We've talked before about integrating significant amounts of analog functionality on to a silicon chip. That part is getting easier. In medical implant applications, this sort of integration is great, but what about the power source? It turns out that can be integrated, too.
Harvard University's Wyss Institute for Biologically Inspired Engineering recently described a method for making batteries with 3D printing. (The institute is an alliance among Harvard's Schools of Medicine, Engineering, and Arts & Sciences.) These are lithium-ion chemistry devices that can be as small as a few hundred micrometers on a side.
The proof-of-concept devices were fabricated by two teams of researchers — one at Harvard and one at the University of Illinois at Urbana-Champaign. They used a 30-micron nozzle operating at 105 psi and standard 3D printing techniques to print precisely interlaced electrodes. Since printing just one pair of interwoven electrodes would not create a battery with sufficient capacity, the researchers stacked one cell on top of another. They could do this because the extruded material would harden almost immediately. The stacking technique gave them the capacity they needed.
A battery requires two separate metallic compounds — one to make an anode (the cell's negative terminal) and one to make a cathode. Various metal pairs will work electrochemically. For anodes, lithium nickel cobalt aluminum oxide and lithium titanate will work. For cathodes, lithium iron phosphate, lithium manganese oxide, and lithium nickel manganese cobalt oxide will work. These were extruded on to two tiny gold combs.
The researchers put the comb assembly into a container and added an electrolyte solution. Voila — a battery.
This Wyss Institute video (running as twice the actual speed) shows a battery being made.
Even using this stacking method, the capacity is pretty low — on the order of tens of microamp-hours — but it's sufficient for some medical implants. It's important to keep in mind that for any design work on ICs for medical implant devices, the IC must be very low power.
Do you have any applications where a battery like this would be useful? Have you used a method like this already?
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Hello Brad, great article!
We're still heading for this application but a small battery will always be welcome to mobile devices, especially as reported for medical equipment.
As soon as it will be an even more accessible! This will expand new ideas …
@Brad, thanks for the post. I knew we could print many products using 3D technology but never knew we could print batteries using 3D technology. Its very exciting to know that so many things can be printed using 3D technology.
With the right materials, the battery can be the case for the product! There are so many possibilities.
There are energy harvesting applications where a small battery to “cache” the energy before using would be a good idea. It would be interesting to see how this compares to a supercapacitor, though.
Still, with the ultra low power many MCUs are requireing these days, the ability to print a battery just might be a really cool way of creating non-volatility in an IC. Bond in the chip, print on a battery, then finish the encapsulation.
Lots of possibilities here.
@Steve – yep, that's the idea. I predict that this will see widespread use over the next few years.
@Rich – yep, it is rechargeable. The chemistry that I cited above allows for recharging. I expect this can be fabricated far smaller than a super cap, tho' certainly the super cap would have far higher energy capability. But this is for cases where you don't need that much energy.
Hi Brad,
When I was at NASA Ames a couple of months ago, I visited the “Spaceshop” lab with the only 3D printer that will be used on the International Space Station in 2014 to fabricate some parts replacements while up there miles above the Earth. So, 3D printing will revolutionize so many designs I expect. Engineer's creative imaginations will surely find uses we have never even conceived of yet!
When I was at NASA Ames a couple of months ago, I visited the “Spaceshop” lab with the only 3D printer that will be used on the International Space Station in 2014 to fabricate some parts replacements while up there miles above the Earth.
@Steve, Wow you got an opportunity to see the 3D printer which will be used in International space station. Can you give more details about the printer ? What material does it use for printing.
@SunitaT–The Made in Space 3D Printer is built specifically to handle the environmental challenges of space and uses extrusion additive manufacturing, which builds objects layer by layer out of polymers and other materials.
The printer will work in zero-gravity and could manufacture parts that need replacement that are common tools or something that could be critical to life support. Remember, if there is a failure in space, you can't wait until the Russians send up a shuttle craft. If the part is not on board, then it could be a life-threatening situation.
Depending on what material they print with, they could temper a metal printed device in the Drop Physics Module (DPM) to solidify the part into something really useful. The DPM was built partially by Loral back in 1990s and it uses acoustic levitation method do center the experiment in the middle. Heat and cold can be added to see how materials are affected.
@RedDerek—sounds interesting, I have to look up that DPM details
@Steve – It would seem that milling in space would be more practical as opposed to printing. Large blocks of aluminum could be stored and then milled as necessary. No heat required. And milling is faster than printing. So I wonder what the logic is behind printing over milling.
Hi Scott,
The only problem with milling is the excess metal particles in a weightless atmosphere of the ISS. Wouldn't that cause a potential danger? Remember, they need to recycle everything up there
Hi Brad–I watched the video a couple of times, and i'm not seeing any insulation between layers of the “stack”. Also, no interconnect details seem to be there. Do you have some clarity on the actual topology of this thing? When I look at it, I see a single cell which uses comb shaped cathode/anode to increase the area.
@eafpres – unfortunately, I don't have any additional info. To your point about is this just one large cell or multiple smaller cells in parallel, while I don't know, I figure if necessary, you could put down an insulating layer as needed. And maybe the interconnections come later.
A very real hazzard with this is the toxicity of the materials that are used and the printing proces i myself am looking at a third surgery due to work in the printed electronics industry
@Pho99 – hadn't thought of that – not sure how well sealed these batteries are – especially for medical applications. I'll look into this.
@Steve, Does 3D printer require any special modifications to work in the space or zero gravity? I thought it can work in the space also without any modification in the operation or its parts.
We have seen 3D-printed carriages, 3D-printed guns, and even a custom-amassed mechanical PC manufactured from 3D-printed parts. But profound in Harvard's enquiry labs, a team is working firm on a 3D printed project that has the prospective to alteration mobile devices as we know this: a fully operative, incredibly tiny, 3D-printed battery.