Unfortunately, I'm mostly on the supply side of the battery equation, consuming those few PDFs that are smuggled out.
The most surprising thing, to me, is that battery tech moves in a zig-zag shape. The best battery that money can buy, for two of pretty much the most important applications (can't elaborate further, sorry) was only made from ~2012 until ~2014. A lot of really expensive things that need that battery are now running off of old stock, which will of course eventually run out. The best comparable battery made in 2016 has less than half its performance.
Another example of this is energy density. For practical purposes, the best density you could reasonably buy was fixed around 90 Wh/kg for a while (until about 1997), then suddenly jumped to ~180 Wh/kg (~2002), then went in 2006 to ~260 Wh/kg... and sat there, where it has sat for eleven years now with practically zero improvement. [0] If I teleported to today from 2006 I'd expect to have some fantastic 400 Wh/kg batteries that would enable all kinds of new technologies... but nope, the best energy density you can get is literally the same as it was eleven years ago.
Worth noting that since 2006 discharge rates of high capacity batteries have gone up, to be perfectly fair. Still though, energy density remains stagnant.
[0] Looking at graphs on Google Images will give you the wrong idea. They typically show the best batteries that year, not necessarily ones you can actually buy, and the numbers are often pulled out of thin air. This graph [1] is the least worst, but that's not saying much.
[1] http://media.greenmonk.net/greenmonk/files/2015/11/Li-IonDen...
As for the "gigafactory", it's Tesla trying to get into that closed market, like parent said there are only a few big players and it's not very welcoming to new ones, Tesla's plan is to be so big that they can have a big supply to sell in bulk AND to also be (together with solar city I guess) one of their first big scale customer.
Correct. The problem with packing cells tighter is heat production: a ridiculous amount of heat is released and the individual cells can get up to 80 degrees C / 176 F. (80C is not a "doomsday scenario"; most cells are rated to sit there running at 80C just fine.) When they're all next to each other, tightly packed in with no place for heat to go, you're screwed.
The other reason is that volumetric density is usually not what people optimize for; gravimetric density is more useful most of the time, and in that case you don't really have any reason to use tighter packing.
- Electric vehicles
- Aircraft
- R/C
- Anything that goes into space
- Large scale energy storage (good energy density typically = less lithium used)
- Generally: anything that moves
Places where both are equally important:
- Consumer electronics (you don't want an ultra slim 2lb phone, or a ultra thick featherweight phone)
Places where volumetric density is more important:
- Batteries in smartcards
- Some medical devices
- Certain flashlights, IoT devices
You'll notice that there are a lot more things where people care more about gravimetric density.
Also, the best Li-Ion cells for volumetric density that you can buy are rather inconvenient shapes; a favorite is the 18650, an 18mm diameter by 65mm long cylinder. Yes, the best 18650 technically has much better volumetric density than the iPhone batteries. But if you swapped the iPhone battery with an 18650 you'd have a hilarious looking semi-cylinder protruding from the back.
Spot on. Musk is a fascinating guy but he's not magic; energy density hasn't improved in 11 years with ridiculous amounts of cash thrown at it and I don't think Tesla will be the one to make a breakthrough.
> As for the "gigafactory", it's Tesla trying to get into that closed market
Tesla is actually partnered with Panasonic, which is one of the big battery makers and one of the three that actually make cutting-edge cells. Tesla's "plan" as far as I can tell is to make and sell batteries as cheap as they can, especially since the cells they are making right now aren't interesting in any other aspect than price.
TL;DR They're changing the market dynamics but their cells are boring aside from being cheap and will probably stay that way for a while.
So first of all, yes they will change the market dynamics; anyone selling as many batteries as they (plan to) do will change the market.
Secondly, the gigafactory's cells aren't that interesting (right now) aside from being cheap. The cell lifetime is atrocious, between half to a quarter that of the market standard. The energy density is not great, around 220 Wh/kg for the best cells and 190 Wh/kg for the worse ones; this is slightly better than the cutting edge fifteen years ago. The power density they claim is unacceptable given what it does to the cell life. And since the cells are larger, they require new cooling systems.
Musk is a fascinating guy, for sure, but he's just as human as the rest of us. An absolutely gargantuan amount of cash has been piled into battery research in the last 11 years, with zero appreciable gains in energy density. If the Gigafactory ever produces a high energy density cell, it'll almost certainly be because their partner Panasonic (which is one of the few battery companies on the cutting edge) made a breakthrough and licensed it to them.
Finally, the battery market is a very strange thing: many makers of the 'good' cells won't sell to anyone except a few specific clients. These clients buy the cells (on paper) to make things like power tools or electric vehicles or battery packs. However, these clients vastly over-buy, and then sell off their excess stock to resellers. Anytime you buy a powerbank, or a loose 18650 cell for an e-cigarette, or a battery pack for an ebike, you're almost certainly going to end up with cells that have been resold at least twice.
As such, the easiest way that Tesla could absolutely revolutionize the industry is by simply saying "hey, if your needed capacity is more than $25K per year, give us a call" and selling directly to businesses. They could even put up a quote on their website à la SpaceX. Unfortunately, I've got a feeling that if Tesla did that their partners at Panasonic would make heads roll, but you never know.
But yes; if you want newer battery technology direct from the manufacturer, you'll probably be flat-out ignored even if you're inquiring at a medium-large scale. The way to do it is to hunt around for semi-reputable resellers, who will usually give you what you want at an acceptable price.
Edit: https://www.e-cigarette-forum.com/forum/blog-entry/list-of-b...
I've primarily seen them used for industrial/military applications.
Maybe you can shine some light on this, why do the search trends [1] for lithium sulfur appear so cyclic? I'm not aware of any uses in industry, or any major conferences/press cycles around Li-S.
[1] https://www.google.com/trends/explore?date=all&q=lithium%20s...
Don't lithium ion batteries degrade over time? If that's the case, then how is this 3-5 year old stock still the best available?
We always talked about specific capacity (q, charge per unit weight) so all the numbers I'm quoting will be in that - you can multiply by voltage to convert.
We were obtaining specific capacities around 500 mAh/g. Vs q= ~370 mAh/g max for graphite anode. I recall based on theoretical modelling ~660 MAh/g could have been achievable with graphene.
This pales in comparison to tin or cobalt anodes, which back in 2010 had q = 990 or so. We were not really optimizing for energy density. Rather with carbon based anodes we would see much better cyclical performance due to the lower volume expansion during Li intercalation. So you would be able to get much more charge/discharge cycles without the loss of performance you'd typically see in a higher energy density metal based anode.
I work in a different industry now and have not followed battery development closely. I'd speculate a similar thing has happened in the "real world" the energy density may not have improved significantly since 2006 but the cycle life is probably better.
VTC5?
Two that come to mind immediately (that beat the VTC5) are the 25R and the VTC6, both of which run cooler and have a higher capacity than the VTC5.
You probably haven't heard of the specific battery I'm thinking of unless you've worked a decent amount with batteries, though; it's not terribly popular with hobbyists (part of that, of course, is that it can be hard to get.)