Tesla Air? Elon Musk Hints Tesla Could Mass Produce 400 Wh/kg Batteries In 3–4 Years

By Johnna Crider and Zach Shahan

Elon Musk suggested on Twitter last night that Tesla may be able to mass produce batteries with 50% more energy density in three to four years, which could possibly enable electric airplanes. Notably, Elon Musk and fellow Tesla cofounder and longtime CTO JB Straubel actually first met over lunch because of their mutual interest in making electric airplanes. They determined the energy density of batteries wasn’t yet close enough to make that practical, but that they could get into the electric car business.

The comments came as anticipation continues to mount for Tesla’s Battery Day event, where the company plans to showcase battery improvements and plans and/or battery production improvements and plans.

In response to a Twitter thread by Ark Invest’s Sam Korus, Elon tweeted, “400 Wh/kg *with* high cycle life, produced in volume (not just a lab) is not far. Probably 3 to 4 years.”

Researches say that the energy density of Panasonic’s 2170 batteries used in Tesla’s Model 3 was around 250 Wh/kg in late 2018, and more recent estimates put it at around 260 Wh/kg. So, 400 Wh/kg would be approximately a 50% jump in Tesla battery energy density, if those estimates are right.

Elon Musk has said on multiple occasions that the energy density of batteries needs to improve to over 400 Wh/kg for viable commercial electric flight. Based on Elon’s comments last night, this threshold could be achieved within the next 5 years. Remember, Elon Musk builds rockets — so he knows what he’s talking about here. 

There is much expectation that Tesla will unveil a “breakthrough” battery technology at Battery Day on September 22. Notably, Panasonic told Reuters that it plans to boost the energy density of its original 2170 battery cells that it supplies to Tesla by 20% in 5 years. That’s not close to the ~50% improvement implied above. However, that could mean that Tesla expects to reach this achievement on its own.

Environmental Impact of An All-Electric Airplane

Greenhouse gases from the aviation sector are a huge contributor to global warming, the Center for Biological Diversity reminds us. If this sector was a country, it would be the 6th highest emitting country — between Japan and Germany — in the world. And left unchecked, this sector will generate around 43 metric gigatons of Co₂ through 2050. 

This is almost 5% of the global emissions that are allowed if we want to keep global warming below 1.5 degrees Celsius. Here in the US, the aviation industry is one of the fastest-growing sources of emissions. Since 1990, emissions from domestic aviation have increased by 17% and account for 9% of the US transportation sector’s greenhouse gas emissions. Also pointed out in this study was that flights that depart from airports in the US and our territories create almost one-quarter of global passenger transport-related carbon emissions. The majority come from domestic flights. 

Electric vehicles are a key solution for climate change. While we have been focusing on electrifying cars, we can do this with aviation and shipping eventually as well, and need to. That will make the air cleaner and more breathable, while also protecting our climate. Air pollution contributes to a lot of respiratory and cardiovascular diseases, and is something we just accept even though, increasingly, we don’t need to.

If Tesla or other companies are able to bring the humble battery to 400 Wh/kg, how long until you and I are flying on an electric airplane?