One that appears to have slipped under many radars is the 'flowcell' EV system. Yet now might be the time to take interest in it, as Autocar is reporting a production-ready flowcell car is now more likely.
First, a brief explanation of what a 'flowcell' powertrain does. Essentially an electric powertrain, the battery technology can be replenished through an onboard supply of positively and negatively charged liquids, which would make the system more effective for a majority of road users. And it's a more refined, energy-dense iteration of this setup that Nanoflowcell has developed and demonstrated in its 'Quantino' and 'Quant FE' prototypes. Even more interestingly, it now appears the system may be heading to a road car, as a "large manufacturer that is not German" has expressed interest in Nanoflowcell's rather clever system.
Even if this technology isn't adopted by the anonymous corporation, Nanoflowcell is optimistic about the chances of this technology being fitted to customer cars. There's scope, for instance, of having the technology licensed to other brands in a not-too-dissimilar way to how Gordon Murray envisioned his iStream production process, and Nanoflowcell has developed prototype vehicles that not only work for sustained periods of time, but are completely road legal in their native Germany. So, while the concept of a water-recharged electric car is still a bit of an odd one, there's every chance that the Nanoflowcell system could find its way into a production car sooner rather than later.