Enhancing battery energy density is of particular importance for distributing electric vehicles and stationary uses. For EV uses, high energy density battery allows for longer driving distance per a charge, and cycle life, while it leads to an enlarged risk on safety. Hence, it exists a trade-off relationship between energy density and safety for battery packs developed for EVs.

Safety failure in the current lithium ion battery is often related to an explosion of a volatile and flammable electrolyte liquid. Once internal short takes place irregularly, joule heat generation takes place and thereby it leads to the explosion of volatile and flammable electrolyte as this called thermal runaway. In addition, fields of the battery used is limited, namely, the battery use in the enclosed space is likely to be prohibited to prevent the leakage of toxic and volatile electrolyte liquid into the space.

To overcome the issues related to the battery safety, we recently developed a novel electrolyte having a lower vapor pressure electrolyte than the conventional organic liquid electrolyte, and applied the electrolyte to lithium ion battery with a high energy density. A repeated operation of the battery was successfully demonstrated.

In this presentation, the concept our electrolyte, and evaluated results on electrolyte volatility and charge-discharge property of the battery will be reported.