🔋Tesla: One design tweak could boost acceleration and recharge speed

Musk Reads+ 68

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Tesla stock meets an uptick...

  • Tesla’s closing stock price lifted to $649 per share on July 22. The company has a total market valuation of $616 billion

  • The contiguous United States generated 14 percent of its electricity from solar, wind, and hydroelectric power on July 21.  Sources like solar roofs are excluded from the tally. A further 68 percent came from natural gas, coal, and petroleum.

  • SpaceX has now launched 132 missions to space.

  • There are seven people in space right now and zero people on Mars.

...while Musk is all-in on li-ion:

Tesla is not going after ultracapacitors, an exotic technology that could boost charge times and car acceleration. 

The electric car firm purchased energy storage firm Maxwell Technologies for $218 million in February 2019. The initial purchase excited fans as Maxwell was working on unique technologies like ultracapacitors and dry electrodes.

So why the sale to California-based UCAP Power? Musk explained on Twitter Wednesday why Tesla kept the intellectual property around dry electrodes while it decided to sell the ultracapacitor areas:

“Ironic indeed, as I was at one point going to do my Ph.D. at Stanford on high energy density capacitors for use in electric vehicles. But lithium-ion has it covered. Even with no advances in lithium-ion technology, it’s possible to transition Earth to sustainable energy.”

Musk also added further detail around dry electrodes:

“​​Dry electrode is a key piece (one of many pieces) of the puzzle for lowering the cost of lithium batteries. That said, it has required an *immense* amount of engineering to take Maxwell’s proof-of-concept to high-quality, volume production & we’re still not quite done.”

Tesla explained in September 2020 that using dry electrodes in its new battery design means 10 times less energy and 10 times smaller footprint for battery production lines. Unlike the wet electrode process, where a slurry is coated onto foil and heated, the dry process skips the whole heating step — which is more complicated than it sounds.

But what about ultracapacitors? Evé Wheeler Jones, a researcher at the University of Warwick, explained in June 2019 that these charge and discharge just like batteries, but they have higher power output and shorter charge times

On the downside, they also have a lower energy density, or energy per kilogram, compared to batteries. A higher density can enable more ambitious vehicles like an electric jet.

A team at University College London in February 2020 demonstrated a bendy supercapacitor made from graphene. The study’s lead author, Zhuangnan Li, tells Inverse that he agrees with Musk that lithium-ion is not about to be replaced.

“I agree (with) the point that a supercapacitor is not very possible to replace batteries as a sole energy supply for [EVs] due to the totally different working mechanism nature of these two systems,” Li says. “Supercapacitors will need to work combined with batteries and function as a booster or accelerator in the energy storage system while batteries work as charge reservoirs.”

Combining the two, Li says, would enable much faster acceleration boosts. It could also enable much speedier recharge speeds.

“All these merits can be achieved by a combination of supercapacitors and lithium-ion, but it’s not easy for the lithium-ion systems at the current stage,” Li says.

While supercapacitors could encourage more people to transition to electric vehicles, it seems the lithium-ion battery is here to stay either way.


This week in Musk history… 

  • On July 20, 2016, Elon Musk published the second Tesla “master plan,” entitled “Master Plan, Part Deux.” It included goals to create solar roofs, self-driving vehicles, and the opinion that “starting a car company is idiotic, and an electric car company is idiocy squared.”

  • A year later, on July 18, 2017, founder Peter Rive left SolarCity, Tesla’s then-new, $2.6 billion purchase. In an internal letter before his departure, Rive wrote he wasn’t worried about the future of SolarCity since, outside of Tesla, “there is no other company that can be more impactful in our fight against climate change.”  

...and the near future


Photo of the week

On July 19, SpaceX shared this stunning photo of Starship’s Super Heavy booster blazing, taken during Monday night’s static fire test. This test was key in confirming Starship’s structural integrity ahead of its 2021 orbital launch, and as the contained squall of fire and smoke suggests, it went well. 

Got a photo or video you'd like to see featured? Send it to muskreads@inverse.com!


Musk Reads mailroom: Can I trade in my Tesla battery?

Donald Peters writes:

I own a 2018 S75D and can charge it to about 240 miles. I’m just wondering if Tesla is considering or would consider a “trade in plan” for existing owners wishing to upgrade their batteries. Do you know of any such plan or possibility?

Hi Donald, thank you for this question! I have good news and bad news. 

The good news is that Tesla definitely has given a lot of thought to batteries. Let’s talk about battery trade-ins, battery swapping, and car trade-ins.

If you’re looking to upgrade your Tesla’s battery, different Tesla models use slightly different batteries, so a more recent battery might not fit in your vehicle. According to this InsideEVs article about upgrading your Model S battery, an upgrade would require “structural reinforcements that make the upgrade financially prohibitive.” Although you can, as I’m sure you know, replace a degraded battery for a somewhat hefty fee, you unfortunately cannot upgrade (unless you’d like to DIY!)

 As far as swapping goes, on June 21, 2013, Tesla held an entire event to announce their Model S swap program. At the time, Tesla said that the Model S’s battery swap capability was created to reach full battery charge “in less than half the time it takes to refill a gas tank, [offering] Model S drivers another even faster option when recharging while driving long distances.” The bad news is that the program was discontinued in 2015 after barely any Model S owners chose to swap instead of Supercharge.

Although battery swapping ended up being unpopular with EV users in the U.S., it’s a favorite method of recharging in places like China. Just this month the Chinese EV manufacturing company and Tesla rival Nio announced plans to create 4,000 battery swapping stations throughout the world by 2025, so you never know, maybe it will catch on here and Tesla will get back in the game. Until then, Tesla is sticking with whole-car trade-ins, which might be of interest to you if you’re primarily after a better battery, but, naturally, these trade-ins are nowhere as economically or environmentally friendly as a hypothetical battery upgrade.   

According to the Tesla site, it will allow you to put the cost of almost every type of vehicle, gas and electric, towards a new or used Tesla. The site also features a helpful calculator that estimates the trade-in value of your exact vehicle. According to this forum thread from 2018, experiences with Tesla’s trade-in program have been mixed, with some people undergoing a seamless process and others getting lowballed until their Tesla representative matched a higher offer. 

The last Tesla officially spoke about battery swapping was this year, in March, when they claimed Tesla was not interested in reentering battery swapping since the whole thing was “riddled with problems and not suitable for wide-scale use.” They issued the denial despite Chinese reports that Tesla China registered a new business for “sales of battery swap facilities.” So, like all things Tesla, time will tell how true that is.  


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The ultra-fine print 

This is Musk Reads+ #68, a new subscriber-only newsletter about the world of the futurist and entrepreneur Elon Musk. This was written by Mike Brown, an innovation reporter for Inverse, and Ashley Bardhan, assistant to Musk Reads.

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