热封条件及氛围对蓄电池壳体力学性能的影响

Effect of Heat-Sealing Conditions and Atmosphere on Mechanical Properties of Lead-Acid Storage Battery Jar

采用热焊法制备了蓄电池专用PP样条,利用改变热封条件和气体氛围对PP材料的结晶行为、热稳定性能和力学性能进行了深入研究。DSC和偏光显微镜结果表明,样品的有效热封温度应不低于172.3℃,而热封后冷却温度应不高于117.5℃。TGA结果表明,与空气氛围下相比,样品在氮气氛围下的热稳定性较好,初始分解温度可达366℃。扫描电镜结果表明,氮气氛围下,样品具有更粗糙的断面且没有出现气孔(空气氛围下出现)。力学性能测试结果表明,与空气氛围下相比,在氮气氛围下,样品的拉伸强度较高,并且,随着热封温度、焊接时间和保压时间的增加,呈先升高后降低的趋势。综合以上结果可以得到最佳的热封条件为氮气氛围、热封温度为340℃、焊接时间为5 s、保压时间为5 s。

The PP sample for storage battery was prepared by hot-welding method,and the crystallization behavior,thermal stability and mechanical properties of PP were studied by changing the heat sealing conditions and gas atmosphere.The results of DSC and polarizing microscope revealed that the effective heat-sealing temperature of the sample should not be lower than 172.3℃,and the cooling temperature after heat sealing should not be higher than 117.5℃.The TGA results showed that the initial decomposition temperature of the sample in nitrogen atmosphere was 366℃,which was much better than that in air atmosphere.SEM results showed that the sample had a rougher cross-section and no air pores in nitrogen atmosphere.The mechanical test results showed that the tensile strength of the sample in nitrogen atmosphere was obviously higher than that in air atmosphere,and it firstly increased and then decreased with the increase of heat-sealing temperature,sealing time and pressure holding time.Thus,the optimal condition for the mechanical properties of heat-sealed PP material was that the heat-sealing temperature was 340℃,the heat-sealing time was 5 s,and the pressure holding time was 5 s.