"Solid state batteries replace the semi-liquid electrolyte with a solid substance that is far more tolerant of high heat and less susceptible to damage in the event of a collision. In the lab, they have a higher energy density, can charge faster, and weigh less than traditional lithium-ion batteries. Not only do they cost less, they may require simpler, less costly cooling systems and could allow automakers to dispense with the heavy, bank vault quality safety cages used today to prevent damage to traction batteries in the event of a collision. Those two factors alone could lower the cost of manufacturing electric vehicles, making them affordable for more drivers."