Ten fire engines and around 70 firefighters tackled a fire at a warehouse on Horn Lane in Greenwich.
Most of a warehouse was damaged by fire. Six people left the building before firefighters arrived. There have been no reports of any injuries.
The Brigade's 999 Control Officers received six calls about the fire.
The Brigade was called at 1120 and the fire was brought under control by 1309. Crews from East Greenwich, Deptford, Poplar, Lee Green and surrounding fire stations attended the scene.
The fire is believed to have been caused by the failure of a lithium battery pack.