
Tesla battery researcher unveils new cell that could last 1M miles - Osiris30
https://electrek.co/2019/09/07/tesla-battery-cell-last-1-million-miles-robot-taxis/
======
guerby
Two things missed by the electrek piece:

\- The article is CC-BY and downloable without scribd horrible UI:
[http://jes.ecsdl.org/content/166/13/A3031](http://jes.ecsdl.org/content/166/13/A3031)
PDF direct
[http://jes.ecsdl.org/content/166/13/A3031.full.pdf](http://jes.ecsdl.org/content/166/13/A3031.full.pdf)
HTML direct
[http://jes.ecsdl.org/content/166/13/A3031.full.html](http://jes.ecsdl.org/content/166/13/A3031.full.html)

\- In the conclusion the authors mention: Full details of these cells
including electrode compositions, electrode loadings, electrolyte
compositions, additives used, etc. have been provided in contrast to
literature reports using commercial cells. This has been done so that others
can re-create these cells and use them as benchmarks for their own R+D efforts
be they in the spaces of Li-ion cells or “beyond Li-ion cells”.

So it's science as it should be!

~~~
nwallin
> Full details of these cells including electrode compositions, electrode
> loadings, electrolyte compositions, additives used, etc. have been provided
> in contrast to literature reports using commercial cells. This has been done
> so that others can re-create these cells and use them as benchmarks for
> their own R+D efforts be they in the spaces of Li-ion cells or “beyond Li-
> ion cells”.

That's incredible.

Normally I walk into these wunderbattery threads expecting to heap
reproducibility scorn (we're still waiting for solid state glass batteries,
and will in all likelihood be waiting forever) but pathways to reproducibility
aren't something I'm used to in battery vaporware.

I'm actually excited for battery tech, which seems weird given all the
disappointment over the previous decade or two. Feels like being excited for
another cancer cure in mice.

------
zaroth
Post of the actual paper;

[https://news.ycombinator.com/item?id=20908726](https://news.ycombinator.com/item?id=20908726)

For those commenting that the discharge rate is too slow in the test, or the
depth of discharge was fudged... the tests were run with a high discharge rate
combined with 100% charge at storage.

> Figure 23 shows the projected fractional capacity of these NMC532/graphite
> cells as a function of time in years in a scenario where the cells are
> cycled once per day (100% DOD to 4.3 V) in a cycling event that takes 6
> hours. It is also assumed that during the remaining time, cells are stored
> at full state of charge. It is clear from Figure 23 that these cells would
> provide an exceptionally long total driving range in an EV if the cells were
> maintained at an average tem- perature of 20°C. Even if the cells were
> continually at 40°C, 10 years of lifetime to 70% capacity and a total driven
> distance of 1,200,000 km is projected. It is worth noting that only 3650
> cycles would be required for this total driven distance and 3700 cycles have
> been demonstrated in Figure 16.

> Most important to realize is that Figure 23 assumes 100% DOD cycling on
> every cycle and storage at full state of charge. If the reader reviews the
> literature data in Figures 1 and 2, the reader will realize that the
> lifetime will be much better in situations where the DOD is limited and in
> situations where cells are stored at lower states of charge. Admittedly, the
> projections in Figure 23 use the incredibly simple model described by
> equation 1. It is our opinion that more sophisticated models will lead to
> even longer lifetime projections.

~~~
Osiris30
Would this be a correct summary of the paper?

1) eliminates Cobalt

2) improves energy density (more range)

3) faster charge rate

4) less SOC (state of charge) swing, meaning less cost & weight

4) 5x longer lifespan

~~~
hwillis
1) 532 is not a new chemistry. It's not even the lowest cobalt chemistry;
there's 511 and 811 beyond that (811, or 80% nickel, 10% manganese, and 10%
cobalt, is not yet technically feasible).

2) Range is decreased. 532 has lower energy density.

3) Maybe..? But nothing truly significant. The additives in this chemistry
mean a lot of heat gets generated during charge/discharge. Heat is the
limiting factor during charge, so swapping directly to this would mean lower
top charging speed. However with better cooling... maybe? It can sustain high
charge current for longer, but not as high overall.

4) The buffer for EVs is ~10%. It's not a big factor in cost or weight.

5) Yes, 5x longer lifespan. The caveat is that they havent actually tested >3
years, but IMO this is probably a 50 year battery. The paper is more
conservative and gives it 20 years.

This will be pretty enormous for grid storage, since a battery that lasts 5x
as long costs 5x less. It may be important for trucks and buses, since they
are much higher mileage and will want to run at 100% depth of discharge. Cars
on the other hand run closer to 20%, where normal batteries will also last for
many thousands of cycles.

~~~
DuskStar
> since a battery that lasts 5x as long costs 5x less.

This is only true if there is an inflation-adjusted discount rate of 0%, which
is unrealistic even in this era of low interest rates. Adjusted for inflation,
paying $10 now and again at years 10, 20, 30 and 40 is better than paying $50
up front would be. (By adjusted for inflation, I mean that the $10 you pay in
10 years might actually be $11, but still $10 in 2019 dollars)

~~~
BubRoss
That's assuming that batteries would stay the same price while currency
inflates.

~~~
DuskStar
It's assuming that the item you're purchasing would maintain the same _real_
price. If it cost $10 to start, and after 10% inflation the battery now costs
$11, this holds. (Well, it holds if you have some way to beat inflation with
safe returns. US government bonds _often_ but not always meet this
requirement)

In the case of batteries specifically, I think it's likely that prices drop
even without adjusting for inflation. This makes the price advantage even
clearer.

~~~
BubRoss
What you are saying doesn't even make sense. The original comment was that a
battery that lasts 5x as long costs 1/5th the price over time, and your
hypothetical is buying a much cheaper battery for some reason. There is no
reason to play semantic games with the time value of money, it is clear what
the original person was saying.

~~~
DuskStar
My point was that as lifetimes get longer, value does not scale linearly.
Would you pay 1000x as much for a battery bank that would last until 12019, or
would you assume that it would be made obsolete at some point over that
period? Maybe we've all moved to fusion, and grid-scale storage is useless. Or
perhaps prices decreased by 10x over the next 20 years, and so getting a 20
year battery + a 9980 year battery would only cost 2+998/10=101.8 times as
much as the original 10 year instead of 1000 times.

Time value of money is important, and IMO would be enough on its own. But
opportunity cost from excluding future improvements matters too - and given
the improvements in battery tech over the past decade, one that would
certainly be relevant over the next _five_ decades.

------
Osiris30
Short thread commentary on the paper by Ric Fulop (co-founder of A123 battery
co. and current CEO/founder of Desktop Metal):
[https://twitter.com/ricfulop/status/1170527207657263104](https://twitter.com/ricfulop/status/1170527207657263104)

------
manmal
This is very exciting. BEVs that were made before 2016 (I think that was when
the last breakthrough trickled down to BEVs in the market) typically had a
battery lifetime of about 70k miles or maybe a bit more before reaching 70%
capacity. Fast-charging regularly might reduce capacity by several percent
points within a few hot summer months. Basically, you bought a car for €30k
and it might become useless 5-7 years later. Within a couple of years, we have
gone from "I don't know, it's a bit risky to buy" to "My grandkids might be
able to use this battery in their static storage system in a few decades".

~~~
MrRadar
I think that was mainly due to early EVs having low battery capacities in
general (because batteries cost a lot more then) so daily commuting would
cycle them much more deeply than current high-capacity models. This 2017
article[1] shows battery life data for hundreds of Tesla Model S's (which have
always come with large-capacity batteries). One of the highest-mileage cars in
their data pool had just over 220k km (137k mi) on its battery with 90% of the
original capacity remaining. There are also a few outliers with under 100k km
that are below 90% capacity, I suspect those are cars that have been subject
to a lot of long drives and supercharging.

[1] [https://www.greencarreports.com/news/1110149_tesla-model-
s-b...](https://www.greencarreports.com/news/1110149_tesla-model-s-battery-
life-what-the-data-show-so-far)

~~~
manmal
The difference in lifespan that I mentioned occurred in packs of similar
sizes, for all manufacturers but Tesla. Tesla is in its league when it comes
to battery lifespan.

------
ianai
Can anyone tell whether this is a solid state electrolyte? I’m still hooked on
what I saw in that Netflix documentary where the guy was able to cut and
puncture the battery without combustion. Also seemed capable of being much
more dense.

~~~
hwillis
It is not. This is a fairly conventional cell, with a different crystal
structure for one of the ingredients, and a tweaked mix of liquid
electrolytes.

The most important part of this paper is that they actually prove that
optimizing for cycle and calendar life can have such incredible effects.

~~~
Zenst
Will we end up with seasonal battery's? Many already accustomed to switching
tiers in winter. Whilst temperature management of batteries would cover many
aspects, some locations a better tuned battery would make it more efficient
overall perhaps.

EDIT [s/riers/tires/;sleep]

~~~
hwillis
Very unlikely. Winter batteries aren't a huge problem as long as you are
gentle until the pack is warm. Hot batteries are more of an issue, as they
don't really like temperatures above 90-100 F. Keeping the battery at half
charge helps reduce that damage a lot.

Ultimately if you live in a hot climate the best thing to do is have a cool
garage. The higher heat while out and about is not an issue, just the constant
level of high heat. The only people who would get a real benefit from high
temperature batteries are those without. Batteries are much more expensive
than tires and the market is smaller.

~~~
inflatableDodo
Was wondering about if you could put a liquid coolant loop from the battery to
the charging socket on the car, then have a heat exchanger in the plug and run
water to and from it using a jacket round the cable, so you can have a rapid
charge that also helps heat your bath water.

~~~
hwillis
A supercharger tops out at 250 kW throttles down when the battery pack gets to
~115 F. Hot water heaters run from 120-140 F. Domestic circuits at at most
~7kW, so you'll realistically never be able to do anything useful with the
waste heat. At low power like that battery charging is 98-99% efficient.

Another problem is that the coolant loop needs to be kept quite clean. The
fins are only about a few millimeters wide and in some cars (eg Model 3)
they're electrically hot. Any grit or buildup making its way into the system
is a huge problem and just having a valve that can open can cause problems.

~~~
inflatableDodo
I'm talking about having a domestic supercharger. You can get up to 70kW at
the company head fuse as a standard residential customer in the UK. You can
also go higher, but you have to apply for a quote, so at the moment getting a
true domestic supercharger is a bit pricy.

However, they are going to have to upgrade it all anyway if we get loads of
electric cars.

As for the coolant loop, I wasn't suggesting to have a valve that can open,
just a closed loop to the socket and a heat exchanger that then heats the
water flowing through the handle of the plug.

You then store the water in an insulated tank and use it as a preheated supply
feeding your main water heating system.

------
elihu
Having a cell that tolerates 100% discharge seems like a big deal, if it has
similar energy density to other modern cells. A lot of lithium-ion cells
shouldn't be discharge to less than 20% capacity or so, as it damages the
cell.

------
jokoon
I'm sure batteries would be immensely better if the military would spend money
into research towards better batteries.

~~~
hwillis
As someone who works in gov contracting, please no. Spend money literally any
other way. Give it to the DOE. Fuck, just signing Musk a check would probably
be better. The DoD is _singularly_ ineffective.

------
coin
> last 1M miles

It sort of depends what type of vehicle is attached to it

------
Animats
OK, so if this is so great, when does it appear in the iPhone, which always
seems to have battery life problems?

~~~
std_throwaway
It would make the phone thicker which is not going to happen.

~~~
thekyle
How much thicker?

~~~
scrungus
[https://www.solidsmack.com/wp-
content/uploads/2019/02/Energi...](https://www.solidsmack.com/wp-
content/uploads/2019/02/Energizer-Smartphone-Battery.jpg)

bonus:
[https://i.redd.it/og0o0b3cr8a31.png](https://i.redd.it/og0o0b3cr8a31.png)

------
sandworm101
>> The new battery tested is a Li-Ion battery cell with a next-generation
“single crystal” NMC cathode and a new advanced electrolyte.

If this is anything like growing single-crystal parts for aircraft, it won't
be cheap. The real question should be whether these new battery modules will
last twice as long while remaining less than twice as expensive.

>> Controlling the charge to less than 100% state-of-charge also helps push
the longevity.

Um, that is cheating. Running any battery at less than capacity will extend
its life. You could put two batteries in the car, run them at 50% or alternate
between them, and get double the life. No prizes for that.

~~~
jbm
> Um, that is cheating. Running any battery at less than capacity will extend
> its life. You could put two batteries in the car, run them at 50% or
> alternate between them, and get double the life. No prizes for that.

Don't phones already do this? (IE: 100% is not really 100%, 0% is not really
0%.)

I don't see it as cheating, it's akin to the practical limit vs. the actual
limit

~~~
zeta0134
Many laptops do it too. Lenovo even markets it as a visible (and annoying)
power management feature. Most however simply handle the charge cycles behind
the scenes, and adjust their definition of "100%" over time, so the user can
remain blissfully unaware (and less likely to change the setting).

I don't mind this really. Batteries degrade over time; that's kinda just how
they work, and I'd much rather have 100% mean "my device is done charging" and
0% mean "my device can no longer run." The specifics of what voltage or charge
level or whatever actually translates to those numbers is not important, and
honestly the battery / laptop manufacturer probably knows the right settings
for those better than I ever will, so it's fine.

~~~
Marsymars
> Lenovo even markets it as a visible (and annoying) power management feature.

I wish macOS/Windows allowed this natively. I'm travelling this week with my
Macbook, but it's been docked for the past couple months at 100% charge. Would
be better for the battery if I could keep it at 60% charge until I plan on
travelling.

------
fake-name
"Miles per battery" is possibly the stupidest metric to use to describe a
battery capacity.

Any battery can last one million miles if it's just sitting on a seat in a
vehicle.

~~~
bryanlarsen
I think it's the best metrics I've seen in a while.

"For usage where our previous battery gets 300,000 - 500,000 miles, this gets
a million miles". It's a real world number.

