The most exciting Apple announcement this week wasn't a $10,000 smartwatch or a new, gold-colored MacBook. It was a battery technology that could have major implications for how long all future Apple products last between charges—including your next iPhone.

Apple's battery breakthrough is already paying dividends in Apple's super-slender MacBook. In order to achieve that 13.1 mm silhouette—and still deliver reasonable battery life while powering a 12-inch Retina display—the company's engineers had to develop something entirely new. What they came up with is a terraced battery cell, a unique design that adds 35 percent more battery capacity than would otherwise be achievable.

"It might seem like a low level innovation, but it's an incredibly clever design," Jeff Chamberlain, executive director of the Joint Center for Energy Storage Research, told WIRED. In fact, it's a whole new way of thinking about batteries.

Rethinking the Battery

A typical lithium ion battery "pouch" type cell comprises layers of a thin sheet of aluminum or copper, coatings of a specialized material that can absorb lithium ions, and layers of plastic. Each of these layers is mere microns thick.

What Apple has figured out, according to a patent filed back in early 2012, is how to fit these stacked electrode sheets into any size cell they choose. These different-sized cells can then be stacked on top of one another, allowing its engineers to pack as much battery as possible into any given space.

In order to assemble the terraced battery cells in the MacBook, Apple says it used high speed cameras to take photos of the casing and the battery. This process documents the minute variations in each that occur during real-world production, so that Apple can fit the batteries inside each individual casing with an unprecedented degree of precision.

Apple also—according to what it said during its Monday keynote—tweaked the chemical formula inside the cells. That didn't have any bearing on the unique battery shape, but by altering the composition, Apple could eke a little bit more efficiency over previous MacBook batteries.

Apple lists the MacBook has achieving up to nine hours of battery life. That may sounds relatively paltry—the 13-inch Air gets 12-hours of battery power—until you consider that it has to push power to a Retina display's huge number of pixels. The 13-inch MacBook Pro with Retina gets 10 hours of battery life, and the 15-inch model gets eight hours. In a form factor that's 1.5 pounds lighter and .2 inches thinner (at its thickest point), the MacBook lasts comparably long. That's impressive, even when you also consider its power-sipping Core M processor.

An Adaptable Innovation

What's even more exciting, though, is that while the MacBook is the first consumer product to use this new battery technology, we're sure to see it applied to other iDevices. Apple's tick-tock upgrade cycle for the iPhone normally leaves minimal hardware changes for the "tock" models (the "S" versions, like the iPhone 4s and 5S). But with the iPhone 6 and 6 Plus's contoured exterior, it's not a stretch that this year's S model could include the new battery tech. The beefed up battery design could also easily make its way into the iPad line, and into future MacBook Airs or MacBook Pros (both of which only saw minimal updates during Monday's event).

Even if we don't see this tech applied to new products immediately, we will undoubtedly see it at some point. iFixit's Kyle Wiens says that one of the most important results of this battery innovation is its implications on product design across a whole range of devices.

"It frees the industrial designers to be able to design what they want, and then fit the battery in after the fact, rather than creating the design around the battery," Wiens told WIRED. Until now, hardware designers have been a slave to the battery size required of a particular device, and forced to build a rectangle, or rounded rectangle, around that.

So, naturally, Apple engineered a new design that frees Jony Ive and team to let their imaginations run wild with possibilities. In addition to the rectangular layers we see in the MacBook, this terraced battery could also theoretically work in circular, triangular, and other shaped spaces. That's not to say we're ever going to see a trapezoidal iPad. But at the very least, it enables unconventional thought, like contouring the battery around the spot where the Macbook's rubberized black feet attach to the notebook (which Apple did).

The redesigned battery also doesn't sacrifice overall longevity; the new MacBook will survive around 1,000 charges, just like all other Apple laptops. The one caveat would be that this is a proprietary battery, so it will be difficult, if not impossible, to replace yourself, should it wimp out before you're ready to buy a new notebook. Then again, it's not like Apple makes it easy to replace your battery anyway.

Eventually, some crazy new innovation in mobile energy storage will come along and end all our lithium ion woes. That could be a long way off, though. And the fact that Apple's not content to sit around waiting for it could end up giving its devices—and you—more battery life relief than you could have imagined.