Toyota has been trying to make solid state batteries work for vehicles, but they aren't doing any EVs unless they are compelled to: their plans are for "electrified" cars -- that is hybrid, hydrogen and, maybe, EV, where regulators force them to. They have made it abundantly clear that they are not interested in EVs, presumably because that lowers maintenance revenue.
When it comes to solid state there are a lot of interested parties researching it. As they should. But the hype has been hot and hard for years and shows no signs of letting up. Just as a recent example [2]:
"could be ready within a few years" -- yeah, sell $TSLA because in a few years there
could be an improvement in battery technology. Of course, next year Tesla is planning on talking about
their battery developments, but that isn't important.
As for summer games, I guess you are referring to this [1]:
Wow. "if possible" "we would like". Maybe someone who is more knowledgeable about Japanese culture can help me, but to a westerner those weasel words completely undermine the statement and suggest a more accurate/honest statement would read, "After nearly ten years of minimal results from research into solid state batteries we hope to demonstrate a proof-of-concept low capacity battery for a hybrid."
So Toyota, notorious for resisting any EV production is
finally talking about making some. For China (and Europe). Because they have to. [3]
So Toyota will start making these solid state battery powered EVs next year? The same year they plan on revealing their first public demo of a solid state battery? Or perhaps this has to do with the Toyota/Panasonic partnership and nothing to do with a not-yet-ready-for-use-in-an-EV solid state battery? [4]
I seem to have lost the links I had for tracking actual progress on solid state batteries, but to give an idea about how difficult they are to develop: [5]
Toyota (and many others) have been researching solid state for many years now. Maybe a breakthrough against the fundamental constraints that prevent them being useful for EVs has been made. Maybe. In the meantime, Toyota's 10-year plan is expiring and they have to show
something for it. But it appears that the EVs they are forced to make will be powered by lithium-ion prismatic cells made by Panasonic.
1)
Toyota accelerates target for EV with solid-state battery to 2020
2)
Solid-State Batteries Could Power Electric Vehicle Breakthrough
3)
New Solid-State Battery Developed for Lexus Electric Vehicles
4)
Toyota and Panasonic confirm wide-ranging new battery partnership for electric vehicles - Electrek
5)
Who Will Win the Race for an EV Solid-State Battery?