While Toyota is working hard to bring its hydrogen fuel cell cars to fruition, they haven’t left lithium-ion battery technology entirely.
Even though most of Toyota’s hybrid fleet is still nickel-metal hydride (NiMH), energy density has forced the company to adopt lithium-ion battery technology in the Toyota Prius Plug-In. in comparison to NiMH, lithium-ion is about 50% more dense, increasing hybrid battery capacity without increasing weight. Still, lithium-ion battery packs have a couple drawbacks, besides their low density in comparison with newer technologies. For example, lithium-ion battery fires causes some stir in the news, which Tesla Motors and Boeing seem to have at least addressed.
Still, perhaps the only way to really address the inherent flammability of lithium-ion batteries is to develop a non-flammable replacement. Solid-state lithium-ion battery technology isn’t flammable, which is good news, but its low energy density has been an obstacle to its development. Improvements in this area have been promising, and a new prototype cell, developed by Toyota, exhibits similar energy characteristics to standard lithium-ion cells.
The new solid-state lithium-ion battery, made up of Li10SnP2S12 and Li11Si2PS12, achieves an energy density of 400 Wh/ℓ (watt-hours per liter). Future portable devices, including electric vehicles, may benefit greatly from such a battery, since they’re non-flammable and very stable. Additionally, since the materials are earth-abundant, they should be cheaper to produce.
Image © Toyota