Four fire engines and around 25 firefighters were called to a fire at a shop with flats above on Maxwell Road in Northwood.
Part of the ground-floor shop was damaged by fire. One person left a first-floor flat above the shop before the Brigade arrived. There were no reports of any injuries.
The Brigade’s Fire Investigators believe the fire was accidental and involved lithium-ion batteries for a golf buggy.
A London Fire Brigade spokesperson said: “Batteries can present a fire risk if they’re over-charged, short circuited, submerged in water or damaged, so it’s really important to protect them against being damaged and charge them safely.
"Unplug devices once they have finished charging and always make sure you use the right charger for your device.”
The Brigade was called at 0003 and the fire was under control by 0204. Fire crews from Ruislip, Harrow and Hertfordshire Fire and Rescue Service attended the scene.