If you think of electric cars, the first company name you are likely to bring to mind is Tesla (TSLA -3.67%). But Tesla most certainly isn't the only electric vehicle (EV) company or the only company making cars powered by alternative energy sources (including hybrids that use both carbon fuels and electricity). And there is a growing competitive threat that investors might not know about because it operates mostly in China.Tesla is growing fastTo be fair, there is good news coming out of Tesla. For example ...