Solid state batteries Batteries Solid Power Begins Manufacturing Prototype Solid-State Batteries Solid Power expects to begin supply solid-state battery cells to BMW and Ford later this year for testing and validation purposes. BySteve Hanley Published2 days ago The first mention of Solid Power and its plan to produce solid-state lithium-ion batteries in the CleanTechnica archives happened in 2017, when we reported it had formed a partnership with BMW to develop batteries with no semi-liquid electrolyte. Since then, Ford has also signed on as a major investor in the Colorado-based company.