A second Nikola electric semi-truck caught fire during tests to determine the cause of another blaze

• A Nikola electric semi-truck caught fire during a battery test outside its Phoenix headquarters.
• It comes after another Nikola Tre truck caught alight this week in Tempe, Arizona. 
• Nikola recalled about 209 trucks and suspended sales following two battery fires in June. 

A Nikola electric semi-truck caught fire in a "thermal incident" near its headquarters in Phoenix on Friday.