Tesla Inc (TSLA)

[JohnCM]

Tesla superchargers and graphene batteries

BY PEDRO LIMA · PUBLISHED DECEMBER 27, 2016 · UPDATED MARCH 29, 2017

It seems that 350 kW aren’t enough for Elon Musk.
Fred Lambert from Electrek recently exchanged two tweets with Tesla’s CEO, Elon Musk, that generated much enthusiasm about the third generation superchargers.

In the below we have the two tweets.

Fred Lambert
@FredericLambert
@elonmusk Any update on plan to install solar arrays at Supercharger stations?

Elon Musk
@elonmusk
There are some installed already, but full rollout really needs Supercharger V3 and Powerpack V2, plus SolarCity. Pieces now in place.
11:13 AM - 24 Dec 2016

24 Dec
Fred Lambert
@FredericLambert
Replying to @elonmusk
Supercharger V3? Now I'm curious. What power out are we talking about? 350 kW?

Elon Musk
@elonmusk
A mere 350 kW ... what are you referring to, a children's toy?
11:18 AM - 24 Dec 2016

While most got excited about the faster charge, my immediate reaction was: “finally they are getting graphene batteries!”
In his articles, Fred Lambert noted that to get the full CARB ZEV credits, zero-emission vehicles are required to have over 300 miles EPA range and the capability to recharge from 0 to 95 % in 15 minutes or less. While the 100 kWh battery is enough to give the Tesla Model S P100D a 315 miles EPA range, it doesn’t charge fast enough to get 9 credits.

The soon to be made at the Tesla Gigafactory, 2170 cylindrical battery cells are reported to be 30 % more energy dense when compared to the 18650 used now. The kWh cost will be roughly 30 % less, since the same raw materials will store 30 % more energy.

A 130 kWh battery needs roughly 500 kW power to fulfill the CARB’s charge time requirements to get the 9 ZEV credits. But more important is what kind of battery can be recharged at 4 C-rate?

Currently there are some LiFePO4 and LTO batteries that can handle 4 or even more C-rates, but their energy density isn’t great. To get high energy density and high charge/discharge C-rates Tesla needs to replace the mixed graphite-silicon anode with graphene-silicon and can keep using NCA as cathode.

When compared to graphite, the extraordinarily higher electron mobility of graphene contributes for a lower internal resistance, which not only enables higher charge/discharge rates, but also keeps the temperature lower and increases the lifespan.

But where are we now? When can we get graphene batteries?
Well, they’re here already, for quite some time…

Besides Turnigy, there are other battery cell makers, for example the Chinese Westart company is already selling graphene batteries with good reviews from the Endless-sphere community.

More important is that Henrik Fisker, promised a 400 mile range electric car on graphene nanotech, the Fisker EMotion that will be unveiled next year. Graphene batteries aren’t sci-fi anymore.

Until recently, mass producing graphene was a problem, but it isn’t anymore. In the video below, Robert Murray Smith show us how to mass produce graphene from graphite with a simple and cheap method.

Robert Murray Smith is a great Science Communicator, he’s the Carl Sagan of battery technology, if you’re interested in the subject you should check out his YouTube channel.

We still don’t know if the first generation of Tesla/Panasonic 2170 cylindrical battery cells will use graphene, but I do suspect that Tesla have been quietly working on graphene since 2014, as thisChinese magazine suggested back then.

I’m sure that Elon Musk doesn’t underestimate Henrik Fisker and his promises about the upcoming graphene battery.

What do you think? Will Tesla introduce graphene batteries next year, or it’s more probable to be delayed until the Gigafactory reaches full capacity?