QuantumScape (QS -3.78%) stock had a monster one-day trading session in the first week of the year when it shot up by more than 40% on Jan. 3. Shares of the solid-state battery technology start-up, however, gave all of that back and then some, and are now down 6% for the year. QuantumScape stock has fallen by a double-digit percentage this week, and was trading 14% lower for Friday's session as of 10:15 a.m. ET. QuantumScape's early January surge came after its largest partner and investor reported hugely e ...