Technology, regulation and motivation

Samsung SDI 21700 battery cell specs

Our environment is constantly changing and to better adapt to it we must understand what’s happening. As Charles Darwin puts it, “it is not the strongest species that survive, nor the most intelligent, but the ones most responsive to change.”

The same principle applies to corporations, not every automaker will survive the transition from fossil fuels to electricity.


Let’s see where we are and where we are going.




While I prefer the simplicity of a battery pack made with fewer pouch or prismatic battery cells, I reckon that are still the tiny cylindrical battery cells that lead in terms of energy density and flexibility. The tiny cylindrical form allows Tesla/Panasonic to use the exact same cells to build battery packs in many shapes and forms for very different products – electric cars, powerwalls and powerpacks. Samsung SDI also has cylindrical battery cells that can be used in small battery packs for electric bicycles or big battery packs for electric cars.


Both groups, are moving from 18650 to 21700 battery cells. If you’re curious to know what the codes mean the figure below helps. The last digit is “0”, this means that the battery cell’s form is cylindrical, however Tesla from now on will remove this obvious reference and will call their new battery cells simply by their diameter and height (2170).


Samsung SDI batteries – 18650 vs 21700


Currently the best 21700 battery cell from Samsung SDI has the following characteristics:

  • Nominal capacity: 4.750 mAh
  • Nominal voltage: 3,6 V
  • Max. weight: 75 g
  • Current: 9 A
  • Cycle life: 80 % at 500 charge/discharge cycles
  • Dimension: 21×70 mm
  • Gravimetric and volumetric energy density: 228 Wh/kg and 705 Wh/L


Thanks to Jason Hughes we know that Tesla uses 8.256 cells per P100D battery pack, each with 102,4 kWh total capacity. This gives us 12,4 Wh per cell and an amazing volumetric energy density of 750 Wh/L – the same as every other 18650 cell with 3.500 mAh currently built by Sanyo/Pansonic, LG Chem or Samsung SDI.

If we want to have an educated guess about the characteristics of the new 2170 battery cells – currently on production at Tesla Gigafactory -, we need to recall that Tesla CTO J.B. Straubel said that the energy density is 30 % higher in Tesla Model 3 when compared to the current Tesla Model S. This would give us a volumetric energy density of 975 Wh/L and the 21700 battery cell’s nominal capacity would surpass 6 Ah.



Check the video below, especially from the 35 minute onward.



As a side note, I believe that the biggest battery capacity available for the Tesla Model 3 will be 85 kWh, while the Model S and X will get 130 kWh to differentiate themselves and don’t cannibalize sales. This is just my educated guess by looking to what’s possible with the energy density available.


However, Tesla isn’t the only company showing us what it’s possible with today’s technology. Kreisel Electric by using simple 18650 format battery cells – available since 2015 -, each with 3.500 mAh managed to make a 55,7 kWh battery pack for the Volkswagen e-Golf.


Volkswagen e-Golf with a 55,7 kWh Kreisel battery and 106 kW fast charging capability. Good for 435 km NEDC range


Kreisel Electric e-Golf battery specs


If this 55,7 kWh battery pack from Kreisel Electric already makes us cringe when we look to the new 35,8 kWh battery Volkswagen has reserved for the e-Golf, what would be your reaction if Kreisel Electric unveiled a battery pack built with the new Tesla/Panasonic 2170 cells? If these battery cells really have 30 % higher energy density, a 72,41 kWh for the Volkswagen e-Golf is already possible.


As you can see, the available technology isn’t what is delaying the mass production of electric cars.




While I think that regulation is important, it needs to be smart regulation, otherwise it can be counterproductive.

If given a choice, automakers or any other company that operates under Capitalism, always prefer to sell products with intrinsic planned obsolescence. This is why giving taxpayer’s money to buy electric cars doesn’t work, automakers will just increase the price and put the money incentive in their pockets, the end result is counterproductive. However, between selling electric cars or selling nothing at all, automakers will choose the first option. For this reason, Norway’s example is one to follow. If we want more electric cars, we need to make selling polluting cars harder, with higher direct sale taxes and more taxes applied to fossil fuels. There is no excuse to continue to allow selling polluting products when better alternatives exist – but are constantly undermined by the market forces that only care about profits.



Internal Combustion Engine (ICE) cars are only cheap to produce since they are subsidized by taxpayers. While automakers get all the profits, taxpayers have to support all the negative externalities, such as wars for oil or increasing healthcare costs due to pollution. As Noam Chomsky acknowledges, “a basic principle of modern state capitalism is that costs and risks are socialized to the extent possible, while profit is privatized.”


I don’t even think this should be a divisive topic between left and right, it’s just common sense – that unfortunately doesn’t exist in Donald Trump’s presidency. We need a carbon tax!




Automaker’s motivation to adopt electric powertrains will differ from automaker to automaker. Much more than the existing mediocre regulation, it’s Tesla that is going to push electric cars forward. Tesla Model 3 will not compete with other electric cars. It will position itself to be a much better alternative to BMW, Audi or Mercedes premium ICE cars. Luxury carmakers are definitely the ones who need to adopt electric powertrains sooner than any other else.

However, seeing is believing, and it isn’t until Tesla Model 3 is sold by the millions that legacy automakers will realize they are risking their existence because they didn’t adapt to change fast enough.

I’m confident that by 2020, every automaker will be in a race to go fully electric. Some will survive, others won’t.

I’m going to end this article with another quote, this time from Abraham Lincoln, he said that “the best way to predict your future is to create it.” This is exactly what Tesla is doing better than any other company. Most automakers are still in denial, trying to fight reality and losing precious resources while doing it.


What do you think? Which legacy automakers will better adapt to change? Which will prosper and which will go bankrupt? Is there a startup company which you think that will follow Tesla’s footsteps with success?

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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4 years ago

No se lo tome a mal pero es usted excesivamente optimista la nueva celda de Panasonic-Tesla sera equivalente a la samsung osea 4750 mah.

4 years ago
Reply to  Pedro Lima

Thats Wh/l, not /kg Pedro. Different parameter altogether. Currently we are ~250Wh/kg at the cell level.
That may be what is said below.

4 years ago

Tiene usted razón Pedro Lima. Hacer declaraciones de este tipo y con graficos de por medio implica mucha seguridad-responsabilidad y más si es la propia Tesla quien lo dice. Pero el tiempo me ha vuelto muy desconfiado Pedro Lima por que antes muchos han prometido lo mismo sin cumplirlo si no mire a Envia, Grabat Energy, Prietto Battery, Solid Energy etc…..Sinceramente si el Model 3 monta estas celdas de 5750-6000 mah y unos 300-350wh/kg seria toda una sorpresa para mi, más aún teniendo en cuenta que la mejor celda de este tipo es la samsung de 4750 mah 75 gramos y 228wh/kg. Que tenga un buen día Pedro Lima.