Rumors of a longer-range battery for the 2016 Nissan Leaf have been percolating for a while now.

Nissan has steadfastly declined to answer questions about the next model year of the world's most successful electric car, but at least one report now suggests that a revised Leaf is imminent.

DON'T MISS: Nissan Leaf With 250-Mile Range: Ghosn Shows R&D Car, Video At Annual Meeting

According to industry trade journal Automotive News, a longer-range 2016 Leaf could be launched as soon as next month.

Note that this is not the all-new second-generation Nissan Leaf, expected as a 2017 or 2018 model, but a running change to the current model that's been in production since late 2010.

2015 Nissan Leaf

2015 Nissan Leaf

The updated battery, according to Automotive News, will have an energy capacity of 30 kilowatt-hours--up from the 2015's 24 kWh--but fit within the same pack housing.

The report didn't specify whether this would be the new standard battery for the Leaf or an extra-cost option.

It also didn't say whether this would be a global change for all Leafs, not only those manufactured in the U.S. but also Leafs made in Japan and the U.K.

ALSO SEE: 2017 Nissan Leaf: What We Know So Far About New Electric Car

A 25-percent increase in energy capacity would be expected to boost rated range, now 84 miles, to something like 105 miles.

But an unnamed source in the report suggests that Nissan expects to get "an EPA-rated range of about 125 miles on a full charge"--though real-world range will be "closer to 105 to 110 miles," it says.

It's possible that updates to the motor, the power electronics, the regenerative braking, and/or the powertrain control software could eke out a higher range rating than the capacity boost alone would provide.

2015 Nissan Leaf 4-door HB SL Dashboard

2015 Nissan Leaf 4-door HB SL Dashboard

Indeed, modifications to those systems had previously boosted the range of the 2013 model to 84 miles (on a full charge) against the 73-mile rating of the 2011 and 2012 models.

The Chevrolet Volt range-extended electric car, too, has now seen three capacity increases in its battery energy capacity.

The 2011-2012 cars had 16 kWh, the 2013-2014 cars rose to 16.5 kWh, the 2015 had 17.1 kWh, and the all-new second-generation 2016 Volt jumps to 18.4 kWh.

MORE: Should I Buy A Used Nissan Leaf (Or Another Electric Car)?

Automotive News notes that U.S. sales of Nissan Leafs will be essentially flat this year, due to a combination of Georgia's electric-car tax credit ending, low gasoline prices, and a flood of three-year-old Leafs entering the used-car market.

The comments from the Nissan source came at the company's annual meeting, during which CEO Carlos Ghosn showed a video of a Leaf development prototype with a range of more than 300 miles.

Nissan's prior product chief, Andy Palmer (now CEO of Aston-Martin), told Green Car Reports last year that the next-generation Leaf would offer a choice of two or three battery packs with capacities as high as 150 miles.

Nissan Leaf 'Advanced R&D Electric Vehicle' shown at company annual meeting, Yokohama, Jun 2015

Nissan Leaf 'Advanced R&D Electric Vehicle' shown at company annual meeting, Yokohama, Jun 2015

Industry observers now expect the next Leaf to offer at least one version with a range rating of around 200 miles.

That would permit the Leaf to counter the 2017 Chevrolet Bolt EV--which GM CEO Mary Barra said will have a 200-mile range, at a price of $37,500--that is to launch late next year.

The Leaf, built on compact-car underpinnings, is a larger five-door hatchback than the Bolt EV, which uses elements of an architecture shared with the Chevy Sonic subcompact.


Follow GreenCarReports on Facebook, Twitter, and Google+.