Tesla Battery Day 2020
Tesla has just sent (again) a rocket in the Automotive Industry. Elon Musk has clearly set up his objectives to reduce Battery cost and to propose more affordable electric vehicles to accelerate emobility.
If you think, just as I thought, that “Battery day” just deals with Battery technologies, you are going to be surprised by Tesla’s presentation showing so many interesting things on their EV technologies, manufacturing optimisation, recycling, local supplying, sustainability, etc.
Elon Musk did not only convince his investors why he is so much in advanced compared to any OEM in the world when talking about EVs but he also highlighted a great innovation culture only possible by employing people with different backgrounds and mindset.
At the end of this 2h presentation, Tesla concluded with astonishing numbers:
54% increase in EV range
56% reduction in Battery price
69% reduction in the needed investment per GWh
How is that possible? Tesla’s strategy is based on 5 technologies all aiming at accelerating battery production or at maximising the battery usage in the vehicle. This strategy consists of:
New Battery Cell design
Rethinking the Cell factory process
New Silicon Anode material
New Cathode material Cobalt-free
New Integration of the battery in the vehicle structure
1- New Tesla Battery Cell Design
Fig. 1- New Tesla Battery Cell Design (tab-less). Left: the structure is not anymore composed of a single sheet rolls over itself but multiple structures organised in a concentric pattern; Right: characteristic of the resulting cells (more compactness resulting is range extension). Image credit: Tesla
Conventional cell designs are bounded by the amount of thin material sheet you are able to roll over itself. The more rolling sheets over a given volume, the more capacity. In order to get free from this constrain, Tesla has developed a new cell design, called “Tab-less”. This new structure is still based on a rolled jelly roll but it has tabs along the whole length of the electrode, not just at the centre. From the visual (Fig. 1) it looks like a sort of “patchwork of crumbles” of individual cells that can be connected to multiple neighbours allowing electrons to move faster. It results in:
5 times the Energy of conventional cells
6 times more power
16% range increase
Cell price reduction by14% ($/kWh)
2- Cell Factory Process Optimisation
Fig. 2- Illustration of Tesla cell manufacturing and the testing battery cells. Image credit: Tesla
I was astonished to see how Elon’s tackled explanation on industry / factory process which is normally a very boring subject. Thanks to a nice analogy with glass-bottle factories, Elon explained that Battery factories efficiency were up-to-now very unmatured compared to other industries in terms of optimisation and rentability (Elon even joked about his own factories). By analysing their own time-consuming processes, Tesla came up with a solution to accelerate their cell manufacturing by introducing a concept a “continuous motion assembly” and by improving factory space utilisation.
In particular, there is a step called “wet process” which is very long. Tesla’s Engineers have developed instead a new dry coating process (powder into film) which would result in:
10 times footprint reduction
10 times energy reduction
Accelerate the line production by 7 times
By improving efficiency of battery production, Tesla claims they would achieve 3 TWh production by 2030 and reduce battery cost by 18% (in $/kWh)
Nevertheless, Elon has been a little bit cautious on this point saying the process is still under final validation and is not 100% ready for in-line production.
3- Tesla Silicon Anode
FIg. 3- Usual Silicon usage results in bursting of silicon particles resulting in their isolation and loss of efficiency. Image credit: Tesla
Silicon is a very common component on Earth and is already used in small amount in Batteries. Nevertheless, its usage is limited due to particle expansion volume when charging because this expansion tends to isolate the particles (and so reduces their chemical efficiency)
Elon explained that instead of working around a way to reduce this expansion, Tesla researchers came with the idea to use this property in their design instead.
The solution is to use large raw particle of silicon, stabilise them on the surface thanks to elastic ion-conducting coating. This approach would rather simplify its structure and its manufacturing.
This technology would allow, according to Tesla, to increase battery EV range by 20% et to reduce battery cost by further 5% (in $/kWh)
4- Cathode Cobalt-free
Fig. 4- Traditional Cathode process according to Tesla. The result is limited cathode-usable-products as well as a large amount of wasted water. Tesla’s new approach will allow to increase the portion of useful cathode material while completely eliminating water waste. Image credit: Tesla
Tesla wants to maximise the usage of Nickel but to remove Cobalt (this would need some novel coating and additional dopants). Thanks to some “new Cathode manufacturing processes”, Tesla claims that they could become zero water-waste on the cathode production.
The strategy would be to use (1) iron medium range; (2) Nickel + Manganese medium/intermediate; (3) High Nickel content for long range applications (Tesla truck)
Tesla strategy would be to develop their own cathode facilities which would allow them to control their cathode supply chain, manufacturing process, footprint, etc.
Elon also mentioned that Lithium could be completely sourced in USA by exploiting the untapped Lithium in Clay.
By doing so, Tesla would be able to completely source their cathode material from a local supply chain.
Elon also presented an option to completely recycle Tesla’s battery (remove 3rd party) for sourcing Lithium and other metals adding value in terms of sustainability.
All together, the cathode manufacturing processes would reduce battery price by again another 12%.
5- Battery Integration in the Vehicle Structure
Fig. 5- Tesla’s casing for Battery would become completely integrated within the vehicle structure removing the need for additional inter-cells and inter-modules inserts. Left: Tesla vehicle structure. Right: floor space reduction. Image credit: Tesla
This has been for me the most interesting part of this presentation highlighting to which extend Tesla is THE world leader in EV concept.
The idea is to completely change the battery casing for the vehicle merging the battery organisation and a part of the vehicle structure. To illustrate, Elon explained how planes use fuel tank integrated inside the wings (in a sense fuel tanks in the shape of plane’s wings). The objective would be to do the same here: completely embed the chassis of the vehicle around the battery instead of integrated a battery inside a constrained vehicle structure. For this, Tesla’s Engineers have developed a proper new alloy that do not need heat threating or coating. The main structure would consist in a single piece high pressure die cast aluminium reducing the weight by 10%.
This technology results in 35% reduction in floorspace. Elon insisted on this technology as a key point forfeiture EVs. Tesla said this technology does not only give rise to a better product but also allows massive simplification (and so cost reduction) in the vehicle manufacturing process.
It reduces the battery price to further 7% reduction in cost
Conclusion
Fig. 6 - Overview of Tesla’s strategy on Battery Day technologies. Left: range increase; middle: Battery cost reduction; Right: investment saving on the GWh deployment. Image credit: Tesla
Tesla and Elon Musk’s objective are clear:
Build a Terawatt-hour scale Battery production
Produce more affordable Cells and electric vehicles
The plan? Halve the Battery cost per kWh thanks to 5 key technologies: (1) New Cells; (2) Manufacturing optimisation; (3) Silicon Anode; (4) New Cathode manufacturing Cobalt-free; (5) innovative battery integration in the vehicle structure.
All together, these technologies will give Tesla:
54% extra range for Tesla’s car
56% reduction in Battery price in $/Wh
69% investment reduction in terms of GWh
These 5 key innovations highlight Tesla leadership not only in Batteries and in EV know-how but also in terms of supply-chain, manufacturing process, etc. That seems so far from any consideration at most of OEMs. Good luck to keep on track!
