3D printed batteries: here comes the future
Advances in 3D printed batteries over the past few months point to the real possibility of a future of cheaper, more energy dense batteries that can be customized for application and shape.
The idea of 3D printing batteries is not entirely new, in fact the first one was made by a team led by Jennifer A. Lewis at Harvard University in 2013. They created a customized printer and special anode and cathode inks to produce a lithium-ion battery, but it wasn’t able to power much. It was only about the size of a grain of sand.
Skip forward 7 years and two companies – Blackstone Resources of Switzerland and KeraCel in the US, have both made significant leaps toward the technology and procedures needed to create full 3D printed batteries.
KeraCel received a key patent for ‘for its innovative monolithic solid state battery incorporating a sealed anode structure’ and Blackstone announced the successful testing of “functional battery cells manufactured with thick, printed electrodes”.
There is also news from Singapore and China where researchers have demonstrated a way to make flexible 3D printed batteries for wearable electronics.
Three main benefits of 3D printed batteries
While batteries have obviously made huge strides since the advent of the lithium-ion chemistry in the 1990s, there are three things everyone wishes could be solved.
The first, not surprisingly, is price. The other big one is energy density – how to get a battery to hold more electricity, thus making them lighter and/or smaller. The third thing, not quite as crucial as the first two but still important, is being able to build batteries that give the designers of electric devices more choice on the size and shape of the battery.
When it comes to electric vehicles and electric boats, the battery modules that are used are all basically a bunch of smaller household sized batteries fastened together to increase the capacity. The Tesla 85kWh pack, for instance is made up of 7,104 cells roughly the size of AAs. This image is from a video (see full video below) of a Tesla pack being pulled apart by the man who built the world’s fastest electric ski boat.
That construction method severely limits the options for where you can place a battery pack, which is maybe even more important for an electric boat than it is for an EV. A company named XING mobility makes modular packs that can be made into a variety of shapes, kind of like Lego®, but the configurations are still somewhat limited.
With a 3D printed battery, the process of putting together a module is essentially reversed. The individual cells don’t have to be manufactured and then put together, the module is designed as a whole and then printed to match.
Porous electrodes improve energy density
That’s an idea of how 3D printed batteries are different in ‘the big picture’, but they are also different at the smallest micro and nano levels.
To understand how, it is probably better to think of the process not as ‘3D printing’, but use the industry term: additive manufacturing. Rather than using nozzles to squirt out a continuous stream of material like 3D printers you may have seen, this process is more an idea of building up something from nothing using customized bits of material at every level and stage of the ‘construction’.
Down at the nano level, additive manufacturing makes a big difference in the structure of the electrodes of a battery and this is where the increased energy density stems from. It has long been established that ‘porous’ electrodes increase energy density, and additive manufacturing is ideally suited to the process. It means that the materials in the electrode can be built – into a three dimensional lattice.
The lattice means that the electrode has much more exposed surface area where the chemical reactions that make a battery work take place. The result is a more efficient battery.
The other thing that can make 3D printed batteries more energy dense is that the battery modules don’t need extra substances to glue them and wire them together. As you can imagine, the glue and wiring to hold together 7,104 batteries can add up to a fair amount of weight, but those elements are part of the additive manufacturing process, not extra materials.
It’s the same principal as the Prologium battery we wrote about in January. They reduce the amount of connective material in a different way, but in their case “When the energy density of the battery cells is the same, the energy density of the ProLogium Technology’s battery pack can be enhanced by 29% to 56.5%”
‘Double the energy, half the price’
Finally, there’s the price component. One of the main attractions of additive manufacturing in any industry is the cost efficiency. In the case of batteries, there are tremendous savings in not having to manufacture the cells separately and then assemble them into modules.
Once the 3D printing/additive process is set up, the raw materials are put in and the completed, custom configured batteries come out the other end. Blackstone says that the technology “offers more than double the energy density at half the current manufacturing costs.”
Battery technology is crucial to making electric boats more efficient and less expensive and there are literally thousands of companies and researchers working on better batteries. The financial rewards for successful technology are immense.
While Blackstone and KeraCel are leading the pack in automated 3D printing/additive manufacturing of batteries, it is almost guaranteed that more will join them.