Batteries for the top-rung 62kWh version of the Leaf electric hatchback are currently produced in the USA and imported to the UK, while lower-capacity 40kWh units are built at Sunderland by Chinese firm Envision Group, which will also handle production of the larger units.
Shifting all battery production to the UK will mean Nissan avoids incurring tariffs on the 70% of Leaf models built for export under the terms of the new trade deal, which states that at least 55% of a vehicle's material value must come from the UK or EU to avoid penalties.
Speaking to the BBC, Nissan chief operating officer Ashwani Gupta said: "The Brexit deal is positive for Nissan. Being the largest auto maker in the UK, we are taking this opportunity to redefine auto-making in the UK."
"It has created a competitive environment for Sunderland, not just inside the UK but outside as well. We've decided to localise the manufacture of the 62kWh battery in Sunderland so that all our products qualify [for tariff-free export to the EU].
"We are committed to Sunderland for the long term under the business conditions that have been agreed."
Last week, Nissan UK managing director Andrew Humberstone told dealers nationwide that the Brexit deal "finally gives us some certainty and enables us to plan for the future success of our collective operations across the region”.
Nissan had said that it would be unable to commit to the Sunderland factory in the event of a no-deal Brexit, with the possibility of heavy tariffs making exports financially unviable.