EPDM阻燃热防护材料在锂离子电池热失控中的研究

研究了三元乙丙橡胶(EPDM)阻燃热防护材料配方中的阻燃剂、厚度对其性能的影响,以及在锂离子电池中的应用效果.结果发现具有阻燃配方的EPDM的背面温度低于未加阻燃剂的EPDM,随阻燃剂的加入和样品厚度的增加,EPDM的背面温度降低、阻燃性能提高.在火源温度为500℃的条件下,厚度为3,6 mm加阻燃剂的EPDM的稳定温度分别为185.1,165.7℃.选用厚度3 mm的阻燃EPDM作为锂电池组的热防护材料,电池热失控过程中仅1块电池发生爆炸,而未进行热防护的电池组中共有5块电池相继发生爆炸.以电池组为中心,在无热防护的锂电池组燃烧爆炸实验时,距电池组半径30 cm处圆形区域温度均受到电池燃烧爆炸的影响而达到高达300℃的高温,属于十分危险的范围;而在使用EPDM热防护材料对锂离子电池进行防护后,此区域的温度在20～28℃之间浮动,属于十分安全的温度范围.

EPDM Flame Retardant & Thermal Protection Material in Thermal Runaway of Lithium-ion Batteries

The effects of flame retardant and material thickness on the properties of ethylene propylene diene monomer (EPDM) flame retardant thermal protection materials were investigated, and the application of flame retardant EPDM in the lithium-ion battery pack was evaluated. Results show that, the back temperature of EPDM with flame retardant is lower than the temperature of EPDM without flame retardant, the back temperature of EPDM decreases and the flame retardant performance improves with the load of flame retardant and the increase of sample thickness. When the ignition temperature is 500℃, the final stable back temperatures of EPDM with a thickness of 3 mm and 6 mm are 185.1℃ and 165.7℃ respectively. Taking the flame retardant EPDM with 3 mm thickness as the protection of the lithium-ion battery pack, a thermal runaway test was carried out. The test results show that, only one battery explosion occurs with thermal protection, and all five batteries explode without thermal protection in the battery pack. And then, taking a battery pack as the center of the area coverage, an explosion experiment of the lithium-ion battery pack was completed to analyze the thermal protection effect of flame retardant EPDM. The results show that, the temperature of the battery pack in the surround region about the radius 30 cm can be affected by the explosion of the battery without thermal protection of flame retardant EPDM, causing the field temperature up to 300℃, being very dangerous. After protecting the lithium-ion battery with EPDM thermal protection material, the temperature in this area fluctuates between 20~28℃, which is a very safe temperature range.