Thermally conductive separator with hierarchical nano/microstructures for improving thermal management of batteries

Abstract

Thermal management is critical to improving battery performance and suppressing thermal runaway. Besides developing external cooling technologies, it is important to understand and control thermal transport inside batteries. In this paper, heat transfer inside batteries is first analyzed and the thermal conductivity of each component is measured. The results show that low thermal conductivity of the separator is one major barrier for heat transfer in Li-ion batteries. To improve thermal conductivity of the separator, a hierarchical nano/micro-Al2O3/polymer separator is prepared with thermal conductivity of ~1 W m-1 K-1 , representing an enhancement of 5 X compared to commercial polyethylene-based separators. Modeling has been performed to understand mechanism behind the enhancement of thermal conductivity, which suggests that addition of nanoparticles significantly reduces thickness of polymer coating on micronsized Al2O3 particles and thus increase the thermal conductivity of the composite separator. This Al2O3-based separator also has similar ionic conductivity with commercial polymer separators. Such composite separator may have potential applications in developing batteries with better performance and safety.

Measurement of Multiscale Thermal Transport Phenomena in Li-Ion Cells: A Review

“…Thermal property measurements are primarily done either at material level or at the cell level in Li-ion cells. At material level, the thermal property measurements of electrodes [45][46][47][48][49], electrolyte [50], separator [51,52], electrode stack [46,53], and contact thermal resistance [54,55] have been reported. Such material-level measurements are key in understanding the heat transfer inside a Li-ion cell and in determining the rate-limiting heat transfer processes.…”

“…Cross-plane thermal conductivity of electrodes and separators has been measured using a differential steady-state method [52]. The experimental setup is very similar to that of the 1D heat flowmeter previously used [45].…”

“…The experimental setup is very similar to that of the 1D heat flowmeter previously used [45]. The cross-plane thermal conductivity of positive electrode (PE), negative electrode (NE), and separator is measured to be 2.0, 1.06, and 0.19 W/m K, respectively, in the presence of electrolyte [52].…”

Superior thermal conductivity of poly (ethylene oxide) for solid-state electrolytes: A molecular dynamics study

“…Yang et al measured and identified that the separator is a major limiting factor for heat dissipation in liquid state LIBs, therefore a hierarchical polymer separator was prepared to obtain higher thermal conductivity. 12 A novel system that incorporates phase-change material was proposed to store and utilize the heat generated inside LIBs. 13 However, thermal transport inside SSLIBs is less investigated.…”

New Insights into Nail Penetration of Li‐Ion Batteries: Effects of Heterogeneous Contact Resistance

“…Rechargeable Li‐ion batteries are critical to various applications, such as portable electronics, vehicle electrification and grid‐level energy storage . However, Li‐ion batteries have low thermal stability and can explode when they are exposed to abusive conditions such as mechanical deformation, short circuit, over‐charging and external heating . Such instability originates from the high flammability of organic electrolyte and becomes more severe upon the pursuit of batteries with high energy density .…”