A woman looks at the screen of her mobile phone in front of an Apple logo outside its store in downtown Shanghai September 10, 2013.
A woman looks at the screen of her mobile phone in front of an Apple logo outside its store in downtown Shanghai September 10, 2013. Reuters

Apple is set to roll out two iPhone models in 2014. The company will have a 4.7-inch screen and the other will have a 5.5-inch display, as claimed by earlier reports.

Notably, the 5.5-inch iPhone will be called "iPad Air." Business Times (Taiwan) reported Apple's larger and much awaited 5.5-inch iPhone 6 model may be delayed until 2015.

Evidently, Apple is caught up in a production problem with the units' battery requirement. With regard to iPhone 6 models, Apple needs relatively thinner batteries for the 5.5-inch iPhone when compared to its devices from the past to fit inside the smartphone's redesigned case, and the suppliers that Apple had tie-up and are presently not able to meet the very high demand from the smartphone maker.

The publication said the 5.5-inch iPhone 6 should require a 2 mm thick battery cell, which translates to the unit being one-third thinner than the batteries from its competitors, which is normally 2.8 mm or 2.9 mm thick.

Hence it is obvious iPhone 6 will be a way thinner than Apple's flagship iPhone 5S. The rumored iPhone 6 is set to have a profile between 6.5 mm and 7.0 mm, compared to iPhone 5S, which is 7.6 mm thick, according to BGR.

Although the battery unit expectation is smaller than the previous models, this battery unit is touted to pack a 50 percent to 70 percent extra watt-hours than iPhone 5S. Also, other reports suggested the perceived delay in the 5.5-inch iPhone with supply chain sources misconstrued prototype testing to be the actual product.

The new report from Taiwan cannot be confirmed because Apple has never confirmed the production of 5.5-inch iPhone 6 or a promised launch date in 2014. Such rumors suggested Apple's trouble with manufacturing issues with a mobile component ahead of a new iPhone launch is not uncommon.

Even though the delay is expected for 5.5-inch iPhone, the smaller sized 4.7-inch iPhone 6 would be rolling out in September, which is in line with Apple's regular launch time range.

When it comes to apps for 4.7-inch iPhone, the latest retina screen apps could be more spaciously arranged and would add an additional row full of icons in the device's home screen. The iOS app developers might have to keep the new screen size in mind, after all Apple doesn't change its screen size quite often like Samsung.