With a maximum EPA-rated driving range of 326 miles, the Tesla Model Y Long Range has the lowest range in the Tesla model family: the Model 3 Long Range can last 353 miles, while the Model S Long Range can go for up to 405 miles before running out of juice. However, if documents filed in China seen by Australia's The Driven are anything to go by, Tesla is planning to give the popular electric crossover a significant upgrade as the battery technology continually improves.

According to the documents, the new "super long-range" variant registered in China will have 640-km of driving range based on China's CLTC cycle - that's around 397 miles.

This roughly translates to a real-world driving range of 351 miles based on the more stringent EPA cycle used in the US, though the advertised range could be closer to 400 miles. This will put the Model Y miles ahead of the competition when it comes to range. The most efficient Ford Mustang Mach-E California 1 offers a range EPA-rated range of 305 miles, while the RWD Volkswagen ID.4 will last up to 250 miles on a single charge.

It isn't known which battery pack will power the "super long-range" Model Y, but the documents confirm it will have a dual-motor setup with a 137-kW (183-hp) front motor and a 184-kW (246-hp) rear motor.

Combined, this setup will produce 429 miles and 412 lb-ft of torque. It could use Tesla's new 4680 battery cell, which is five times larger than the current 2170 battery cell used in the Model Y allowing for more energy storage.

This won't be the first time the Model Y's range has increased. Last year, a software update increased the range of the Model Y Long Range from 315 to 326 miles. It isn't clear when Tesla will roll out the new extended-range variant, but it could launch later this year to keep Tesla ahead of the competition, and reduce general range anxiety.