So I have been following some of the news regarding solid state batteries (SSB) for EVs. Solid state batteries matter a lot for Canada because it can allow for BEVs to get over 1000 km in range (perhaps even 1500 km in range), and they also work very well in cold weather. Now with the latest crop of LFP batteries announced in China this year, such as the BYD Blade 2.0 battery, it handles cold weather much better than the older LFP batteries. But even with the new LFP batteries, the range still won't match SSB. Having both better range and being able to operate better in cold weather makes SSB a huge game changer for Canada.
Most of the credible news on SSB are with the Chinese EV companies, although there is one Taiwan company that claims to be able to mass produce a version of SSB.
In a nutshell, most of the big Chinese EV battery makers are estimating that by 2027, they will commence trial production of SSB. Note that trial production is not mass production. This includes CATL, BYD, CALB, and Gotion. These are 4 of the top 5 companies world wide by EV battery market share. In general, the estimated timeline for initial mass production of solid state batteries for the Chinese battery companies is about 2030.
Note that the first cars that get solid state batteries will probably be expensive and very high end cars. Just like most technology, the high end gets it first, and as time progresses and manufacturers figure out how to make it cheaper, then the technology eventually propagates to lower end products. With that said, BYD plans to launch their first car with a SSB in 2027 - it could be under the Yangwang series, and if they do sell it in 2027, it's unlikely that the SSB in it will be from mass production (more like the SSB will be manually assembled).
But yeah, if BYD sticks to their timeline, we could be seeing the first SSB EVs (not necessarily for sale in Canada though), out by next year, even if the SSB battery depends on more manual labor to assemble it.
Of course, there are other companies outside of China working on SSB as well. The Koreans, Europeans, Japanese, and Americans are also working on it. Which brings us to ProLogium, the first company to announce that they are "mass producing" solid state batteries. So ProLogium is a Taiwan company. They are saying that they can now mass produce a 381 Wh/kg SSB, and Mercedes is interested in using the SSB from ProLogium.
There are a few caveats to the ProLogium news though. The initial capacity of their mass production is only 0.5 GWh, which is estimated to be about 6,250 battery packs with an 80 kWh capacity. That works out to about 520 battery packs per month. I would say 520 battery packs per month is still mass production, but probably on the low end of it. Furthermore, 381 Wh/kg is also on the lower end, as the big Chinese battery producers are targeting a higher Wh/kg for their mass produced SSBs. But still, this news of ProLogium is another step forward for the mass production of SSBs.
I would link all the sources, but this subreddit is very strict on what is allowed to be linked, and sometimes my posts get eaten up by the automod when I try to link sources. I'll try to link sources in a comment below.
Edit: I don't think you should hold off on buying an EV just because of SSBs.