Early investors in electric-vehicle (EV) battery start-up QuantumScape (QS -0.48%) have had quite a ride -- and not the fun kind. The company went public via a merger with a special purpose acquisition company, or SPAC, in late 2020 and quickly zoomed to a valuation of around $54 billion. Investors were excited about the potential of a better EV battery and rushed to buy. That didn't last, of course. QuantumScape's market cap is now around$3 billion. But despite the stock's swoon, the investment case for t ...