RE: Dell XPS 13" 9343 Swollen battery
With a year or just over age system, the failure is premature. At two years old, the battery is near the end of its normal lifespan (generally 18-24 months or 300-500 charge cycles is where lithium ion batteries spike in failure). So it's not going to be easy to argue the problem is a factory defect.
ANY slim lithium battery that is basically encased in a plastic bag can swell. The tech probably works mostly on Dell systems - which is why he said that. He must not work on Mac systems -- where swollen batteries first originated (Apple having adopted slim batteries before anyone else did).
The problem is extremely common in Macbook and Air systems.