Four fire engines and around 25 firefighters were called to a fire at an industrial estate on Brent Crescent in Park Royal.
A storage room on the ground floor of a two-storey industrial unit was destroyed by fire. Firefighters removed around 100 large lithium-ion batteries to open air. A 25 metre cordon was put in place as a precaution whilst crews worked to make the scene safe. There were no reports of any injuries.
The Brigade's Fire Investigators believe the fire was caused by a water leak which created a short circuit across several batteries in the storage room.
A London Fire Brigade spokesperson said: "Batteries can present a fire risk when over-charged, short-circuited, submerged in water or if they are damaged.
"Avoid storing, using or charging batteries at very high or low temperatures and make sure they are properly protected when stored. It's really important to charge them safely too."
The Brigade was called at 1149 and the fire was under control by 1452. Fire crews from Park Royal, Wembley and Ealing fire stations attended the scene.