I think some of those assumptions are off the mark a bit. eg. Tesla 85kg battery has 7104 cells @45g each. Discount that for the cathode, electrolyte, glue and packaging. Continue discounting for natural g vs synthetic g vs silicon. This is the biggest battery out there - most are around 16-18kwh. One billion vehicles on the road now with an average lifespan of 10 years. If you are really, really lucky there might be 500,000 sales in 2020. Price is the kicker. Environmentally not much change from running on petrol to running on coal. People do three things with their cars. Drive locally often - good for BEV, PV sales and battery storage, Sunday drive - not so good, drive interstate occasionally - bad ... ever seen 15 Tesla's in a queue waiting two hours for a charge?
Anyway, just read today that most people are not buying another xEV after owning one. As well pure EV market share declined in 2015 for the first time.
"According to Edmunds data, only 29 percent of people who traded in an electric-powered vehicle (including pure EVs and plug-in hybrid cars) this year went on to purchase another electric-powered vehicle."