What to expect from Tesla’s Battery Day

What to expect from Tesla’s Battery Day
CEO Elon Musk at a Tesla product event

Officially scheduled for September 22, 2020, Tesla’s Battery Day is one of the most awaited days of the year for the EV community.

However, Tesla postponed this event several times and now it’ll be harder to impress us, considering that Chinese companies already unveiled extremely important breakthroughs in battery technology, such as more energy-dense CTP (cell-to-pack) module-less battery packs, the comeback of the cobalt-free LFP (LiFePO4) chemistry to mainstream passenger electric cars or the imminent arrival of energy-dense cobalt-free LNMO batteries.

So what can Tesla unveil that represents a step forward to its current battery packs?

 

CTP (cell-to-pack) battery packs

BYD Blade battery with CTP technology

 

Adopting module-less battery packs is the most logic thing Tesla can do and Elon Musk already stated that using modules doesn’t make sense nowadays.

By adopting CTP battery packs Tesla actually takes two steps forward, because not only abandons modules, it also means that the automaker will replace thousands of tiny cylindrical cells with few long prismatic cells in a battery pack, making the process of assembling a lot simpler, faster and cheaper.

 

New battery chemistries

While Tesla’s electric cars made in the USA get NCA battery cells made by Panasonic, in China Tesla already uses different chemistries such as NCM 811 by LG Chem or cobalt-free LFP (LiFePO4) by CATL.

If Tesla wants production to surpass one million units per year, the battery chemistry of its entry-level trims needs to be cobalt-free, either LFP, LFMP (high-voltage version of LFP) or LNMO. Premium trim levels will probably remain with batteries that use more energy-dense and expensive NCA, NCM or NCMA chemistries.

 

Million-mile battery

While million-mile batteries already exist with current chemistries – they just need to have their maximum charging voltage limited by a good BMS (Battery Management System) -, being vocal about them is an important marketing strategy, especially since the first-generation Nissan LEAF gave a really bad reputation to EV batteries.

Advertising million-mile and cobalt-free EV batteries might be the best strategy to convince people that still think that electric vehicles aren’t sustainable products.

 

V2G (Vehicle-to-Grid)

Nissan LEAF with V2G capability

 

Having the ability to use your electric car as a portable battery can be extremely useful, especially in emergency situations. It’s an easy to implement technology, so I expect Tesla to make all its electric cars V2G compatible anytime soon.

However, V2G only makes sense for electric cars with extremely durable batteries, therefore it needs to be announced with million-mile batteries. Curiously, the Nissan LEAF with its fragile battery already supports this technology, which makes no sense to me…

 

 

Anyway, we still need to wait a few more days until we know for sure what Tesla will unveil. What do you expect from this event?

Pedro Lima

My interest in electric transportation is mostly political. I’m tired of coups and wars for oil. My expectation is that the adoption of electric transportation will be a factor for peace and democracy all over the world.
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Francesc
Francesc
2 months ago

Elon said ” it will blow your mind” … lets see what happens.

Neu7ral
Neu7ral
2 months ago

Any information on the rumored silicon nanowires technology?

Maximilian Holland
Maximilian Holland
2 months ago
Reply to  Neu7ral

Wake up sleepy – Musk already said this rumour was a mistake – like 2 weeks ago already.

Maximilian Holland
Maximilian Holland
2 months ago

I agree with this Pedro. LFP / LFMP will provide the bulk of Tesla’s packs for their highest volume EVs, and already give near to 450 km of range. Also LFP will dominate their stationary storage products.

I also think Tesla will talk more about their in-house battery R&D and pilot production line at Kato Road. I would guess that the focus there is mainly on NCx cathode cells, implementing the dry battery electrode technology, and the innovative (tabless) current-collection technology. These technologies could also be brought to LFP/LFMP – likely in manufacturing partnership with CATL.

Since the 2021 upgrade to the Porsche Taycan, and the Lucid Air, have both been recently announced and will both be ahead of Tesla’s existing flagship Model S on performance, and fitting the timing Musk announced late 2019, I expect they will finally start producing the Model S Plaid. Probably using their own in-house cells from Kato Road, which presumably have high energy density and decent peak c-rates.

More speculatively – it might be sensible to put a 50 kg (around 1 kWh) supercapacitor bank into the Plaid for battery/motor cooling benefits during hard track sessions. Repeated extreme acceleration and regen adds a lot of battery pack heat (and motor heat). A small supercap cache that shaves off 50% of that acceleration/regen task from the battery would make a huge different to pack temperature, and allow more cooling to go to motors and inverters. The feasibility of this is dependent on a heat tolerant supercap, since these would also get very hot during a track session, which can be pushed over a short (7.5 to 15 minute) track session without needing much active cooling.

These same cells will go into the Roadster, but it won’t make any sense for them to announce a date for the roadster (Osborne effect on Model S Plaid). They will also want to get real-world user data from the Plaid to make further improvements to the Roadster’s engineering before release.

Bringing the thermal management (heat pump & octovalve) from the Model Y to the Model 3 (this just normal Tesla steady improvement). A few other basic technology updates like this.

Likely some aesthetic refresh to the non-plaid Model S and Model X, as well as powertrain update (likely incremental, possibly using the new NCx cells in the performance Models).

Update to the Semi Truck information – probably announcing that ~600 miles range has been validated with the new NCx cells. Strategically pouring some cold water on the H2 FC hype of competitors.

A few other bits and pieces.

I totally agree that LFP is the real game changer on EV pricing and scalability. However, since it is not “sexy” I don’t think Tesla will talk about the technology much, but just emphasize the cost & supply reliability & scalability, and freeing up the NCx cells for Semi and other long range EVs.

Marcel
Marcel
2 months ago

Yeah, I think you’ve covered it here. Although I think there might be more emphasis on the in house Kato Road batteries. They might focus on planned production of the new batteries, so they could be talking about massive scale of production for cheaper batteries. I think that will be a big deal.

Andrés
Andrés
2 months ago

Sinceramente espero muy poco para ese día. Fuegos artificiales y mucho humo para que las acciones de Tesla y el bolsillo del multimillonario Elon suban sin parar. Es realmente patético la publicidad gratuita que se le esta haciendo a este sujeto y Tesla. Los medios no os dais cuenta “o no queréis daros cuenta” pero vuestra posición en todo esto es patética como poco.

Rodri
Rodri
2 months ago
Reply to  Andrés

What is it? Envy? You didn´t buy Tesla stock in time? What do you propose? Keep burning oil?

carlos
carlos
2 months ago
Reply to  Andrés

Yeah, Elon Musk. Tsk! What has he ever done for mankind?

Reminds me of Monty Python.
‘ All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us?’

Earl Colby Pottinger
Earl Colby Pottinger
2 months ago
Reply to  Andrés

Talk about your sour grapes.

Rodri
Rodri
2 months ago

So Elon said he would like Teslas to be cheaper so I expect some plan reveal about how are they going to enable it. Will they keep being a luxury brand or will they go mainstream?

PS. Apparently the German “study” that falsely claimed electric cars have more emissions over its lifetime than ICE made it to a Spanish school book used in high school:
https://twitter.com/alfredo_sanchiz/status/1304304598723813383

Famlin
Famlin
2 months ago
Reply to  Rodri

Even if they use 100% coal its still cleaner since electric vehicles have 50 km/l equivalent which means 1 liter of gasoline/petrol generates 8 KWh in power plant which can power the EV for 50 km. If you put 1 liter in ICE, it will go only 15 km. And pollution from coal is only 20% more than oil, but goes 200% + extra distance. Overall coal powered EV will emit 40% as much pollution as gasser.

Here is simple ex:
100 units of petrol powers vehicle for 100 km and emits 100 units of pollution
100 units of coal powers vehicle for 300 km and emits 120 units of pollution;
300 / 120 = 2.5 times the distance or inversely 40% of the pollution.

In reality, coal provided only 36,38% of worlds electricity in 2019. This keeps shrinking as solar/wind are grabbing bigger share. How long these phony media can spread lies. Even bp admitted that oil consumption has peaked in 2019.

Famlin
Famlin
2 months ago

I hope they reveal at least the battery price range like $120 – $140 / KWh since they are using NCA and NCM batteries.
Event starts at 13:30 PDT with earnings call, hopefully the battery part may start by 15:00 PDT, so we have 192 hours from now.

Barry
Barry
2 months ago

Will Tesla start offering ~800 to 1000 V battery architecture, say in the Model S Plaid, to enable smaller diameter and lighter copper wiring inside the car, and also increasing system efficiency thanks to less Joule heating (waste heat) in power electronics?

Famlin
Famlin
2 months ago

Cybertrk did excite all of us. The 5 pickup makers, the artists who did rendering (putting Tesla grill on Ram truck) were all shocked while the fans watched with greatest excitement.

Hoping for the same on Battery Day, 
battery technology, prices, new model reveal ???
lot of guesses.

Pedro Lima
Pedro Lima
2 months ago
Reply to  Famlin

The Cybertruck gets a meh from Europeans, it’s a product that only appeals to the USA market – and maybe Australia. What we would like to see is an affordable supermini (B-segment) made by Tesla.

Freddy
Freddy
2 months ago
Reply to  Pedro Lima

Ok… I have not seen a actual cybertruck (live in Portugal), but slightly shrinking it for the size of a standard european pickup truck (toyota hilux, etc…), at interesting price and with that closed back with the solar panels… I would totally buy it as a second car (I have 3500m2 home plot so it would be handy as a “small tractor” to carry stuff)… totally in to it for the 4×4 dual motor (not the 3 motor variant)… I never considered a ice pickup but I would do for the cybertruck…. it still has that “Tesla stretch factor”…at least for me…

Famlin
Famlin
2 months ago
Reply to  Freddy

Good thinking Freddy

I am wondering if they add another axle in the middle with a pair of wheels and make it a 6 wheeler, will it be used in farms as a tractor.
But farmers use the tractors only during the tilling, sowing and harvest days. Ideally an electric vehicle should be used 250 – 300 days / year to get the return on investment. Using it for 60 – 120 days / year may not be economical given the higher purchase price.

Whats your opinion?

Freddy
Freddy
2 months ago
Reply to  Famlin

I was not really thinking as a full working tractor as this would need like the transmission veins/shaft and hydraulics (this believe is more easy than the shaft) for essential tractor accessories… I was thinking more like a hauling farm transporter… as I do not have paved roads on the property, a 4×4 would be ideal and that bed also works for haulage of big volumes such as trunks, hay, and whatever needs transport…

Freddy
Freddy
2 months ago
Reply to  Freddy

It would replace my versatile ICE Renault Mégane Estate from 2000 which now has 360K Kms… which occasionally is used for transport large volumes but on roads only. It could be used combined with the leaf in the daily commute, so could charge both cars fully using solar 1 time every 2 days – the other day would take it to work…

Famlin
Famlin
2 months ago
Reply to  Pedro Lima

Shortly after cybertrk revel, elon said that a shorter version will be released which will be in size of ford ranger, jeep gladiator and this is still big for europeans.
So Elon said recently that there will be another smaller version for europeans which could be in same size as ford explorer.

Yes cybertrk combines the functionality of a
van: extra volumetric space and secure storage/transport.
pickup: easy loading and carrying tall things.
So cybertrk is a great new concept which should applied in multiple sizes for different customers.

I even tweeted a picture with 6 possible sizes to musk, tesla, but no response.

Marcel
Marcel
2 months ago

Pedro, have you seen the article on Electrek with a photo of a much larger cylindrical cell with a tabless current collector? Could be a key part of what they present at battery day.

Pedro Lima
Pedro Lima
2 months ago
Reply to  Marcel

Hi Marcel.

Yes, I did see it. If true it means that Tesla will keep using cylindrical cells.

Marcel
Marcel
2 months ago
Reply to  Pedro Lima

Yes they will if that’s an actual product. If true, this cell will probably offer less internal resistance, and better heat dissipation, as well as being more energy dense and cheaper than the 2170s. As well, they could build a pack with ~1000 cells instead of ~4000 cells, so the pack manufacturing process would also be easier and cheaper than the current cells.

Barry
Barry
2 months ago
Reply to  Marcel

I realize from a packaging point of view, the CTP ideal with rectangular cells seems the best, but the packed brick geometry may not be optimal for thermal durability. The cylinder is still a better shape for optimal heat transfer and minimal temperature gradients within the cell. I have read peer reviewed scientific papers that explain temperature gradients within cells is the primary cell killer, due to thermal stresses as well as high temperatures. Packed bricks may be fine for low performance packs with necessary power throttling, but for high performance packs, cylindrical cells may be the only way forward for now.

Marcel
Marcel
2 months ago
Reply to  Barry

Yes, I was talking about The large format cylinder with tables collector design, which should have significantly better heat transfer within the cell. As well, like the video Pedro posted shows, it’ll prevent heat and current channeling within the anode (or cathode, I cant remember)

Pedro Lima
Pedro Lima
2 months ago
Reply to  Marcel

This video is great in explaining some possible advantages of tabless electrodes.

https://www.youtube.com/watch?v=Rcw3vA0gAMs

I’m curious to see if Tesla can actually make a module-less battery pack with those cylindrical cells.

Marcel
Marcel
2 months ago
Reply to  Pedro Lima

haha, yes, I watched that video Just before I made my comment! it is very well done. Exciting stuff coming on the 22nd.

i suspect this new giant cell will be used in the semi and the cybertruck. I am very curious to see if they do also talk about LFP batteries in cheaper models as well.

Marcel
Marcel
2 months ago
Reply to  Pedro Lima

Oh yeah, I’m guessing they could make a module-less pack with these, just not in their current vehicles, since the cells are much taller.

i was also looking at the top of this cell in the photo, and it appears there’s an aluminum disk on the top, so I’m wondering if they’ve added a tabless collector on the top as well? Or maybe some sort of multi tab design, so the current doesn’t all have to move through one bottleneck. They’d have to add some kind of fuse to the cap though, but this would greatly reduce current and heat channeling in the electrode material.

Famlin
Famlin
2 months ago
Reply to  Pedro Lima

Is Tesla Model 3 MIC uses primatic cells or pouch cells. Do you expect all 3 types; prism, pouch & cylinder to continue or 1 of the 3 will take over.

Pedro Lima
Pedro Lima
2 months ago
Reply to  Famlin

Tesla Model 3 MIC uses prismatic battery cells from CATL.

I expect prismatic battery cells and CTP (cell-to-pack) module-less battery packs to become the norm for most automakers.

BYD Blade Battery is by far my favorite battery pack.

Marcel
Marcel
2 months ago
Reply to  Pedro Lima

Yes, the blade battery is very promising, but there was a twitter comment from Moneyball saying they were having trouble with production volume and venting issues. Hopefully they can work those out.

https://twitter.com/DKurac/status/1303643973395902464?s=20

Pajda
Pajda
2 months ago
Reply to  Marcel

I heard rumors about this specific Tesla format long time ago, so it seems to be true project. The cylindrical format have one big advantage that it does not need a solid module to prevent puffing. I was quite surprised how much single CATL VDA-PHEV2 “hard case” prismatic format cell puff up after 1000 cycles. So even CTP technology with prismatic cells, like BYD Blade must be somehow compressed in battery pack which I think makes difficult to replace single cell.

Cylindrical cells are also best suited for a flooded battery design. Where the cells with busbars are submerged in dielectric fluid. This approach not only makes TMS more effective but also acts as safety feature. But this technology needs hi-tech assembly line.

Marcel
Marcel
2 months ago
Reply to  Pajda

Interesting, thanks!

hawk
hawk
1 month ago

Hi Pedro Lima,
will you do a battery day follow-up and give us your thoughts on it?

Pedro Lima
Pedro Lima
1 month ago
Reply to  hawk

Hi Hawk.

I was disappointed with Tesla’s Battery Day because I was expecting Tesla to unveil a cobalt-free battery and give us some raw data about it.

I tried to write an article with my thoughts, but got frustrated because Tesla only gave us percentages to discuss, nothing solid such as Wh/kg, Wh/L or cost per kWh.

For the kind of articles I like to write we get more useful data from BYD or SVOLT.

Having this said, if Tesla improves production volumetric and speed efficiency as it proposes, it’ll be revolutionary.

In the long run it looks like Tesla might shift from being an automaker to a machine-maker and compete with KUKA Industrial Robots.

hawk
hawk
1 month ago
Reply to  Pedro Lima

They did announce cobalt free batteries, but unfortunately no details. Guess they don’t want the competition to know too much. I understand your frustration of not having solid values to do comparisons.

Elon did say the actual product will be the factories, not the cars. Mass manufacture is what’s actually difficult.

Pit
Pit
1 month ago
Reply to  Pedro Lima

Hi Pedro,
Model S plaid will have the new 4680 batteries and will be a 7-seater.

Do you think the (presumably) longer wheelbase came from the new battery modules?

Pedro Lima
Pedro Lima
1 month ago
Reply to  Pit

Hi Pit.

Sorry but I have no idea.