Sustainable Million-Mile Battery Bet Pays Off For Mercedes-Benz

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Mercedes-Benz put up a 3% stake in the EV battery cell manufacturer Farasis Energy all the way back in 2020, working the sustainability angle as well as performance. Now all that hard work is beginning to pay off. Farasis has just announced the results of an accelerated testing schedule, leading the company to claim that a battery pack deploying its cells will last 1 million miles, while ending up with 70% capacity after 15 years. Take that, haters.

The Million-Mile EV Battery Of The Future Is Coming…

It’s no secret that an EV battery can last far longer than some industry observers anticipated. CleanTechnica’s Jake Richardson recently took note of EVs still driving on their original batteries well over 200,000 miles and more, putting to bed the notion that EV batteries only last a couple of years before going kaput. Besides, federal law requires manufacturers to provide a warranty of at least 8 years or 100,000 miles on an EV battery.

The sticky wicket is calendric degradation, meaning that rechargeable batteries lose capacity over time. Conventional lithium-ion batteries are not the only ones to experience that problem. Researchers are also studying calendar aging in new lithium-metal and silicon EV batteries.

…And It Will Be More Sustainable, Too

With that in mind, let’s take a look back to 2020, when Mercedes-Benz acquired a stake in Farasis. It was more than a stake. The new agreement builds on a previous  relationship established in 2019, when China-based Farasis set up a subsidiary in Germany. The 2019 agreement reflects Mercedes’s focus on decarbonizing its supply chain as well as its own operations, requiring Farasis to use wind, solar, hydropower or other renewable resources to manufacture its battery cells in China.

Mercedes describes the 2020 contract as a “far-reaching strategic partnership” that represents another key step in the company’s carbon-neutral goal.

“The technological focus is on significant increases in range through advances in energy density and the reduction of charging times,” Mercedes explained, noting that the partnership cements a reliable EV battery cell supply chain while providing financial support for Farasis to build a factory in Germany.

How Sustainable Is A Million-Mile EV Battery?

As of 2020, the plan also included constructing another EV battery plant in the US. A map on the company’s website indicates somewhere in the US Southeast along the Gulf of Mexico, which is not a shocker to those following the rise of the electric vehicle industry in politically conservative states.

If and when Farasis gets around to building it, the new US factory will probably churn out the company’s P75 and P73 NCM  (lithium nickel-cobalt-manganese) battery cells, which the company unveiled last weekend, on July 20.

“Achieving a million-mile battery requires cycling the cell over 5000 times, a process that takes 24 to 36 months of accelerated testing,” Faraisis explained.

“These cells, developed since 2018, have undergone extensive testing and analysis, leading our engineers to confidently assert that battery packs using these cells can last a million miles over 15 years while retaining over 70% of their capacity,” the company emphasized.

The tests included a temperature range of 25-35 degrees centigrade, to account for markets in the coastal US as well as Europe and China. “Farasis Energy’s testing incorporated strenuous usage scenarios, including fast charging (equivalent to charging a battery from 10% to 80% in around 20 minutes for P75 and around 30 minutes for P73) and a high depth of discharge of 90% and above,” the company added for good measure.

As for sustainability, that depends. Decarbonizing factories in the EV supply chain is an important first step, but the the use of cobalt in batteries has already raised red flags among auto makers. On its part, Mercedes is tweaking its cobalt supply chain to ensure that it includes only audited and certified mines, regardless of the country of origin. The policy applies to lithium mines as well.

The longer lifespan of an EV battery can also help contribute to sustainability. Re-purposing an older EV battery for stationary storage can also extend the lifespan, and and battery recycling can help reduce the pressure to produce virgin materials.

Still, the supply chain issue is one that will continue to linger over the auto industry.

Secrets Of A Million-Mile EV Battery

As for exactly what factors go into the development of a million-mile EV battery, Farasis attributes that to charging strategies as well as materials. “The separators are coated with semi-solid gel to reduce the amount of electrolyte while ensuring excellent ion conductivity and chemical stability,” the company explains, adding that the “charging strategy is optimized to reduce lithium plating and heat generation, effectively suppressing the side reactions that cause capacity loss.”

To the extent that fire risk management is a key part of the lifecycle plan, the company is not shy about broadcasting its strategy. On June 6, Farasis issued a press statement detailing how it prevents thermal propagation in lithium-ion batteries, meaning the spread of overheating conditions from one EV battery cell to another.

Among other safety mechanisms, Farasis relies on a “flipped pack” design that positions the cooling plate on the upper side of the battery pack, where it is protected from stones and other random objects. “In the event of a [thermal runaway], the cell can be vented downwards towards the road, thus protecting the vehicle’s occupants,” the company notes.

Nobody Expects…Battery Swapping!

Critics of electric vehicles have been casting the fire safety stone, but a more fact-based picture is emerging as more data becomes available. Farasis cites the US firm AutoinsuranceEZ, for example, which calculates that 1.53% of gasmobiles will experience a fire over their life, but only 0.025% of electric cars will.

Advanced thermal management strategies will help reduce that number even farther, as will new solid state EV battery technologies and new EV battery formulas, including sodium-ion batteries.

Another factor is the growing use of EV battery swapping services, which helps to ensure that batteries are properly charged and maintained. Previous attempts at battery swapping in the early 2000s failed to gain traction, but in recent years the battery swapping field has gained some momentum, especially in the area of two-wheeled EVs.

Farasis is taking both the sodium-ion and the battery swapping angles in hand. On February 13, the company included new battery-swapping partnerships on its to-do list in support of its newly launched sodium-ion battery. The company outlined its plans with the unveiling of the tiny new JMEV EV3 (Youth Edition) city car in China, which it billed as the first electric vehicle to sport its new sodium-ion battery.

“The battery pack complies with the no thermal runaway (NO TP) standard,” Farasis noted.

The company also plans to introduce more powerful versions of the sodium-ion EV battery between this year and 2026, so hold on to your hats.

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Image (screenshot): A million-mile EV battery is one step closer to your new electric car, and Mercedes-Benz is here for it (courtesy of Farasis Energy).