The company's announcement of a new car model drove investors into the stock.Several factors converged this week to make Chinese vehicle manufacturer Nio (NIO 1.97%) a popular stock in the somewhat battered electric vehicle (EV) sector. Almost unarguably the major one was the announcement of a new vehicle, although Tesla's (TSLA 3.49%) latest stumbles also played a role.It was an eventful few days for Nio, and since these developments were positive the stock rose. It ended the week more than 12% higher in p ...