Batteries with 50 per cent more energy with pure silicon anode
ecn.nl
ecn.nl
Are there any good websites to gauge battery development progress as opposed to the vital, but often ephemeral research progress.
Cost, Reliability, Capacity
You could list cost of materials, number of cycles with 80 percent capacity left, capacity in Wh/kg.
But it would still be incomplete. Maybe some "driving cycle" style standardized tests for various uses. Also manufacturing scenarios.
Hard to create something non gameable.
"These discoveries usually concern materials that can only be produced in a laboratory environment on a very small scale. What makes our invention so promising is that the technology for mass production of this material is already within reach due to its similarity to an existing production process for solar cells."
Full solution - all with Silicon.
If that's possible - and they can improve the cycle count... or do it cheap enough to make up for a low cycle count... or all of it - improve it, make it cheaper AND under one roof?
Even if that were true, this is a release by a company... they aren't going to give away their technology for other people to use.
That's what licensing agreements are for.
I just think that if I was a solar company that could use my equipment to produce batteries as well? That would be high on the priority list to include in packages...
Companies sure do love bundling things together.
I would expect the battery to be in the basement/garage/etc and not on the roof with the panels.
By what metric..? The amount of energy and power involved in the two uses is completely different. Do you happen to know the bulk cost of silicon, or how much silicon is used in solar cells, or how much of a solar cells cost it makes up, or what process is similar?
You're not doing much more than a kind of free association. For actual context, spheroidal graphite powder is up to $10,000/tonne[1] and metallurgical silicon is around a quarter of that[2].
[1] http://www.mining.com/web/battery-grade-graphite-set-for-rec...
[2] https://www.metalbulletin.com/Article/3208513/Silicon-prices...
The bulk cost of silicon is a moot point. That's like asking how Pizzas can be made more cheaply if you reduce the cost of the flour involved. It's the extreme precision ultra pure processing that makes it expensive, not the bulk materials.
Batteries don't require 6N precision. Silicon anodes can be 99% pure and work fine. Metallurgical silicon is ~99.9%. Only the bottom shelf ferrosilicon stuff is <99%.
My point is that you're making assertions that you don't fully understand. Why would batteries suddenly need extreme precision ultra pure processing? That doesn't make sense.
> It's the extreme precision ultra pure processing that makes it expensive, not the bulk materials.
That's my whole point. The expensive part is left behind because it doesn't have anything to do with batteries. The part that's left over is fancy sand and a mylar-making machine. The same machine used to make the very cheapest solar cells, the kinds in old calculators. The kind of machine that made the monitor you're reading this on. Not the 9N part.
Commercial cells have 500-800 cycles in their lifetime (until their capacity falls to 80%) and are universally made on reel-to-reel machines. There are a ton of difficulties moving from a coin cell to a prismatic/pouch cell to a cylindrical cell, but I can't understate how encouraging it is that they got to 100/400 cycles.
> Are there any good websites to gauge battery development progress as opposed to the vital, but often ephemeral research progress.
Not that I know of, sorry.
Here are some I've thought of, please suggest others:
1. Cost of raw materials - even if the tech improves, will it still be expensive?
2. Charge/Discharge cycle count - thermal and mechanical stresses
3. Power to weight ratio; power to cost ratio
4. Manufacturability - does it require novel manufacturing techniques or can it be integrated into an existing product line
5. Round trip energy losses
6. Safety
Raw materials can be important, but only very rarely and it can also be misleading. By far most of the cost comes from the complexity and time of manufacture. That makes it tricky. For instance sulfur is far cheaper than other anode materials, but there will never be a cheap sulfur battery- it's way too complicated.
It helps to know the basics[1] of battery manufacture: it's a decades old process and highly optimized. The gist is that you apply coatings to a reel of tape. If it sounds like it can't be put on a tape very easily, it will probably fail the sniff test. Solid/ceramic electrolytes and most kinds of nanotechnology fall into this category. Coating a tape is cheap, but using an electron microscope or laser on every battery is not.
>2. Charge/Discharge cycle count - thermal and mechanical stresses >3. Power to weight ratio; power to cost ratio
Critical. Any article, paper or press release will stress the interesting part of the battery; it's up to you to figure out how relevant it is. If the article emphasizes the current capacity, check the voltage of the chemistry. If it emphasizes the energy density, check the power density. If it emphasizes the weight, check the size. If it emphasizes safety, check everything. This is often nontrivial though. It's possible to tweak your numbers to balance things out- if you scale back the storage level you can increase cycle count, etc. If a paper has improved everything, it has a shot at being a next gen chemistry. Of course it may also be bullshit.
In my experience just remembering to check the other attributes of the battery will weed out 90%+ of bad articles. Most people are honest, they're just obligated to play a certain game to keep their funding up. Unfortunately there still are folks who will publish garbage though.
7. Energy density (as opposed to power density; i.e. c-rate matters)
8. Temperature sensitivity (many batteries lose voltage at low temps, e.g.)
9. Ability to hold a charge
This though- this is very cool. If they've actually demonstrated 100 cycles in a pouch cell, made with reel-to-reel, that may mean that commercial cells are <5 years away. More likely 10+ years, as there are any number of things that could shut this down and the tech may not be compatible with cylindrical cells. Regardless, this is one of the most promising sounding press releases I've read in a long time. PVD anodes will be expensive (this is similar to the process to make mylar), but may be comparable to current processes, which require a long, temperamental and expensive solvent + drying process. PVD could even make this process more reliable (fewer failures) and consistent.
Commercial cells have 500-800 cycles in their lifetime (until their capacity falls to 80%) and are universally made on reel-to-reel machines. If it can't be done on reel-to-real it can't be done cheaply. There are a ton of difficulties moving from a coin cell to a prismatic/pouch cell to a cylindrical cell, but I can't understate how encouraging it is that they got to 100/400 cycles. It's near unheard-of with fully silicon anodes.
This is also quite promising for future development. When they say 1000-2000 mAh/g they're referring to the anode itself- only the weight of silicon, not the full battery. Silicon tops out near 4000 mAh/g, so there's a reasonable headroom there. 50% increase in overall capacity for the entire battery is fairly conservative. I presume it's because they can only apply very thin layers of anode silicon. That may mean there's a lot of room for growth though! They just have to thicken up that layer.
I'm still very skeptical of their long term capacity though. The problem with anodes like this is the nanoscale features. You basically have a huge tangle of velcro: that's done to increase the surface area exposed to the electrolyte, which solves the anode expansion problem. The drawback is that when that surface area becomes restricted, and it inevitably does, the SEI affects the distribution of li ions inside the silicon, increasing damage. They do appear to have found a way around that, but it may still put a long term limit on capacity. The thicker you try to make the anode (to increase energy density), the deeper the "velcro" becomes, and the more the SEI blocks lithium. It may also make these batteries more sensitive to heat and overcurrent and over/undervoltage- anything that disturbs the SEI may cause dramatic irreversible effects.
Random related fun fact: Silicon requires the use of copper rather than aluminum foils in batteries. Aluminum is a semiconductor dopant (the exact one used in your computer, in fact), and if you deposit silicon onto an aluminum foil it will form a very weak diode that causes a ton of problems. In computers an extremely thin silicon oxide film is used between aluminum wires and the transistors they connect. That layer is extremely resistive and causes a bunch of headaches, but way smaller ones than tiny diodes would!
That has been the conclusion of hundreds of these battery technology stories. We still haven't seen one these to work out yet in the past 20 years.
There's certainly an unending flood of hyped up articles about new experiments, but all of those have some kind of caveat that's glossed over. Cost, manufacturability, or performance. One is always missing. They're usually pop articles or university releases that misunderstand, misquote and play up the papers involved.
This is a release from a private company that hits all three of the important targets. Those are pretty reliable, normally. Flow batteries are an exception, but that's because the professor behind that is way overenthusiastic about them and needs large-scale funding. He's kind of notorious for overpromising; I remember a story by a student under him who used his calculations to derive the scale at which flow batteries became economical and found it was an order of magnitude bigger than a power plant. The professor himself had set up those equations but never actually done them to figure out how big the battery needed to be.
Leydenjar comes off as very conservative in this release. They're announcing an insane improvement, literally decades ahead of when it was expected. Most people would have announced this in coin cells but they waited until they had developed a mass production machine and tested it, and they seem to have replicated those results. Even if this costs 3x more than normal batteries there will be huge demand for it. The battery in an iphone costs $3. Apple wouldn't even blink if a 50% better battery cost $60.
These guys are saying that they pretty much have a product already. Pouch cells make up the majority of batteries that aren't in laptops, teslas or power tools. They've got a manufacturing machine BUILT already and appear to expect a high cycle life. I'm pretty inclined to believe them if they say they can make these affordably.
Apple seems content to merely maintain the status quo of barely a days battery life. I would not expect them to lead the way on this front.
It's challenging to achieve for a new part. It's like there is money for much better and much more expensive... but it doesn't come for free.
(Personally I really wish they'd have a model with a much larger battery, because "lasts one day" really means "usually lasts one day but it depends on how you use it so you can't really count on it." But they won't.)
I will say though, Sadoway is a bona fide friggin genius. I'm still not anywhere close to sold on flow batteries or molten salt/metal batteries, but Sadoway's work is brilliant. He had me genuinely convinced we were about to make all of our steel electrolytically. I still really hope we end up that way.
Because I am pretty sure Apple has enough spare cash to fund it, assuming like you said this really is far into development then everything else.
What does this mean? I feel like I charge my phone more than 500-800 times.
Cycle life increases dramatically at lower depth of discharge, so if you normally recharge your phone when it gets to 10% it'll last twice as many cycles. High temperature and fast discharges will reduce that.
Essentially your phone is rated to be driven to 0% once a day for ~2 years, give or take a bit. Less if it gets hot, which it will, because the battery is used as a heatsink for the rest of the phone.
Coin cells are just really simple. They're pretty standard for proving your battery works. The thing is that there is a huge difference between that and a real useful battery. You can pay a grad student overtime to build a coin cell of about anything. You need a machine to make a pouch cell.
It's like if someone showed you a go-kart and said they could make a car. They share the same elements and everything, but there's a definite world of difference between them. It's a lot more than just being bigger.
Only the ones with removable battery, which AFAIK is a minority nowadays.
http://batteryuniversity.com/index.php/learn/article/types_o...
So until we get over our stupid post-9/11 policies, it doesn't matter if Star Trek batteries magically spring into existence. The tech isn't going anywhere, other than allowing something like Apple Watch to have a little more capacity.
I don't think i'd want a 1Kwh battery on a plane.
This thing might blew my mind. It's a battery-powered drone that you can fly in!
I don't know exactly how big the battery is, but my best guess is that it's bigger than 1Kwh...
It's not vaporware either. There are lots of videos of this thing flying!
Purpose built batteries versus a general purpose battery that could have been engineered to different tolerances are a bit of a different beast.
However, I would love 50% more battery lifetime in my phone without adding more weight or volume.
Or 50% more range in an electric car (or reducing the size/weight/cost of the battery pack).
There are lots of applications for batteries that don't involve taking large batteries on the plane.
If you look at where batteries are going to be in volume in the next 20 years it will be in grid storage, off-grid house energy storage, vehicles, and potentially small industrial tools.
Of course if this particular breakthrough actually makes it into batteries we will all be pleasantly surprised, as battery "breakthroughs" have a success rate quite a bit lower than 'venture funded startups' :-)
So that should be 50% more range or 33% less weight. Not 50% less weight.
But I've never had a laptop with a full 100 watt hours anyway, and even more important is my phone where that restriction is miles away.
This is about entirely replacing the anode graphite with silicon.
Green Car Congress provides good context. This is also a potential manufacturing revolution.
But it's a hard problem because of the massive swelling of silicon during the lithiation, I think during discharge.
As regards the article, Lithium-Silicon batteries have the potential to add much more than 50% to the charge density of Lithium-ion batteries. More like 400% in theory. But nobody has demonstrated a cheap, production-ready process for such a thing, because a charged silicon anode occupies much more space than a discharged one, and the associated mechanical stress is a severe problem. There has been an endless parade of press releases from universities and national laboratories over the past 10 years on this topic.
Meanwhile other chemistries have shown much greater improvements in safety, energy and power, and price is understood to be more about the scale than the chemistry.
https://www.economist.com/blogs/graphicdetail/2017/06/daily-...
Lithium is very poorly mapped. The last time the USGS surveyed it was in the 50s IIRC. For instance, that article is wildly inaccurate. It lists 6.9 million tonnes in the US. A single site, 45 miles to a side, in wyoming is estimated at up to 18 million tonnes of lithium[1]. Then again America may also count as a region of relative political instability.
I'll point out though that if you're gonna bring up political instability, around 20x (up to 60x in cellphones) as much cobalt is used in batteries as lithium, and virtually all of that comes from a single country: Congo. That's political instability. Lithium is a cakewalk by comparison, and fears about it are just manufactured and overblown.
[1] https://oilprice.com/Energy/Energy-General/New-Wyoming-Lithi...
Fascinating stuff and great explanations, thanks!
In 2012 the world produced 4.7 million tonnes of lead metal from mines[1]. If that were lithium, it would be enough for 588 million cars. In 2012 the world made 84 million cars[2], so there's a safety margin of over 7. And that's without even really trying to mine lead. 7.2 billion tonnes of coal are mined each year, almost 2000x more than lead. We would need to mine .0071% as much lithium as we do coal.
[1] https://www.ila-lead.org/lead-facts/lead-production--statist...
[2] https://www.statista.com/statistics/262747/worldwide-automob...
Note though that you're right: there is some potential for the short term (~3 years) price of cobalt to swing. Batteries make up a solid ~50% of global cobalt consumption. That's almost all due to China- in the US almost 70% of cobalt is used for metal-related stuff, mostly superalloys for turbines and jet engines. It's basically a race between new mines being able to ramp up production and the battery revolution taking off. Tesla isn't that worried because while cobalt is important, they can bear a short term cost increase. Tesla has repeatedly said they're under $200/kWh, and even at that price the battery would be $10,000 on a model 3. Of that the current cost of cobalt is probably ~<5%- if the price of cobalt quadruples it's still a total of <$2000. That's almost 6% of the cost- painful, but survivable. And that's an extreme situation.
Another reason they may seem blase is that cobalt is far from the biggest single cost in the battery. It's just the most potentially volatile. Only about 9% of the cathode is cobalt (in NCA), and nickel and even graphite are much bigger costs. Those two are significantly more stable- graphite can be made fully synthetically in a pinch (currently ~45% of battery graphite is synthetic[1]) and nickel consumption is already so huge (because of stainless steel) that even if every car was electric, it would hardly affect our nickel consumption. Cobalt prices can go up quite a lot before it actually affects Tesla's bottom line, but nickel and graphite will affect it immediately. In the end they all roughly balance out.
[1] more info: Synthetic graphite is made from high quality anthracite coal or refinery tar (asphalt, bitumen) that is heated in an oven (carbeurized, then graphitized) and then ground in a ball mill (then chemically treated, plus a whole bunch of proprietary voodoo). It's roughly the same cost as natural spheroidal graphite (the kind used in batteries- think best of the best of the best) and even cheaper sometimes, but they have different qualities. Natural graphite has a slightly higher capacity, while synthetic graphite has higher power capacity, so they use both in a blend. 90% of making batteries is picking the right blend for your application- there are hundreds of every ingredient to mix, tweak and balance. Competition is achingly incremental and fierce.
My general perspective is that Tesla should derisk the miners by putting some money upfront on a contractual basis. Maybe it's Panasonic that does this. I'm happy to see that the rumor is the price spike to 25$\lb was brought on by hedge fund speculators. I think that's a perfect example of how Wall Street greed is actually good. The high price signal helps motivate the entire supply chain.
Thanks for your lengthy answer.
heh
> My general perspective is that Tesla should derisk the miners by putting some money upfront on a contractual basis. Maybe it's Panasonic that does this.
I think they have a long term supply deal with Sumitomo Metal Mining[1] (Phillipines, not Indonesia, my bad), but I'm not sure if there's money up front.
It's my personal opinion that the industry is well prepared for a drastic increase in cobalt demand. I'll also point out that laptops and cell phones put a very large buffer in place for NCA and NMC chemistries. Laptops and cell phones use LCO which is a 100% cobalt oxide cathode. A high supply pressure will cause them to switch to low-cobalt chemistries like NMC and NCA, or even to completely non-cobalt chemistry. That'll free up cobalt for all batteries. LCO is becoming less popular but AFAIK it's still the majority of batteries by kWh and certainly by use of cobalt.
[1] https://evobsession.com/sumitomo-metal-mining-boosting-nca-u...