Battery manufacturers and their recipes.
Originally Posted by MichaelPowell
Lithium batteries are well understood
Not as well as I think you believe. There are subtleties in the electrode structures and also in the electrolyte composition. All battery manufacturers have certain 'special sauces' that they add to their electrolytes to avoid electrode degradations, none share their recipes, and all are still perfecting and re-iterating them.
Bear in mind also that it is like lightbulbs. At the moment, battery manufacturers are still trying to make batteries they know will last. If they understood the batteries properly, they would design them to last for as long as the warranty and no longer.
There is no future to be made in making a commodity that will last forever - you will go out of business.