The Mack Institute asks:
Before 1 January 2023, how many major automakers will debut a passenger vehicle powered by a solid-state battery?
Recent advances in battery technology, particularly solid-state batteries, could give rise to a new generation of electric vehicles (Car and Driver, Electrek. Some companies have announced plans to debut such vehicles, even if not necessarily for mass production yet (Road/Show, Digital Trends). For examples of vehicle debuts, see: CNBC, Axios. For the purposes of this question, "major automakers" refers to any of the 50 motor vehicle manufacturers included by the International Organization of Motor Vehicle Manufacturers in its 2017 list (OICA). A vehicle would not need to be solely powered by solid-state batteries to count.
NOTE 20 August 2020: For purposes of this question, for a vehicle to be considered "powered" by a solid-state battery it must be propelled, at least in part, by the use of a solid-state battery
NOTE 2 October 2020: For purposes of this question, a "passenger vehicle" is a motor vehicle with at least four wheels, used for the transport of passengers, and comprising no more than eight seats in addition to the driver's seat (http://www.oica.net/wp-content/uploads/stats-definition1.pdf).