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Thanks for sharing your thoughts with us. Slightly off-topic, but perhaps interesting enough to keep here: You state that battery fabs are very opaque. Could

Thanks for sharing your thoughts with us. Slightly off-topic, but perhaps interesting enough to keep here: You state that battery fabs are very opaque. Could you tell us some things we might be surprised to learn about battery manufacturing or technology in general? Thank you.

owenversteeg 10y ago
You're welcome! 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-IonDensity.jpg http://media.greenmonk.net/greenmonk/files/2015/11/Li-IonDen...
- deepGem 10y ago
  Thanks for posting this. A totally unrelated question, if you don't mind answering. Given all this, do you believe that Tesla is changing the battery market dynamics with their GigaFactory. Musk has claimed that their plan is to increase the energy density, but hasn't given out any specifics.
  - nolok 10y ago
    Not parent, but whatever their plan is, energy density is limited by the technology, not the will. It's not like Panasonic could manufacture battery with twice the energy density if they wanted to, with some tech they're hiding in their back pocket. 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.
    - ryao 10y ago
      I think you mean the electro-chemical cell. Batteries are just bundles of electrochemical cells (and 1 cell can be a bundle). I am far from an expert on this, but tighter packing of electrochemical cells could improve density.
      - owenversteeg 10y ago
        > Batteries are just bundles of electrochemical cells (and 1 cell can be a bundle) 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.
        ufo 10y ago
        Why is gravimetric density more important than volumetric density? That sounds counter intuitive to me.
        owenversteeg 10y ago
- yosyp 10y ago
  The stagnation of Li-ion batteries can be attributed to industry approaching the theoretical maximum energy density. So instead of optimizing the remaining 25%-30% capacity, focus shifted to Li-air or Li-S research. Li-S in particular can reach up to 2600 Wh/kg theoretical energy density, or 10x of current state of the art. 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%20sulfur https://www.google.com/trends/explore?date=all&q=lithium%20s...
- ggreer 10y ago
  > 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. 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?
- jdietrich 10y ago
  >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. VTC5?
  - owenversteeg 10y ago
    Haha, glad someone tried to guess! But nope, there are several cells that beat the 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.)
- bigger_cheese 10y ago
  In 2010 I experimented with Graphene as the Anode of a Li Ion battery. The results at the time were pretty promising but we (the lab at my uni) were synthesizing all of the material ourselves - there was no graphene supply chain and it was very expensive. 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.
  - logicallee 10y ago
    multiply with what voltage? sorry I'm being dumb - can you say the number?

owenversteeg 10y ago

You're welcome! 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-IonDensity.jpg http://media.greenmonk.net/greenmonk/files/2015/11/Li-IonDen...

deepGem 10y ago
Thanks for posting this. A totally unrelated question, if you don't mind answering. Given all this, do you believe that Tesla is changing the battery market dynamics with their GigaFactory. Musk has claimed that their plan is to increase the energy density, but hasn't given out any specifics.
- nolok 10y ago
  Not parent, but whatever their plan is, energy density is limited by the technology, not the will. It's not like Panasonic could manufacture battery with twice the energy density if they wanted to, with some tech they're hiding in their back pocket. 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.
  - ryao 10y ago
    I think you mean the electro-chemical cell. Batteries are just bundles of electrochemical cells (and 1 cell can be a bundle). I am far from an expert on this, but tighter packing of electrochemical cells could improve density.
    - owenversteeg 10y ago
      > Batteries are just bundles of electrochemical cells (and 1 cell can be a bundle) 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.
      - ufo 10y ago
        Why is gravimetric density more important than volumetric density? That sounds counter intuitive to me.
        owenversteeg 10y ago
yosyp 10y ago
The stagnation of Li-ion batteries can be attributed to industry approaching the theoretical maximum energy density. So instead of optimizing the remaining 25%-30% capacity, focus shifted to Li-air or Li-S research. Li-S in particular can reach up to 2600 Wh/kg theoretical energy density, or 10x of current state of the art. 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%20sulfur https://www.google.com/trends/explore?date=all&q=lithium%20s...
ggreer 10y ago
> 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. 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?
jdietrich 10y ago
>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. VTC5?
- owenversteeg 10y ago
  Haha, glad someone tried to guess! But nope, there are several cells that beat the 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.)
bigger_cheese 10y ago
In 2010 I experimented with Graphene as the Anode of a Li Ion battery. The results at the time were pretty promising but we (the lab at my uni) were synthesizing all of the material ourselves - there was no graphene supply chain and it was very expensive. 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.
- logicallee 10y ago
  multiply with what voltage? sorry I'm being dumb - can you say the number?