The iPhone 8 will likely have wireless charging — but that could make it prone to overheating

Kif Leswing, Business Insider

A fan's concept drawing of the iPhone 8, based on current rumors.YouTube/ConceptsiPhone

All three iPhones expected to launch later this year will have wireless charging, according to a new forecast by KGI Securities analyst Ming-Chi Kuo.

Apple is expected to release three new iPhones next fall — one premium model with a better screen using "OLED" technology, and two more iterative improvements to the current iPhone 7 and iPhone 7 Plus. 

All three will have glass casing and wireless charging, according to Kuo's note seen by Business Insider. 

Apple may be concerned that the new iPhones may overheat more than older phones, according to the research. Glass casing and wireless charging are "unfavorable to thermal system operation," says Kuo. 

From the note: 

Adoption of glass casing & wireless charging unfavorable to thermal system operation for three new 2017F iPhone models; bigger impact on OLED model. The thermal system becomes less efficient with glass casing, as compared to metal casing used previously. Furthermore, wireless charging increases handset temperature. While we don’t expect general users to notice any difference, lamination of an additional graphite sheet is needed for better thermal control and, thus, steady operation; this is because FPCB is replaced with film, which is more sensitive to temperature change of the 3D touch sensor in OLED iPhone.

Kuo notes that the new, premium phone will have more overheating issues than the other two. Apple might have to add an insulating graphite sheet to prevent it from malfunctioning. That sheet, and other tech changes, could raise the price that Apple pays for the 3D Touch module for the new OLED iPhone as much as 50%.

The research note distributed to clients focuses on some of the parts that Apple buys from suppliers to make its screens and features like 3D touch work.

"We believe OLED iPhone will provide a better 3D touch user experience on the back of the new design," Kuo writes. Because of this, Kuo advises clients to expect shares of Apple suppliers General Interface Solution and TPK Holding Company to outperform.

The cost of cutting edge parts may be one reason why it's rumored that the premium OLED iPhone could cost over $1000, according to a recent report.

Here's what we're expecting from the iPhone 8:

A 5.8-inch OLED screen.Wireless charging. Sides made of "forged stainless steel" and a back made of glass.The home button and fingerprint sensor built into and under an edge-to-edge screen.A double lens camera, like on the iPhone 7 Plus.New 3D-sensing technology enabling "some form of facial/gesture recognition."A launch date in the fall — likely in September, as usual.