Hyojung Yoon

Mitigating thermal runaway of lithium-ion battery through electrolyte displacement

Alkanes are investigated as thermal-runaway retardants (TRR) for lithium-ion battery (LIB). TRR is a chemical that can rapidly terminate exothermic reactions in LIB. Under normal working conditions, TRR is sealed in separate packages in the LIB cell, and upon mechanical abuse, it is released to suppress heat generation. The alkanes under investigation include octane, pentadecane, and icosane, among which pentadecane has the highest thermal-runaway mitigation (TRM) efficiency. In nail penetration test on coin cells, ∼4 wt. % pentadecane reduced the maximum temperature by ∼60%; in impact test on pouch cells, ∼5 wt. % pentadecane reduced the maximum temperature by ∼90%. The high TRM efficiency of pentadecane is attributed to its high wettability to separator and its immiscibility with electrolyte. By forming a physical barrier between the cathode and anode, pentadecane interrupts lithium ion (Li+) transport and increases the charge transfer resistance by nearly two orders of magnitude. The diffusion rate of ...

Effects of electrode pattern on thermal runaway of lithium-ion battery

In the current study, through a set of nail penetration and impact tests on modified lithium-ion battery coin half-cells, we examine the effects of electrode pattern on the heat generation behaviors associated with internal shorting. The results show that the temperature profile is quite insensitive to the openings in cathode layer, which may be attributed to the high specific energy as well as the secondary conductive paths. This finding will considerably influence the study in the area of thermal runaway mitigation of energy storage systems.

Internal short circuit mitigation of high-voltage lithium-ion batteries with functional current collectors

The safety of lithium-ion battery (LIB) becomes increasingly critical as the specific energy and cell capacity rapidly increase. Based on the modified current collector technique recently developed for nickel–cobalt–manganese active materials, here we investigate high-energy LIBs based on functional current collectors (FCC). Two high-voltage active materials were tested in our experiments: lithium-rich layered oxide (LRLO) and lithium nickel manganese oxide (LNMO). At the same time as a fully charged LIB cell is damaged, FCC isolates the internal short circuit (ISC) from the undamaged area; hence, the ISC-induced heat generation is drastically reduced to a negligible level. The electrochemical performance of FCC-based cells is nearly identical to that of reference cells.