Vanishing Batteries

This post originally appeared in the 7/31/20 edition of Why is This Interesting, an excellent daily newsletter from Noah Brier and Colin Nagy. Check it out.

The electric battery is older than Jesus, but it wasn’t until the early 19th century that the battery as we know it took shape. It started with an Italian chemist attaching bits of metal to frog legs and quickly evolved into more sophisticated types of power cells that didn’t involve dismembered amphibians. Still, the basic principle behind all these batteries was the same. Two metal electrodes, one positive and one negative, trade molecules through a conductive medium called an electrolyte. When the molecules interact with an electrode, it shakes loose some electrons and the battery generates electricity. Within that basic framework there’s a lot of room for innovation. You can mix up the kinds of metals that are used for the electrodes and the composition of the chemical soup that sits between them. For example, new types of battery anodes made with silicon can make batteries last much longer per charge, and using nanoengineered ceramics for a battery’s electrolyte can make them virtually immune to exploding. (This is a big problem if you want to use batteries for large scale industrial applications like ships.)  But the one thing that’s barely changed at all in nearly 200 years is the battery’s form factor—it’s always been a cylinder, a jar, or a pouch.

Today, most batteries you encounter are lithium-ion cells. They’re great because they hold a lot of energy, can be recharged in minutes, are relatively lightweight, and they won’t lose much of their capacity over thousands of cycles. Lithium-ion batteries aren’t without their problems—the reactions in some types of lithium-ion cells can cause them to swell and explode, and some use materials like cobalt that are often mined with child labor. But on the whole they have been an enormous net benefit to society—enough so that the 2019 Nobel Prize in Chemistry was awarded to three scientists who made the lithium-ion battery possible. We put them in our phones, computers, and other small gadgets, and we’re getting pretty good at putting them to use for more heavy-duty applications like driving and storing energy for the electric grid. (NASA’s even using a lithium-ion battery to power its new Mars helicopter that will make the first ever flight on another planet next year.) I don’t think it’s a stretch to say that modern life wouldn’t be possible without the lithium-ion battery. And yet, this electrochemical wunderkind has one glaring shortcoming: it merely provides energy. 

A few years ago I read an article in Smithsonian Magazine about a Swedish engineer named Leif Asp who is trying to build a better battery. Or rather, he’s trying to make the battery disappear. In the article, Asp describes the modern battery as a “structural parasite,” and it’s a phrase that’s stuck with me ever since. From an engineering standpoint, a battery is a whole lot of deadweight. Sure, it provides a critical function—storing and releasing energy—but it doesn’t really contribute anything else to whatever its powering. 

A lot of things in life have dedicated functions; no one faults a lawnmower for its inability to also trim the trees. The problem with batteries is that they tend to eat up a lot of space and weight whenever they’re used. If you pop off the back of your phone, you’ll find that it’s mostly a battery. In a Tesla model S, the battery pack alone accounts for roughly a quarter of the weight of the car. But if Asp has his way, the days of standalone batteries will soon be a thing of the past. Instead, they’ll be replaced by so-called “structural batteries” that provide both power and mechanical support, which can drastically lower the weight and size of most battery-powered machines.

Asp’s research focuses on structural batteries made out of carbon fiber, a versatile material that is several times stronger and stiffer than steel. Carbon fiber is widely used as both a building material and in electronic components, but there’s a tradeoff involved. The types of carbon fiber that are good at conducting electricity aren’t great at bearing heavy loads. His goal is to create a carbon fiber composite that’s the best of both and use it for the electrodes of an ultrastrong lithium-ion battery that could be molded into any conceivable shape.

Asp leads a research consortium called SORCERER that has partnered with a number of large  organizations like Airbus, BAE Systems, and Imperial College London to bring their idea out of the lab and into the real world. He anticipates the first real applications of structural batteries to be hyperniche; for example, they could serve as the body of a Formula E race car. In the future, these structural batteries may also enable more mainstream applications like lithium-ion jumbo jet fuselages or entire office buildings that store excess renewable energy for the grid. 

Generally speaking, there’s an inverse relationship between the maturity of a digital technology and its conspicuousness. It wasn’t that long ago that you had to schedule an appointment to feed punch cards into a computer the size of a room.  Now your smart toaster has a more powerful chip inside of it than those machines ever did—and you don’t even think about it as a computer. Mature digital technologies don’t really “disappear,” they just become embedded in the world around them. But functionally speaking it’s the same thing. Is your smart toaster a computer or a kitchen appliance? The question doesn’t even make sense because it’s both. It was only a matter of time until a similar phase transition happened with energy storage and the battery vanished into the gadget.

(A note on the lede image: That’s Giovanni Aldini, a 19th century Italian physician who used ox heads to generate electricity before frog legs were fashionable.)