【摘要】 锂电池的滥用导致热失控是造成电池安全事故的主要原因之一，也是亟须解决的问题。本文以E-51环氧树脂聚合物为基体，石墨烯纳米片为导电填料，聚酰胺为固化剂，制备了一种具有正温度系数（Positive Temperature Coefficient, PTC）的E-51环氧树脂/石墨烯复合材料，探讨了石墨烯含量、固化工艺对复合材料室温电阻率的影响，并研究了复合材料的可恢复性及对锂电池热阻断性能。结果表明，当石墨烯质量分数为15 wt%,固化温度为60℃,固化时间为3 h时，其室温表面电阻率为88Ω·cm,当测试温度升高至130℃时，复合材料的PTC强度达到1.6,并表现出可恢复性。将其应用在LiFePO₄电池中，在60℃测试温度下电池放电时间由70 min缩短至38 min,表现出优异的自激发热阻断现象。本研究有助于推动环氧树脂基PTC复合材料的应用，为解决电池因热失控而引发的安全事故提供借鉴意义。更多还原

【Abstract】 The thermal runaway caused by the abuse of lithium batteries is one of the main reasons for battery safety accidents and a key issue that urgently needs to be addressed. In this article, E-51 epoxy resin/graphene composite with a positive temperature coefficient（PTC） was prepared by using the E-51 epoxy resin as the matrix, graphene nanosheets as the conductive fillers and polyamide as the curing agent, respectively. The effects of conductive filler graphene content and curing process on the room temperature resistivity of the composite material is investigated. Meanwhile, the recoverability and thermal blocking performance of the composite material for lithium batteries is also studied. The results showed that when the mass fraction of graphene in the composite material was 15 wt%, the curing temperature was 60 ℃, and the curing time was 3 hours, the surface resistivity at room temperature was 88 Ω·cm for the E-51 epoxy rein/graphene composite. When the test temperature was raised to 130 ℃, the PTC strength of the composite material reached 1.6 and possessed recoverability. Applying the E-51 epoxy resin/graphene composite in the LiFePO₄ batteries, the discharge time of the batteries was shortened from 70 min to 38 min at 60 ℃, which exhibiting excellent self-excited thermal blocking phenomenon. This study contributes to promoting the application of epoxy resin based PTC composite materials and provides a reference for solving safety accidents caused by thermal runaway in batteries.更多还原