The iPhone 17 Air will be officially unveiled in a few weeks. Leaks are already attracting attention. New photos reportedly show the device's battery – and this provides the first clues about Apple's design decisions. Particularly striking is its extremely slim format. With a radically slim chassis, new display size, and special battery design, the model clearly stands out from its predecessors.
The iPhone 17 Air represents a new design philosophy at Apple. Not only will the smartphone be the thinnest iPhone ever, but it also brings with it technical changes that require compromises in battery life. The focus is clearly on the form factor. Initial leaked information reveals how strongly Apple is subordinating itself to the ultra-thin design – even if this impacts the device's endurance.
Images show the iPhone 17 Air battery for the first time
Leaker Majin Bu has published several photos on his website that allegedly show the battery of the upcoming iPhone 17 Air. The images show a component with a steel casing – a design already known from the iPhone 16 Pro.

What's new, however, is the application of this design in a device that's supposed to be even thinner than any iPhone released to date. According to Bu, the battery capacity is approximately 2900 mAh. This figure is consistent with estimates and information from other leakers. Therefore, it's not an outlier, but a value that has been confirmed multiple times.

Ultra-thin housing as the main feature
The most important feature of the iPhone 17 Air is its new, particularly slim casing. Reports suggest that the device will be just 5.55 millimeters thick, making it even thinner than the current iPhone 16 Pro and all previous models in the series. This thin format brings a completely new feel in the hand, but also significantly changes the internals of the device. The casing will not only be extremely slim, but also feature high-quality workmanship. Apple appears to be once again opting for a metal casing, which provides stability without adding unnecessary weight to the device. The battery in the steel casing is part of this concept. It adapts to the compact design, even if this necessitates compromises in capacity.
New display size: 6.6 inches
For the first time, Apple will install a 6.6-inch display on the iPhone 17 Air. This size is new to the iPhone lineup and sits exactly between the previous standard and Pro Max formats. This appeals particularly to users who prefer a large display without a bulky device. Despite the larger screen diagonal, the casing remains slim and lightweight thanks to its low thickness.
Battery life: weak point despite iOS 26
The decision to opt for an extremely thin design has a direct impact on battery life. With a capacity of around 2900 mAh, the battery is below the level of other models in the iPhone 17 series. Despite software improvements—for example, new features in iOS 26 such as Adaptive Power Mode—the iPhone 17 Air is expected to be the model with the shortest battery life. Apple is apparently relying on intelligent control of energy consumption to compensate for the limited capacity. This should be sufficient for normal daily use in many cases. However, those who spend a lot of time with graphics-intensive apps or streaming will need to reach for the charging cable more often.
Design wins, battery loses: The iPhone 17 Air's balance sheet
The iPhone 17 Air combines a new 6.6-inch display with an extremely thin body, measuring just 5.55 mm. It will be the slimmest iPhone yet and features a steel-case battery design. The battery capacity is approximately 2900 mAh, which is rather low compared to other models. While iOS 26 brings new features to increase efficiency, it can't completely overcome physical limitations. Overall, the iPhone 17 Air offers an uncompromising design for those who value form, lightness, and display size—with the knowledge that compromises will be necessary in terms of battery life. (Image: MajinBuOfficial)
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