Samsung has confirmed that overheating batteries in its Galaxy Note 7 smartphones caused them to catch fire. In September last year, the tech giant recalled more than 2.5 million devices because of the defective lithium batteries. They have confirmed that neither software or hardware other than the batteries were to blame, and that the batteries were either made the wrong size for the phone, or had other production flaws. The recall is thought to have cost the South Korean firm AED15 billion.