Tesla Battery Day will be ‘very insane’ here are my predictions

This Wednesday, 23rd of September at 6:30AM (AEST) is Tesla’s Battery Day. This event is technically a shareholders meeting, but will also be watched by analysts, media and the world, as Tesla speaks to their latest chemistry and technology breakthroughs in the battery space.

Tesla events are rare, but like Autonomy Day last April, these presentations help the market understand how millions of dollars in Tesla R&D efforts are returning value to the company. This helps us position Tesla relative to the rest of the market as announcements from the competition occur in the EV space.

What we know absolutely is very little, but through a combination of tweets from Elon Musk, leaks online and some fairly educated guesses, here’s what I think, is going to be announced at Battery Day, and the ramifications of making major announcements.

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New battery size / tech

Regardless of the design of a car, the number of over-the-air updates, or how sexy your mobile app is, none of that matters if you don’t have the core competencies down. Electric Vehicles rely ultimately on 2 things – the battery pack and electric motors. There are obviously secondary challenges systems like cooling, charging, etc, but the soul of an EV really starts with Batteries and Motors.

If a company wants to sell an EV, they really need to achieve a decent range for customers to even consider them as a viable option. Tesla vehicles already offer good range, a symptom of a right-sized battery, really efficient electric motors, along with intelligent battery management systems providing the right offset to the additional weight.

With the right electric powertrain, the body is also constructed with a sleek, aerodynamic design that also happens to be aesthetically-pleasing. This is complimented by flush door handles, well designed mirrors and wheels that are all focused on reducing drag on the vehicle, in-turn, delivering great range. Basically automakers are currently leveraging every trick they can to achieve acceptable range numbers.

But what if there was a better battery, one that had almost all upside and next to no downsides. This would come through amazing engineering and science efforts from the smartest minds at Tesla.

Today, the Model 3 SR+ is Tesla’s shortest range vehicle, at 460km (using the NEDC rating). The longest range car is the Model S LR at 713km (NEDC). In reality, the Model 3 gets around 400km of range, still very acceptable for Australian city and country driving. While there may still be instances where you may want longer range, the charging infrastructure is rapidly expanding and it won’t be long before we have charging options every 100-150km.

This means there’s likely not much of a market for Tesla to increase the range, if it cost more to achieve that. Instead, the overall goal should be to make Tesla vehicles more affordable, to enable more people to go EV, reduce emissions and achieve Tesla’s goal of accelerating the world’s transition to sustainable energy.

So if a cheaper car, that can go further, for longer, is really what we’re after, it makes sense that Tesla focuses on reducing the cost of the single most expensive component, the battery.

Elon’s Tweets

Often Elon’s Tweets reveal more than we first realise. Here’s a quick sample of Musk’s posts relating to Battery Day.

Electrek leak

Last week, Fred over at Electrek, received 2 photos from an anonymous source, which were then later independently verified to be the new and improved, Tesla battery cells. The new size is estimated to be around 4575, compared to the 2170 found in the Model 3 and Y and the earlier designed Model S and Model X that both use an 1865 cell. This means the new cell would feature a 5x growth in volume, as compared to the 2170. That could see an 80% reduction in the number of individual battery cells in the cars.

These photos came with no detail about the internal chemistry changes, but did show off the new, massive size increase. This cell size increase is important for a number of reasons.

Firstly, if Tesla is able to produce the same (or similar) energy from fewer cells per vehicles, that means each vehicle consumes less battery cells. Now for the million dollar question, if they need half the number of cells in each car, does the production time to make each cell, take less than double the time. If it took double, there’d be no net benefit, in terms of production speed.

Here’s where things get really interesting. If Tesla could make the new larger cell in the same time as the current batteries, their current battery-constrained challenge could finally be alleviated. This would result in more cars being made, more people driving EVs and more profit for Tesla and therefore value for Shareholders.

Secondly, the construction of the new batteries could include a number of significant improvements over what we have today.

Dry battery electrode (Maxwell acquisition)

Back in mid 2019, Tesla acquired Maxwell Technologies. It’s likely the fruits of that acquisition, will be shown off at this week’s Battery Day event. Tesla doesn’t acquire companies very often, so for them to buy Maxwell, then remove content published publicly, they obviously seen something they liked, that would help them with their mission.

This document released in May 2019 detailed that Maxwell’s dry battery electrode technology.

Packless design

Right now, Tesla buys battery cells, then combines them into modules, in the case of the Model 3 and Model Y, there are 4 modules which are then connected by a battery controller. Each module requires thermal management, so cooling chambers are run between each cell.

It’s possible that Tesla will now move to a packless (or module-less) design. This could use the bottom floor of the Tesla as a base, then the battery cells would be loaded directly. Instead of cooling the cells from the sides (more difficult with larger cell diameters, they could be moving to a technique that would see the heat distributed to the top (maybe top and bottom) of the battery to be drawn away with a new, more efficient cooling system.


We often talk about lithium-ion as all one battery type, but in reality, there’s actually multiple compositions of batteries. The following table from Battery University, details the different properties across a varieties of chemistry under the Lithium banner.

One of the most challenging materials is Cobalt. It’s difficult because it’s rare, with around half of the world’s deposits in the Republic of the Congo. It’s a nasty mining process to retrieve and process Cobalt and unfortunately the mineral has been tarnished by a number of instances of child-labour being used. Essentially the world would be better off if we could make batteries without it.

It is believed that Tesla will reveal a Cobalt-free chemistry this week.

SpecificationsLi-cobaltLi-manganeseLi-phosphateNMC 1
Charge limit4.20V4.20V3.60V4.20V
Cycle life 2500500–1,0001,000–2,0001,000–2,000
Operating temperatureAverageAverageGoodGood
Specific energy150–190Wh/kg100–135Wh/kg90–120Wh/kg140Wh/kg
Specific power1C10C, 40C pulse35C continuous10C
SafetyAverage. Requires protection circuit and cell balancing of multi cell pack. Requirements for small formats with 1 or 2 cells can be relaxed Very good, needs cell balancing and V protectionGood, needs cell balancing and voltage protection
Thermal runaway 3150°C (302°F)250°C (482°F)270°C (518°F)210°C (410°F)
CostRaw material highMaterial 30% less than cobaltHighHigh
In use since1994200219992003
Researchers, manufacturersSony, Sanyo, FDK, SaftNEC, Samsung, HitachiUT, QH, MIT A123, ValenceSony, Sanyo, Nissan Motor
NotesVery high specific energy, limited power; for cell phones, laptopsHigh power, average to high specific energy, power tools, medical, EVsHigh power, average specific energy, higher self-discharge than other Li-ionVery high specific energy, high power; tools, medical, EVs

Tabless electrode

This one is a really complex topic and one YouTube channel ‘The Limiting Factor’ does a great job of breaking down. I’d strongly recommend you watch the clip below on the ramifications of the new cell.

Which vehicles would get the battery first?

Imagine Tesla has these amazing new batteries with loads of upside and virtually no downsides, your next question is how many can they make and which products are we likely to see them in first. While it’d be tempting to do a 100% transition to the next battery tech, the reality is, we’re likely to see a phased implementation over the coming months and years.

This raises the question of how Tesla avoids the Osborne-effect. Obviously if the new battery tech is coming, future customers will want to cancel existing orders, to ensure they get one of the new cars. Given the current demand is outstripping supply, this places an even great

  • Obvious applications are the Tesla Semi (long distance, changes the business economics)
  • Roadster (already claimed 1000km+ range), this new battery could achieve that
  • Cybertruck – help icnrease tow distances
  • Model X / Model S – faster charger times (V3 superchargers may be able to go higher than 250kW.. 350kW??
  • Plad only?
  • Production challenges adding it to Model 3 and Model Y lines (production downtime)

Who would make them?

It is possible that Tesla themselves will enter the battery production game, which would enable the company to keep more profit and achieve a faster return on the R&D spend.

Given the volume of batteries required, it’s possible they could ask partners Panasonic and CATL to manufacture the new batteries, to the new spec to help increase the number of new batteries (with all the benefits), as soon as possible. While Tesla has existing battery production contracts in place, it’s not clear if they’d be locked into the same technology over the life of their contract.

It’s possible Tesla thought far enough ahead to include clauses like that permit Tesla to shift battery purchases to use the best technology where available.

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Industry-wide ramifications?

After watching the battery technology rapidly evolve over the past decade, it’s commonly understood that we were looking at a timeline around 2023/2024, where EVs would be on-par and even be cheaper than an equivalent ICE vehicle.

If Tesla does announce the expected improvements to battery technology that could see cars become cheaper, go further and have longer lives, that changes the game significantly. Depending on how fast they can ramp up production of the new cells, we may see price parity reached, years earlier.

This milestone is particularly important, as the company’s mission of transitioning the world to sustainable energy, could be rapidly accelerated by cars that are better in every way than ICE vehicles. At that point you’d really need to be suffering from a severe case of nostalgia to buy anything else than and EV.

Probably the most interesting aspect for me will be the way Tesla distributes any potential savings in the cost of the battery and therefore the overall car.

If the price of a Model 3 (Tesla’s cheapest car), was to drop by $5k thanks to battery tech,  then also reduce again thanks to a move in production location (reduced shipping cost), this would definitely help land the car in the price range of more customers, increasing sales.

One thing is for sure, it won’t be boring.

I’ll be up early on Wednesday morning for Battery Day, so expect plenty of news, right here on techAU.

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Jason Cartwright
Jason Cartwrighthttp://techau.com.au/author/jason/
Creator of techAU, Jason has spent the dozen+ years covering technology in Australia and around the world. Bringing a background in multimedia and passion for technology to the job, Cartwright delivers detailed product reviews, event coverage and industry news on a daily basis. Disclaimer: Tesla Shareholder from 20/01/2021


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