Taiwanese battery maker Prologium has a lithium ceramic battery that bends, folds, cuts, and doesn’t explode. SemiAccurate takes a look at the interesting bits surrounding their solid state electrolyte batteries.
First a little background, I have been writing about why batteries explode for over a decade, the first one I recall was in February of 2004 shortly after The Inquirer posted the first pictures of a laptop in mid-kaboom. Sorry no links because of this and this.
Over the years I have seen when batteries are a real problem, a random occurrence, or a grassroots smear job kept alive by the drumbeats of a competitor or public ignorance. We have seen all of these things and more in the past decade plus and a few more, thing like the Samsung Note 7s going kaboom are pretty run of the mill, and in our opinion is being blown out of proportion.
Bent, cut, punctured, and generally molested batteries
Getting back to the Prologium and their lithium ceramic solid state electrolyte battery, it could change the game. As you can see above, you can bend it, fold it, cut it, submerge it, and poke holes through it without things going into thermal runaway. That is the fancy term for kaboom, essentially when the battery shorts internally it uses its own energy to light various internal bits on fire. One common way of preventing these runaways is to internally fuse a battery so it is compartmentalized and the energy from a short is both contained and too low to start a chain reaction.
Unfortunately the biggest trend in energy density gains over the past few years isn’t better materials or chemistry, it is just packing more in. This tends to be done by making the non-current bearing bits thinner and smaller, something that includes the cases, fuses, and other protective bits. Limits are routinely pushed, that is called engineering. When things go wrong however there is less to stop the runaway and less to contain it when the reaction feeds itself.
The electrolyte is a common problem component in most cases plus lithium is a bit reactive with water. If you have ever picked up a chunk of lithium metal, well if your fingerprints have grown back by now the lesson was learned. If you look up the energy density of modern batteries, they tend to compare favorably with many types of explosives. Back to the story now, really.
So Prologium makes a battery with a solid state electrolyte and they call the whole thing LCB or Lithium Ceramic Battery. Since the electrolyte is ceramic it doesn’t burn well, try lighting your toilet bowl on fire if you don’t believe me. Unlike a toilet bowl however the ceramic used in LCBs is flexible, very flexible but there are limits. As you can see above though, even a severely damaged Prologium cell will put out energy and keep working. It won’t explode either, ceramics don’t burn because they are by definition oxidized fully and in a very low energy state.
Flexible batteries can roll to fit a stylus
So we have a battery that is thin, somewhat flexible, damage resistant, and is almost impossible to set on fire. Of these thin is probably the most important, Prologium claims their cell can be as thin as .38mm per cell and comes in three flavors, FLCB, PLCB, and ELCB. Those are flexible, packaged aka in aluminum foil and can be multi-layer, and high energy, The names pretty much explain the differences but all are based on solid-state electrolyte chemistry.
Things get more interesting when you look at how thin LCBs can be, a key feature in modern fashion electronics like phones. The .38mm per cell is a nice number but it gets better because you can print directly on the cell without a barrier layer. Barrier layers are usually pretty thin but when you are talking about phones and such in the notably sub-9mm z-height range, it matters. More importantly what percentage of .38mm would a ‘thin’ barrier add? Believe me when I say it matters to device manufacturers.
Print circuits directly on a cell
As you can see above with the reference designs, printing on the cell means printing circuitry on the cell itself. Credit cards with one time key generators and RSA-esque security cards are one application but Prologium had quite a few others. The antenna card can put a wireless charging subsystem on the battery itself, quite the neat trick, while the bluetooth cards adds an antenna for that protocol. The logic cell is probably the most interesting, the possibilities abound. All of this you can do with a normal lithium cell but not without adding barriers aka z-height and hopefully a case in case of fire, see what we did there? Ha!
Prologium had a few neat concepts at their booth during Computex, the belt above, an insole foot warmer device, and a rolled battery thin enough to fit in a pencil-thin stylus. Bend radius matters quite a bit in some applications, pens being one of them. Not going boom matters a bit more especially when the heat source is literally tied to the bottom of your foot.
From there the possibilities abound, bullet proof vests, belts acting as a smart wallet and ID, smart clothing, and the rest. Most of these things could be done with conventional types of cells but the flexibility and safety were enough of a concern to keep things in niches. If Prologium is delivering what they say they are, and it has better power densities than the Galaxy S6 and iPhone 6 batteries (Note: these claims were from pre-GS7 and iPhone 7 launch times), I think they have a winner on their hands. Even if it isn’t as good in some areas, as today’s headlines show, fireproof batteries are a good thing.S|A