Tata is reported to have decided on a site at Bridgwater, Somerset, near to the M5 for its 'gigafactory' rather than going for a rival site in Spain.
The batteries from the factory would be used in electric drive units and battery packs assembled at JLR's plant at the i54, north of Wolverhampton.
The JLR Engine Manufacturing Centre is being renamed the Electric Propulsion Manufacturing Centre, with the switch from internal combustion engines as part of a JLR investment of £15 billion over five years in an all-electric future for its luxury cars.
Tata chairman Natarajan Chandrasekaran is expected to fly to London next week to meet Prime Minister Rishi Sunak and finalise the deal.
The UK's skilled workforce in the automotive industry has helped the UK's bid.
The plant would be one of the most significant automotive investments in the UK since Nissan came to Britain in the 1980s.
Up to 9,000 jobs would be created by the gigafactory at Gravity Business Park.
The Government has wanted to see a major site for electric vehicle battery manufacturing in the UK to secure the future of the car industry.
It is expected that subsidies in the region of hundreds of millions of pounds would be involved in the deal in the form of cash grants, energy subsidies and training and research funding.
Tata also has extensive steel interests in the UK, including the Tata Steel Port Talbot plant in North Wales and the Steelpark at Wednesfield.
The UK currently only has one electric battery plant in operation next to Nissan's Sunderland factory and one just on the drawing board in Northumberland.
Tata has yet to comment officially on the planned deal.
Raj Kandola, director of external affairs at Greater Birmingham Chambers of Commerce, said: “The investment will be very welcome news for the UK, reducing our reliance on imports and providing critical production capability needed to secure a long-term future for electric vehicle production in the country.
“From a West Midlands perspective, our region is home to an extensive automotive supply chain.
“We will need to redouble our efforts to attract a gigafactory to the region.”
Graham Conway, managing director of leading electric vehicle leasing firm Select Car Leasing, said: "This is great news for the British car industry, which has been going through an extremely challenging time in recent years.
"Electric vehicles are the future of motoring and battery production and technology are among the key areas that needs to be addressed to ensure UK drivers can both afford and rely on EVs in their day-to-day lives.
"Not only that, investment on this scale will create jobs at the plant in Somerset and in related industries across the UK.
"Despite the recent dominance of overseas manufacturers, I very much still consider Britain a nation of automotive excellence and moves such as this one by Tata should be welcomed and celebrated."