The BEV cell supply contracts are/will be in the multi-billion USD size, as the BMW example shows.
Yup. They have to be. Just the plug-in hybrid market for BMW through 2020 will require billions of euros of batteries. As part of this past summer's announcements, BMW's statements did not include the time period for the multi-billions of euros agreement, but did say that they were going to increase the i series battery purchases by 25-30%. Most reports discuss the plug-in hybrid market through 2020 with 7% of the market.
For 2014, the i-series, using 15,000 vehicles x 19 kWh (optimistically throwing in i8's with smaller batteries but counting them as i3's) was about 0.285 GWh. At a 30% increase, BMW is looking at 20,000 vehicles with about 0.370 GWh per year, or about 80-100 million euros for 2015.
At 7% of BMW's sales, plug-in hybrid alone will be about 0.5 billion euros per year. So it won't take long to be multi-billions of euros.
In contrast, Tesla is bought around 2.6 GWh of batteries in 2014 or around $500 million USD. In 2015, this is likely to be a billion USD. Even at that purchase level, Tesla had to kick in money to accelerate the production of batteries. So on the same terms, the Tesla/Panasonic relationship is already in the billions of dollars or euros on an acquisition basis.
In order to build a 200 mile BEV, you need roughly 55 kWh of batteries on board and if you can get them at $200/kWh, it will be about $1.1 billion USD per 100,000 cars. That's 5.5 GWh of annual production. Tesla's average capacity per car is about 40% higher.
If you take all that together, the Samsung SDI/BMW relationship is a modest one in comparison to what Tesla/Panasonic is cooking up. It's not merely multi-billions over some unspecified period of years. It's billions now. You have to spend billions to make the battery plants right now. You have to spend a billion on the batteries right now.
And as I noted in an earlier link, it's doubtful that major additional economies of scale apply to battery plants beyond a certain size:
Green Car Congress: CMU/MIT study finds large-scale battery manufacturing will do little to reduce unit costs past a 200-300 MWh annual production level
OEMs could well decide to build regional battery plants in Asia, Europa and America.
Just because Tesla bulds one giant factory doesn't mean this is the only or best possible approach - especially since battery technology keeps progressing.
I've read through this paper when this was presented as evidence that the Gigafactory won't save costs. It doesn't say what you think it says. Primarily, it doesn't actually address any supply chain efficiency gains. Further, their methodology is definitely suspect, as it really doesn't look at manufacturing per se. Nothing OR related in a factory is really in that paper. It would be wrong to apply it directly to the real world of the Gigafactory.