So far all of the Model Ys
So far all of the Model Ys delivered in Europe have been manufactured at Giga Shanghai. The batteries, which are built by Tesla, contain Tesla designed 2170 cells manufactured by LG Energy Solutions in China. Very soon Tesla will begin to manufacture Model Ys at Giga Brandenburg but, because of the glitch in manufacturing 4680 cells, the batteries will still contain LG 2170 cells shipped from China.
While "The range increase isn't from the 4680 battery cells" it is not "because those are going to come from Fremont and Giga Texas to start with. Eventually, Giga Berlin and Giga Shanghai will have battery factories that can produce them, but it won't be for a year or more most likely." There is a pilot plant producing 4680 cells on Kato Road in Fremont but at full scale production 4680 cells for vehicles built there will be manufactured by Panasonic at Giga Nevada where Tesla will build structural batteries containing them. Giga Brandenburg, as well as Giga Texas, was supposed to be producing 4680 cells by now and the equipment to do so is already in place but there was a glitch that as far as we know has not yet been fixed so Tesla switched to the backup plan where the two new plants will initially build non-structural batteries containing 2170 cells manufactured by LG in China for Brandenburg and Panasonic in Nevada for Texas. When this was announced on the Q2 2021 earnings call Elon Musk said "I mean, my guess is, more likely than not, above 50% of reaching a hundred gigawatt hours a year [of 4680 cell manufacture by Tesla itself at the two new plants] by the end of next year on annualized rate. Something like that." To put that in perspective, Panasonic production of 2170 cells at Giga Nevada in 2021 was less than 40 gigawatt hours.
My guess is that the range improvement is due to software changes.