Compared to the lithium-ion batteries used in the current crop of EVs, solid-state units promise better range, quicker charging times, and a longer battery life.

Pratt outlined a couple of reasons why Toyota intends to debut solid-state batteries in hybrids. Solid-state batteries are, at the moment, more expensive to produce, he said, and since hybrids have smaller battery packs than EVs, implementing them in hybrids first will reduce the cost. The other challenge facing solid-state batteries currently is battery life, with repeated charging taking a toll on early prototype batteries. In a hybrid, the smaller battery is charged and recharged far more often, and Pratt suggested that the increased amount of cycling for the batteries will make hybrids a good test bed for the new technology.