Four fire engines and around 25 firefighters tackled a house fire on Churchill Avenue in Harrow.
Half of the ground floor of a semi-detached house was damaged by fire. There were no reports of any injuries.
A resident was alerted to the fire by the smell of burning. They then saw smoke coming from around a door on the ground floor and on investigation they discovered a fire in a rear bedroom.
The Brigade’s 999 Control Officers took 13 calls to the blaze.
The fire is believed to have been caused by the failure of a lithium-ion battery for a mobile phone that was on charge and left on top of bedding.
A London Fire Brigade spokesperson said: “On arrival crews were faced with a well-developed fire with smoke coming from the rear of the property.
“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.
"Electrical devices should always be charged on hard flat surfaces where heat can dissipate, and you should also make sure you unplug your charger once it’s finished charging.”
The Brigade was called at 1044 and the fire was under control by 1220. Fire crews from Harrow, Stanmore and Wembley fire stations attended the scene.