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On Batteries and Innovation

Despite reports of breakthroughs in battery technology, the hard problems of battery innovation remain hard.

Lately there’s been a spate of articles about breakthroughs in battery technology. Better batteries are important, for any of a number of reasons: electric cars, smoothing out variations in the power grid, cell phones, and laptops that don’t need to be recharged daily.

All of these nascent technologies are important, but some of them leave me cold, and in a way that seems important. It’s relatively easy to invent new technology, but a lot harder to bring it to market. I’m starting to understand why. The problem isn’t just commercializing a new technology — it’s everything that surrounds that new technology.

Take an article like Battery Breakthrough Offers 30 Times More Power, Charges 1,000 Times Faster. For the purposes of argument, let’s assume that the technology works; I’m not an expert on the chemistry of batteries, so I have no reason to believe that it doesn’t. But then let’s take a step back and think about what a battery does. When you discharge a battery, you’re using a chemical reaction to create electrical current (which is moving electrical charge). When you charge a battery, you’re reversing that reaction: you’re essentially taking the current and putting that back in the battery.

So, if a battery is going to store 30 times as much power and charge 1,000 times faster, that means that the wires that connect to it need to carry 30,000 times more current. (Let’s ignore questions like “faster than what?,” but most batteries I’ve seen take between two and eight hours to charge.) It’s reasonable to assume that a new battery technology might be able to store electrical charge more efficiently, but the charging process is already surprisingly efficient: on the order of 50% to 80%, but possibly much higher for a lithium battery. So improved charging efficiency isn’t going to help much — if charging a battery is already 50% efficient, making it 100% efficient only improves things by a factor of two. How big are the wires for an automobile battery charger? Can you imagine wires big enough to handle thousands of times as much current? I don’t think Apple is going to make any thin, sexy laptops if the charging cable is made from 0000 gauge wire (roughly 1/2 inch thick, capacity of 195 amps at 60 degrees C). And I certainly don’t think, as the article claims, that I’ll be able to jump-start my car with the battery in my cell phone — I don’t have any idea how I’d connect a wire with the current-handling capacity of a jumper cable to any cell phone I’d be willing to carry, nor do I want a phone that turns into an incendiary firebrick when it’s charged, even if I only need to charge it once a year.

Here’s an older article that’s much more in touch with reality: Battery breakthrough could bring electric cars to all. The claims are much more limited: these new batteries deliver 2.5 times as much energy with roughly the same weight as current batteries. But more than that, look at the picture. You don’t get a sense of the scale, but notice that the tabs extending from the batteries (no doubt the electrical contacts) are relatively large in relation to the battery’s body, certainly larger in relation to the battery’s size than the terminal posts on a typical auto battery. And even more, the terminals are flat, which maximizes surface area, which maximizes both heat dissipation (a big issue at high current), and surface area (to transfer power more efficiently). That’s what I like to see, and that’s what makes me think that this is a breakthrough that, while less dramatic, isn’t being over-hyped by irresponsible reporting.

I’m not saying that the problems presented by ultra-high capacity batteries aren’t solvable. I’m sure that the researchers are well aware of the issues. Sadly, I’m not so surprised that the reporters who wrote about the research didn’t understand the issues, resulting in some rather naive claims about what the technology could accomplish. I can imagine that there are ways to distribute current within the batteries that might solve some of the current carrying issues. (For example, high terminal voltages with an internal voltage divider network that distributes current to a huge number of cells). As we used to say in college, “That’s an engineering problem” — but it’s an engineering problem that’s certainly not trivial.

This argument isn’t intended to dump cold water on battery research, nor is it really to complain about the press coverage (though it was relatively uninformed, to put it politely, about the realities of moving electrical charge around). There’s a bigger point here: innovation is hard. It’s not just about the conceptual breakthrough that lets you put 30 times as much charge in one battery, or 64 times as many power-hungry CPUs on one Google Glass frame. It’s about everything else that surrounds the breakthrough: supplying power, dissipating heat, connecting wires, and more. The cost of innovation has plummeted in recent years, and that will allow innovators to focus more on the hard problems and less on peripheral issues like design and manufacturing. But the hard problems remain hard.

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  • David Fuchs

    In the short term we will have batteries that have 4 times the storage capacity. This will happen in the next 1-3 years, due to graphene silicon micro flakes that are now being bulk produced as an additive for Li-ion batteries.

    http://cleantechnica.com/2013/04/22/graphene-silicon-nanoplatelets-increase-lithium-ion-battery-capacity-4-fold/

    The theoretical max for this technology is about 10 times the current storage capacity of Li-ion.

    The short term result of this is cars like the Tesla with a 1,200 mile range, the fiat 500e will clock in with a 240 mile range, and the Volt … well, who really cares about that one.

    The batteries they are talking about in the article are years (reads decade(s)) off due to the need to manufacture such small structures for them to function. If they are produced in the next 3-5 years they will be extremely expensive. They will be used in a very limited number of devices. What do expect from a university press release?

    • Bruce

      Interesting article, raising points I haven’t thought about. Regarding needing larger wires – not necessarily so. Faster charging a battery requires increased power, not necessarily increased current (which would require larger wires). Power = voltage x current; so you could also get increased power by upping the voltage, which would not require larger copper (but may require better insulation).
      On the point of batteries being a chemical reaction, this isn’t always true in some of the newer, experimental technologies. Some are trying to use the “super capacitor” model, which basically is like a super-efficient capacitor which stores electrical charge, not a change in the chemical make-up of the battery.

  • Dweeberly

    Your points are well taken. I would say that capacity is generally more important that charge time, assuming it’s “firebrick” safe. There are ways to produce a faster charge with smaller wire gauges, but clearly there are limits to how much power you can push through a (non-super) conductor. I think the actual barriers are more of the “economies of scale” and “resistance to change” type. The current trend to produce ever thinner phones/tablets/laptops would welcome a battery with twice the capacity at the same size (or the same capacity at half the size) even at a higher price cost. Innovation is hard and generally takes place in smaller shops where the benefits more easily outweigh the risks. I.E. at CEO making millions a year isn’t going to take chances on new tech, while the guy who’s got little to lose will. Little guys don’t get much press coverage. I suspect there is quite a bit of this sort of “invisible” innovation occurring.

  • Mark

    Lets talk about your “Battery Breakthrough Offers 30 Times More Power, Charges 1,000 Times Faster”. My samsung’s battery capacity is 5.5Wh (3.7V @ 1.5Ah). Lets say its capacity is 166Wh. At 3.7V, thats 45Ah. If you charge it in 3 hour, that’ll be 15A through your cable. Thats about as much as your AC. But it’ll hold for two months, and if its 90% efficiency and you’re not using the device that time, theres no reason for it to heat… c’mon, do the math