An important step to better lithium-ion batteries can be found in Whoop's latest wearable

nanoguy

Posts: 1,021   +14
Staff member
Why it matters: It often seems like battery technology hasn't been keeping up with advances in compute power for the tiny chips that power mobile devices. That's because making batteries cheaper and easier to manufacture has been a far easier problem to solve than improving their energy density, charging time, endurance to constant charging and discharging, all while ensuring they remain relatively safe during operation. News of breakthroughs comes and goes, but we now have one that's making it into an actual product, courtesy of Sila Nanotechnologies.

This week, fitness tracking company Whoop unveiled a new wearable that crams a lot of circuitry and sensors into a tiny package that you can comfortably wear on your wrist. It's an impressive piece of kit focused on collecting metrics about your heart rate, sports activity, sleep performance, skin temperature, blood oxygen levels, and more. But what makes this device even more impressive is that it's 33 percent smaller in volume compared to its predecessor while still being able to last five days before needing to be charged again.

What made this possible may seem like a simple change, but it's actually the result of ten years of arduous work from a startup called Sila Nanotechnologies, founded by one of Tesla's early employees, Gene Berdichevsky. The Alameda-based company is backed by BMW and Daimler and has been working since 2011 on finding a better anode material for batteries that would improve their characteristics.

That material is silicon, whose atoms theoretically have the potential to hold ten times the number of electrons when compared to graphite, which is a commonly used anode material. But as other companies researching silicon for use in anodes have found over the years, this isn't easy to translate into practice, as engineers have had to add complexity to the traditional lithium-based battery design to mitigate safety and longevity issues.

The major challenge with silicon is that during charging, it expands to more than three times the original size as a result of reacting with the lithium, and then also contracts more than three times during discharging, posing great risks to the structural integrity of the battery. For reference, graphite only expands around seven percent with charging and contracts seven percent with discharging.

Battery manufacturers such as Panasonic have been trying to solve this in various ways, mostly by adding small amounts of silicon into the anode mix -- typically 3-5 percent, but never more than 10 percent. Companies that tried making pure nano silicon anodes have found the resulting batteries don't last more than 100 charge-discharge cycles without expensive mitigations that would make mass manufacturing unfeasible from a financial perspective. Startups like XNRGI that are etching batteries on silicon wafers are a good example of that.

Sila says it has found a way to eventually replace graphite entirely and allow for up to 20 percent higher energy density while still using existing battery manufacturing techniques. This is one of the main advantages of Sila's silicon anode, along with the fact that the raw materials needed are widely available and thus less prone to global supply shortages.

All of it is made possible thanks to an engineered particle structure that allows the silicon to expand inside of it while keeping the electrolyte outside. In turn, the battery can now be cycled thousands of times without posing any safety issues. Berdichevsky says the anode in Whoop 4.0's battery can last for more than 500 full charge-discharge cycles, which translates into several years of normal use.

That's just the beginning, however, as this battery only has an anode with 25 percent silicon in it, so there's still a lot of room for improvement. Launching the technology inside a small wearable may not look like much, but Berdichevsky is convinced it will gradually "scale and lead to the electrification of everything." He says, "you can translate this success with Whoop to cars in many ways," such as making affordable compact sedans with 400 miles of range a reality in the future.

Getting into EV territory requires a highly-scalable manufacturing process, and the good news is that Sila has had that baked into the company's mission from the very start. It has been developing volumetric reactors that have a much higher production capacity than planar reactors. So far, it has scaled 10,000 times from lab to the latest reactor, which has a capacity of 5,000 liters.

The plan is to scale that up 100 times to a reactor large enough to drive a car through, which would be enough to produce the large amount of batteries required to fill electric cars. Sila is also looking to build a larger manufacturing plant in the next few years, thanks to $590 million raised earlier this year from investors.

We're not there yet, but after more than a decade of promises and billions spent on research that didn't seem to materialize in any meaningful way, things are looking bright for the batteries that will power our electrified future.

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madboyv1

Posts: 1,731   +644
We're not there yet, but after more than a decade of promises and billions spent on research that didn't seem to materialize in any meaningful way, things are looking bright for the batteries that will power our electrified future.
Considering the dozens of advancements and and announcements that "this will change the future of battery tech" hype that have materialized over that decade from labs to marketing, I'd say this is more akin to lighting a new kind of fancy nightlight lightbulb in the middle of a warehouse, but it's better than being in the dark. Someone will eventually work out a bigger, brighter bulb, but at least -something- is hitting the market.
 

Plutoisaplanet

Posts: 571   +924
Great article, I haven't heard about Whoop. It's interesting that they're based in Alameda proper (not the county), which is the only city in California entirely located on an island (technically on three). It's probably a great place to test wearables outdoors though!
 

wiyosaya

Posts: 6,756   +5,197
Considering the dozens of advancements and and announcements that "this will change the future of battery tech" hype that have materialized over that decade from labs to marketing, I'd say this is more akin to lighting a new kind of fancy nightlight lightbulb in the middle of a warehouse, but it's better than being in the dark. Someone will eventually work out a bigger, brighter bulb, but at least -something- is hitting the market.
Yes, I agree. At least this advancement is hitting the market. Another that I am reasonably sure that is hitting the market in the next year or so is from this company https://graphenemg.com/energy-storage-solutions/aluminum-ion-battery/
To give everyone an idea of the promise of silicon in Lithium batteries, this article describes the potential of using silicon to increase the energy storage of lithium batteries by a factor of 10 https://phys.org/news/2019-01-tiny-silicon-particles-power-lithium.html
If this research comes to market, that will be a game changer.
 

nismo91

Posts: 1,165   +206
Wake me up when september ends... or rather when all these "theories" ends up in the market, not when it's sitting as a prototype in the research department.

I have a wearable and I would be thrilled if they could make the batteries more efficient... 1000mah batt in a current size 42mm smartwatch? who doesn't want that? but I'll keep my fingers crossed for now.

 
It's interesting that they're based in Alameda proper (not the county), which is the only city in California entirely located on an island (technically on three).

Alameda is not entirely located on an island. Bay Farm Island is a misnomer - it is a peninsula, not an island.
 

Plutoisaplanet

Posts: 571   +924
Alameda is not entirely located on an island. Bay Farm Island is a misnomer - it is a peninsula, not an island.
Bay Farm Island used to be an island. It became a peninsula through land reclamation, so idk if you could call it a misnomer. That said, I had no clue it is a peninsula before you pointed it out :p
 

umbala

Posts: 458   +754
Another ridiculous pie in the sky battery tech that will never actually happen the way they describe it. First the article says the new anode material has the potential to hold 10x the charge and they've been working on it for 10 years, but then...

"Sila says it has found a way to eventually replace graphite entirely and allow for up to 20 percent higher energy density while still using existing battery manufacturing techniques."

Eventually replace graphite? They've been working on it for a decade and they still have no idea when it will be viable, and even if it is, it will only improve batteries 20% and not 1000% like their "theory" claims. In this context the word "eventually" actually means "never." Just like all those other battery technologies we see every other months this will also NEVER happen.