Tesla battery research group: new high-energy-density battery that could last 100 years

[voyager]

Tesla battery research group unveils paper on new high-energy-density battery that could last 100 years

Tesla’s advanced battery research group in Canada in partnership with Dalhousie University has released a new paper on a new...

electrek.co

"The paper describes a nickel-based battery chemistry meant to compete with LFP battery cells on longevity
while retaining the properties that people like in nickel-based batteries, like higher energy density,
which enables longer range with fewer batteries for electric vehicles."

 

[Electroman]

First off this is not one of those "breakthrough" news coming from dime a dozen fly by night battery research / marketing outlets. This is from Tesla's own Prof. Dahn.

Key points:

Sustain high temperature

"The NMC532 cells, when constructed with only sufficient graphite to be charged to 3.80 V, have an energy density that exceeds that of the LFP cells and a cycle-life that greatly exceeds that of the LFP cells at 40 °C, 55 °C and 70 °C. Excellent lifetime at high temperature is demonstrated with electrolytes that contain lithium bis(fluorosulfonyl)imide (LiFSI) salt, well beyond those provided by conventional LiPF6 electrolytes."

Sustain high lifecycle:

The cells showed an impressive capacity retention over a high number of cycles. The research group even noted that the new cell described in the paper could last a 100 years if the temperature is controlled at 25C:

What is missing from that article is an actual number for energy density "?? wh/kg", although there is claim of higher density than LFP chemistry.

 

[Electroman]

CleanTechnica - today: How Profitable Is Each Car Tesla Sells? 4.5× More Than Each Ford Or GM Car

Wrong topic.

 

[JRP3]

It's targeted at grid storage so the Wh/kg isn't important. They give up some capacity but extend cycle life a lot by using a lower voltage, plus likely some proprietary additives.

 

[Electroman]

It's targeted at grid storage so the Wh/kg isn't important. They give up some capacity but extend cycle life a lot by using a lower voltage, plus likely some proprietary additives.

Thanks. Didn't see any reference to this being a grid storage solution, or maybe I missed it.

 

[JRP3]

Applications that require immense cycle life, such as stationary energy storage, EV batteries serving as vehicle-to-grid storage or battery leasing services can benefit from such cell designs as cost per unit of lifetime energy throughput is definitely superior for low voltage NMC compared to LFP cells. The initial cost imbalance can possibly be alleviated as recycling efforts are improved and lower the economic pressure on certain resources, such as cobalt and nickel. 57

At all cycling temperatures considered, low voltage NMC532 cells provided superior capacity retention compared to both LFP cells and NMC532 cells balanced for and operated up to 4.20 V. Therefore, similar cell designs with similar materials should receive consideration for applications that demand the highest lifetimes.

To my thinking EV specific cells should emphasize higher energy density over super long lifetimes. For EV use these seem to be about the same density as LFP but with higher upfront cost. That cost difference is made up over the long term in stationary storage but probably not in average vehicle use, though V2G may change that equation.

 

[ZenRockGarden]

First off this is not one of those "breakthrough" news coming from dime a dozen fly by night battery research / marketing outlets. This is from Tesla's own Prof. Dahn.

Key points:

Sustain high temperature



Sustain high lifecycle:


What is missing from that article is an actual number for energy density "?? wh/kg", although there is claim of higher density than LFP chemistry.

Yeah a specific number or range would be nice. We can imply that it's above the LFP region of ~150 Wh/kg but below the best existing NMC of more like 250 Wh/kg. I'm talking pack-level efficiency there - per-cell efficiency is higher.

The significantly lower energy density on LFP is why we see it mostly in fixed storage, and in pouch-cell format for cars since pouches pack a bit more battery per unit volume and get them to a reasonable standard-range pack that fits in the same dimensions of an NMC cylindrical pack.

 

[JRP3]

We can imply that it's above the LFP region of ~150 Wh/kg but below the best existing NMC of more like 250 Wh/kg. I'm talking pack-level efficiency there - per-cell efficiency is higher.

I've not seen any NMC with pack level density near 250 Wh/kg. The paper compares the cell level gravimetric energy as follows:

When these cells are compared on the basis of gravimetric energy density, at the stack level, they are remarkably similar with the NMC532 cells delivering approximately 210 Wh kg−1 and the LFP cells delivering approximately 210 Wh kg

 

[ZenRockGarden]

I've not seen any NMC with pack level density near 250 Wh/kg. The paper compares the cell level gravimetric energy as follows:

I believe the full pack 2170 density as seen on the model 3/Y is around 240 give or take how much of the surrounding support gear you count in the weight of the pack, and if you measure the full theoretical KWh of the pack or the operating amount with a few reserved KWh at top and bottom taken off the total...

 

[JRP3]

I believe the full pack 2170 density as seen on the model 3/Y is around 240 give or take how much of the surrounding support gear you count in the weight of the pack

That might be for just the modules, the pack weight in total is about 480 kg, 1060 lbs, for 82kWh. Your numbers would put it at 341 kg, 750 lbs.

 

[ZenRockGarden]

That might be for just the modules, the pack weight in total is about 480 kg, 1060 lbs, for 82kWh. Your numbers would put it at 341 kg, 750 lbs.

Agree - I had a lower weight for the "pack" - I'll defer to your figure which would give pack-density more like 170-180 Wh/kg

 

[ggies07]

It's targeted at grid storage so the Wh/kg isn't important. They give up some capacity but extend cycle life a lot by using a lower voltage, plus likely some proprietary additives.

It seems like that is the best use case for it, but then there is this:

• 2.
  Superior impedance characteristics for fast charging: NMC-type positive electrodes have their minimum charge transfer resistance near 50% lithiation, and during operation increases in impedance or internal resistance are often assigned to increases in positive electrode impedance. 47 Additionally, the positive electrode and therefore cell impedance gets large near 0% positive electrode lithiation, 47 corresponding to 100% state of charge in a normally-balanced NMC cell. This means that devices which implement fast charging methods tend to decrease the charging rate as cells get closer to "full charge." Figure 6 shows that in the 3.80 V balanced NMC532 used here, features in the impedance spectra, including charge transfer resistance get smaller at 100% state of charge, at the cell level. This may mean that fast charge protocols need not reduce charging rate as severely as batteries reach "full charge."

 

[MC3OZ]

Looks like they have added Cobalt to a LMNO battery lowered the voltage and really improved longevity.

Energy density the same as LFP, previously LMNO was higher energy density but needed stuff like dopants and coatings to achieve long cycle life?

I would be interesting to know if Tesla is still proceding with LMNO development.

 

[carterm2]

First off this is not one of those "breakthrough" news coming from dime a dozen fly by night battery research / marketing outlets. This is from Tesla's own Prof. Dahn.

Key points:

Sustain high temperature



Sustain high lifecycle:


What is missing from that article is an actual number for energy density "?? wh/kg", although there is claim of higher density than LFP chemistry.

Prof Dahn is also

Tesla battery research group unveils paper on new high-energy-density battery that could last 100 years

Tesla’s advanced battery research group in Canada in partnership with Dalhousie University has released a new paper on a new...

electrek.co

"The paper describes a nickel-based battery chemistry meant to compete with LFP battery cells on longevity
while retaining the properties that people like in nickel-based batteries, like higher energy density,
which enables longer range with fewer batteries for electric vehicles."

Dr Jeff Dahn also works for Novonix... Dr. Jeff Dahn - Novonix

I understand that Tesla has a contract with Dalhousie University until 2026 which is where Prof Jeff Dahn's Battery Lab is centered.


There are multiple authors of the research... I am not sure who benefits from the discovery directly, likely the company that has the most interest and moves quickest.

MICHAEL METZGER​

Michael Metzger

www.dal.ca

 

[JRP3]

It seems like that is the best use case for it, but then there is this:

True, if it can charge fast enough it might make sense to give up some range for quicker charge times.

 

[ggies07]

True, if it can charge fast enough it might make sense to give up some range for quicker charge times.

I wonder as the Supercharger network is built out, if the public would want only 200 mile range for say a 10-15 charge time....

 

[JRP3]

That doesn't seem like enough since it can be drastically less than that in cold snowy weather.

 

[ggies07]

That doesn't seem like enough since it can be drastically less than that in cold snowy weather.

You're right and I've been thinking about that since I posted....so may like 220? 20 miles for degradation....

 

[Electroman]

In a few years anything less than 400 miles EPA will not be the preferred choice.

 

[ZenRockGarden]

In a few years anything less than 400 miles EPA will not be the preferred choice.

It's reasonable to expect gradual increases in range for all types of packs as they refine the technology (and the cars themselves). MYLR has already seen iterative increases over the years from 316 to 326 to 330 - I'd expect that kind of pattern to continue, but not a leap to 400 suddenly.