase of the maximum water spike pressure , and can meet the requirement of the battery to the diaphragm ;
The thickness , air permeability and alkali absorption rate of CMC composite diaphragm decrease with the increase of the maximum water spike pressure , and the alkali absorption rate is more than 500 % , which is superior to the general commercial membrane ;
The effect of the comprehensive water needling process on the properties of CMC is that : the distance between the water needle plate and the transmission screen is 20 mm , the speed of the transmission screen is 2 m / min , the pre - water spike pressure is 25 bar , the front and back each water spike is 2 channels , and the maximum water spike pressure is 40 to 60 bar .

( 3 ) After hot rolling treatment , the density of CMC composite diaphragm increased , the thickness , porosity , the maximum pore diameter , the average pore diameter and the like were obviously reduced , the requirement of the battery to the diaphragm can be met , and the air permeability and the alkali absorption rate of the CMC composite diaphragm also show a decreasing trend with the increase of hot rolling temperature , hot rolling time and hot rolling pressure ;
The hot rolling temperature is the key factor which affects the comprehensive performance of CMC diaphragm . Its suitable range is 80 锝

本文编号：1775145