Upvote:11
Avios isn't an airline. Presumably you are flying with British Airways or Iberia, which are owned by the same parent company. From BA's list of banned and restricted items:
Please always ensure that you:
[...]
- Don't take any damaged batteries or equipment with you.
By using a damaged lithium ion battery you are endangering yourself, and by taking it on an aircraft, you are endangering your fellow passengers. Even visually undamaged lithium ion batteries can fail catastrophically without warning. The battery casing is intended to protect the cells from damage. Without this protection, they are at a much higher risk of damage, and subsequently, fire.
You should stop using the battery, and dispose of it as soon as possible, according to the laws for electronic waste recycling where you currently are. You should absolutely not travel with this battery on an aircraft.