The iPhone Air’s thin design is certainly eye-catching, and the engineering behind its miniaturized logic board is impressive. However, according to Gene Berdichevsky, co-founder and CEO of battery materials manufacturer Sila, the real breakthrough may be found elsewhere inside the device.
Berdichevsky states that the battery in the new iPhone is pretty remarkable. He highlights its completely arbitrary, two-dimensional shape as amazing. Having recently seen the cells in Asia, he called it a revolutionary piece of battery tech.
Berdichevsky has significant expertise in this field. As Tesla’s seventh employee, he led the engineering on the original Roadster’s battery, which set the template for later Tesla models. He now leads Sila, a company producing silicon anode materials for consumer electronics and, soon, electric vehicles.
The iPhone Air’s notched design is enabled by a patented Apple technology called a metal can battery. This name refers to the metal casing that surrounds the entire cell, adding strength and durability. This differs from the pouch cells common in consumer electronics, which use a soft, cheap plastic casing that allows for swelling.
While Apple has used L-shaped batteries for years, the interior corner of the L can become a pinch point when the battery swells. The metal can design solves this problem, making the battery bulletproof and allowing for construction in any two-dimensional shape.
This technology allows Apple to maximize the use of space within the iPhone Air, enabling the battery to fit very close to the edges and weave into any free area after the circuit boards are positioned. Berdichevsky believes most phones will eventually adopt metal can batteries despite the added cost, as the extra energy storage will be worth it.
He also notes this will be very key for smaller devices like AR and VR glasses, where fitting into weird shapes provides an even greater energy density improvement. He saw several such prototypes while in China.
The complexity of this new battery design is likely why Apple has not yet switched from carbon anodes to silicon-carbon versions. When introducing a new design, it is common to use yesterday’s proven chemistry first.
However, the shift to metal can construction could pave the way for silicon anodes in the future. Pure silicon anodes can store about fifty percent more energy than traditional graphite anodes, but the material swells considerably. While companies like Sila have developed ways to manage this swelling within the material itself, it still must be accounted for in the cell design.
Berdichevsky concludes that the metal can technology will definitely help introduce silicon into these devices. It allows engineers to push performance limits further by providing a more robust structure to manage the necessary trade-offs and swelling, calling it a pretty revolutionary development.