I have a few thoughts on this [some good thoughts....]
The optimum thing for Tesla is that the Gigafactory is a pure cost centre, 100% vertically integrated, with nobody pulling out profits at the cell manufacturing step, all profits pulled at the final value add step: Finished cars, finished storage products.
Therefore the natural way to sell this opportunity to a partner like Panasonic would be to issue Panasonic a load of TSLA shares and have them take their profits on those shares. But that isn't apparently what is happening here. Panasonic apparently is willing to put $1.6 billion directly into the Gigafactory plus a load of IP and market leverage to get the job done - and the aim of that job is disproportionately in Tesla's interests and that is to reduce the cost of the very product Panasonic makes money from selling. It's mind-blowing. Deal of the century is I think a literal description here.
I think, and I am reasonably confident in this, that the cell chemistry is Tesla's IP, not Panasonic's, at the very least it is a proprietary Panasonic / Tesla collaboration on the chemistry that Panasonic is not free to sell to third parties. Same with the cell design - on the latter point Tesla has patents, open source yes, but it is proof positive of Tesla IP at the cell level. Tesla has the ability to use Samsung and LG to produce Tesla-specified cells.
While I get the idea you presented that Panasonic may see an opportunity to trade margins for volume it does not in my mind fully explain Panasonic conceding control of its own destiny implicit to retaining a suppler / customer relationship. Why not just insist Tesla invests in Panasonic battery capacity expansion in return for passing on a percentage of cost savings realized.
Tesla has obviously demonstrated to Panasonic that Tesla is the world's largest battery customer and that its plans to become much bigger are credible. No other car maker can prove that to itself or its shareholders let alone to a large cell maker. Not even Nissan or Toyota.
Tesla could make the credible threat that it would just partner with Samsung or LG on the Gigafactory if Panasonic did not cooperate and Tesla created credible leverage by raising Gigafactory funding independently of securing a battery partner.
But still, why do it. That threat posture only applies to a Tesla promise to max-out Panasonic Japan's capacity and the possibility of withdrawing that custom. The natural response from Panasonic to a pure threat posture would be to halt supply now until Tesla backed off because Tesla cannot sell anything without Panasonic's cooperation at present and even a temporary stand-off with Panasonic right now would be catastrophic for Tesla. This by the way is the standard of leverage battery suppliers have with the remainder of the auto industry and giving up leverage like this is not something any competent negotiator gives up lightly.
There must be a carrot in there somewhere and as previously described, the last place to look ought to be extracting profits at the cell manufacturing level because that just hurts the entire process including ongoing competitive advantage and attainable growth rate.
My view on this, and still this is a long shot, is that the really big carrot in this deal is not selling more cells but selling more Gigafactories - whereby Panasonic would be a natural lead contractor to national Gigafactories the world over.
This is a very very real carrot, but one hell of a sales job to get anyone to see an opportunity that large and that many chess moves away that needs to pass through a valley of death period of giving up control as a profit center making cells whether that global Gigafactory contractor opportunity materializes or not.
Perhaps I underestimate the Japanese - they do have a habit of thinking in chunks of 20 years or more and less in the here and now more typical of the West. The bottom line here is that this Gigafactory deal is far and away the most significant and the most brilliant deal I have ever heard of.
