Apple’s iPhone Air Packs a Battery Breakthrough: Metal Can Design Enables Higher Density & Future Silicon Anodes
SAN FRANCISCO – Apple’s iPhone Air is quietly debuting a important battery technology advancement: a “metal can” battery design, patented by Apple and detailed in US Patent 20210074958A1. This innovation addresses longstanding limitations in smartphone battery shape and swelling, potentially paving the way for increased energy density and the adoption of next-generation silicon anodes.
Unlike traditional pouch cells with flexible plastic casings, the metal can battery encases the entire cell in a rigid metal casing, enhancing strength and durability. According to battery expert Brett Berdichevsky, this design eliminates “pinch points” inherent in Apple’s previously used L-shaped batteries, where swelling can cause failures. “Those are vrey finicky, and this basically makes it bulletproof. You can now build batteries in any two-dimensional shape you want,” Berdichevsky said.
The metal can construction allows Apple to maximize space utilization within the iPhone Air, enabling batteries to conform to available areas around circuit boards. Berdichevsky anticipates widespread adoption of metal can batteries across the smartphone industry, citing the benefits of increased energy storage outweighing the added expense.
The technology is also expected to be crucial for emerging device categories like augmented and virtual reality glasses, where space is at an even greater premium. Berdichevsky noted seeing prototypes in China demonstrating the technology’s application in these smaller form factors, stating, “It’s even more of an energy density advancement as it lets you fit into weird shapes.”
This shift to metal can construction may explain Apple’s current reliance on established lithium-ion chemistry rather than instantly adopting silicon-carbon anodes. “If you’re bringing [a new battery design] online,you kind of go,’You know what? Let’s use yesterday’s chemistry,'” Berdichevsky explained.
Though, the metal can design is poised to unlock the potential of silicon anodes, which can store approximately 50% more energy than traditional graphite anodes.While silicon is prone to swelling, companies like Sila have developed methods to mitigate this issue. The metal can battery provides a more robust framework to manage swelling, allowing for greater performance gains.
“It definitely will help introduce silicon in these kind of devices,” Berdichevsky said. “It lets us push the performance limits more. We’ve always had these trade offs, and we have to manage the swell. You still have to do that, but you can push it a little bit more. It’s pretty revolutionary.”