Although the slim design of the iPhone Air is stunning and the miniaturization engineering of its motherboard is also excellent, according to Gene Berdichevsky, co-founder and CEO of battery materials manufacturer Sila, the real technological breakthrough may be hidden within the aluminum and glass body.
Berdichevsky said in an interview: "The battery of the new iPhone is amazing. It adopts a completely unrestricted two-dimensional shape - you can tell by its shape, it is very shocking." He added: "I just came back from Asia and had the opportunity to see some of these cells. This is a revolutionary battery technology."
Berdichevsky has extensive research on battery technology. He was the seventh employee of Tesla and led the engineering work of the first-generation Roadster battery, which laid the template for Tesla's later battery system. Sila, a company he currently leads, is producing silicon anode materials for consumer electronics and upcoming electric vehicles.
The unique notch design of the iPhone Air benefits from Apple’s patented metal can battery technology. As the name suggests, this technology wraps the entire battery cell in a metal casing, adding strength and durability. Currently, soft-pack batteries commonly used in consumer electronics are wrapped in cheap and expandable plastic casings.
Apple has actually used L-shaped batteries in iPhones for many years, but all lithium-ion batteries expand, and the inner corners of the L-shape become pressure points and are very fragile. In this regard, Berdichevsky said: "These L-shaped designs are actually difficult to handle, and the metal casing makes the battery almost indestructible. Now you can make batteries in almost any two-dimensional shape on demand."
The metal case battery allows Apple to make full use of the limited space inside the iPhone Air. "They can make the battery very close to the edge of the fuselage," he said. This means that the battery can cleverly fill in any irregular gaps left behind by the circuit board.
Berdichevsky predicts that despite the higher cost, most mobile phones will switch to such metal can batteries in the future because the extra energy is well worth it. He also pointed out that this technology will be even more critical for smaller devices such as AR and VR. "Because it can adapt to strange shapes, the energy density increase is even more obvious."
The extremely complex new battery structure is one of the reasons why Apple has not introduced silicon-based silicon-carbon anodes in its lithium-ion batteries. "If you're introducing a new battery architecture, you tend to think, 'We might as well start with the existing chemistry,'" explains Berdichevsky.
However, he believes that the popularity of metal can batteries is expected to pave the way for the large-scale application of silicon anodes in the future. Pure silicon anodes have about 50% higher energy density than traditional graphite anodes, but the material itself is prone to expansion. Although companies like Sila have developed relevant management methods, further optimization is still needed at the battery cell level.
"This technology really facilitates the introduction of silicon anodes, allowing us to further push the performance envelope. Previously, we have been limited by the trade-offs caused by expansion. This time it will be more flexible in terms of management. This is a real revolution."