Technologies propres

Redwood Materials a de bonnes nouvelles concernant les voitures électriques – CleanTechnica

Horodatage : 26 avril 2024 12:17 PM
Nœud source : 2737077

Republié par Platon

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A few days ago, a writer I hold in the highest regard penned a story for CleanTechnica that exposed the seemingly endless litany of things that are wrong with electric cars from the perspective of someone who is a tool of the fossil fuel industry. Much of that screed focused on how the batteries for electric cars require large amounts of raw materials that have to be wrested from the Earth and refined — things like lithium, cobalt, and nickel. The author seemed to think those materials are only used to build electric cars, as if no other consumer products use them.

The counterpoint to the lies peddled by that author — which were broadcast by Faux News, naturally — is happening in Nevada at this very moment. That’s where Redwood Materials, the battery recycling company founded by former Tesla chief technology officer JB Straubel, flipped the switch this past week to begin recycling of lithium-ion batteries at scale.

Redwood Makes Battery Materials In The US

Tom Randall of Bloomberg visited the site recently and reported that recyclers like Redwood Materials will eventually need to match the pace of car factories. For example, the Tesla factory in Fremont, California produced 560,000 EVs last year. When the batteries in those cars are recycled, they will create almost 10 times as much EV battery material as the entire US market processed last year. If US recyclers can handle all of that, they would begin to rival traditional mining operations and battery materials suppliers, most of whom are in China.

“Once we’ve changed over the entire vehicle fleet to electric, and all those minerals are in consumption, we’ll only have to replace a couple percent each year that’s lost in the process,” said Colin Campbell, Redwood’s chief technology officer and the former head of powertrain engineering at Tesla. “It will become obvious to everyone that it doesn’t make sense to dig it out of the ground anymore.”

Straubel himself told Randall that Redwood is attempting to break China’s stranglehold on battery materials by creating a domestic loop using recycled critical metals. “The responsibility weighs on me,” he said. “I remember feeling it in the early days at Tesla, when the other manufacturers hadn’t done crap yet, and we had a very palpable sense of holding the flag and running out into the field and saying ‘EVs are the future!’ We felt that if we failed, well, nobody’s going to follow. This is a little déjà vu. »

How To Recycle A Battery

There are three basic approaches to recycling batteries, each with its own drawbacks, Randall says. You can burn them, which is wasteful and can result in toxic emissions; dissolve them in strong chemicals, which is expensive and uses the most energy; or separate them mechanically, which can be labor intensive and dangerous. Until the last few years, most US recyclers simply ground up batteries and sent them overseas for someone else to deal with.

Redwood borrows what it sees as the most useful bits from each category. The company’s process starts in an indoor staging area where everything from discarded earbuds and laptop batteries to EV modules from recalled Chevy Bolts (now we know where all those defective Bolt batteries ended up) are dumped onto a conveyor belt. The jumbled mess is carried roughly 30 feet up to a hole in the wall where it exits the building into a giant churning metal tunnel, dubbed “RC1,” suspended high above the ground.

RC1 is essentially an enormous slow cooker that bakes the junk at several hundred degrees for about an hour, and is perhaps Redwood’s biggest innovation thus far. Traditional recycling through burning uses heat well over 1000º C (1,800º F) to separate out precious metals, but Redwood’s goal at this stage is to preserve and prepare the materials for the next steps in the most efficient way.

Most importantly, RC1 doesn’t use any oxygen. There’s no combustion and therefore no emissions. It simply reduces the glues, plastics, and unwanted fluids into charcoal. The high grade black carbon left over can be sold for use in black paints and industrial lubrication.

The RC1 also uses surprisingly little electricity, which is key to lowering Redwood’s climate impact. Once the kiln heats up, the energy released from the batteries is self sustaining. Think of it as a controlled, slow motion version of a battery fire, running nonstop day and night, week after week. It safely releases the charge in any batteries that could pose a danger to workers, while breaking down the stuff that binds key minerals together. (In some respects, the process sound vaguely similar to how biochar is made.)

After leaving RC1, the charbroiled batteries pass through machines that sift the material through screens. Powerful magnets are used to isolate certain materials. The remaining mineral-rich dust, known as black mass, is mixed into a slurry of solvents and fed into another building that resembles a large beer brewery, with towering stainless steel tanks that use chemicals, pressure, filters, and evaporation to separate products into their core elements.

Redwood Is Inventing As It Goes

Recycling batteries is still new technology and Redwood Materials is inventing the process as it goes along. An executive team plucked from Tesla’s top engineering ranks has been tweaking the battery-recycling process for speed and environmental efficiency even as it expands at industrial scale. What Redwood is doing drew the interest of researchers at Stanford who were given access to data by Redwood. Over the past two years, the Stanford team has conduct an environmental assessment of the Redwood battery recycling process.

But by the time the researchers finished analyzing a part of the Redwood process, they discovered the process had changed, said Will Tarpeh, an assistant professor of chemical engineering and one of the paper’s senior authors. “Month to month, they were always tweaking,” Tarpeh told Randall. “That made it challenging but was fantastic to see. They are navigating very well through a world where everything is shifting very quickly.”

The Stanford report, which is still under peer review, found that the Redwood recycling and refining operations cut carbon dioxide emissions by 70% compared with traditional recycling methods and 40% compared with other recycling processes. The savings were even greater when Redwood was dealing with manufacturing scrap, which currently makes up roughly half of the materials available for recycling.

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How To Make A Battery

Les Bloomberg article contains a lot of basic information on how batteries are manufactured that may not be common knowledge, even to sophisticated CleanTechnica readers. The holy grail for any battery recycler is to produce the expensive components that go into battery cathodes and anodes, Randall writes. Both products today are manufactured almost entirely in Asia.

Anodes are made from delicate copper foil that is typically coated with graphite. The foil is a tenth of the thickness of a human hair and comes in wide rolls that look like industrial-size wrapping paper. Each sheet, unraveled, would stretch for up to 15 kilometers (9 miles), and the slightest tear or puncture could lead to a defective battery cell. That helps put the complexity of making batteries into perspective. Workers at the Redwood anode foil shop wear full body coveralls with hair and beard nets and must pass through a chamber where they’re blasted with air jets before entering. A single errant hair or speck of dirt could ruin an entire roll of copper foil.

Copper foil production has never existed in the US before. For the last year, Redwood has been making sample rolls for potential customers to test. In the coming weeks, its foils will officially enter the supply chain to be used in American EVs, Straubel said, “It’s literally the first time anyone has made that material in the US — ever — for a battery.

Redwood currently has a single foil-making machine that can supply enough copper for more than 13,000 long range electric cars each year. A perfectly smooth titanium drum, roughly the size of a small car, spins half-submerged in a bright blue bath of liquid copper sulfate. As it gets zapped with tens of thousands of amps of electricity, a silky sheet of copper forms from the bath and is subsequently wrapped onto a long roll.

That tool will soon be joined by nine additional machines, with more to come soon at a factory under construction in South Carolina. By 2028, the two locations will have 100 machines in operation, producing enough foil each year to wrap around the planet six times, according to Straubel.

The cathode largely determines a battery’s performance, cost, and environmental footprint. Getting the recipe right for the final black cathode powder takes years of work in partnership with each manufacturer that will buy it. Samples must undergo many rounds of testing and qualification before being used in a car. At Redwood, workers at the cathode plant must don fully sealed suits, including helmets with breathing tubes and two sets of gloves to ensure a perfect barrier at the sleeves.

So much rides on cathode performance that once a product is approved for use by a major battery manufacturer, the commercial relationship tends to be permanent. “It’s almost the definition of high risk, high reward,” said Andy Leach, an analyst at BloombergNEF. The cathode line that Redwood commissioned in March will produce just 50 megawatts worth of cathode a year. Its primary purpose is to perform additional testing with customers before Redwood turns on the giant 20 gigawatt-hour versions late next year.

The Path Forward For Redwood Is Challenging

“China has had 10 years of seriously prioritizing EVs, so they are just ahead of the game,” said Lachlan Carey, US program manager at RMI. “There is a heck of a long way to go to catch up and a lot that could get in the way.” But having Straubel at the helm of Redwood is a selling point for investors who want to take a leap of faith today. He was the mastermind behind Tesla’s battery strategy, and his connections from Silicon Valley to Wall Street helped the company raise $2 billion in private funding and secure a $2 billion loan commitment from the Department of Energy that it can tap once certain milestones are met.

One recycler in the US won’t be enough to build a US manufacturing base for EVs, though. Straubel acknowledged that reality as well as the daunting math ahead. “The simple truth of it is that it’s a damn hard thing to do. It’s just shocking to me, given how much battery capacity is either online now or being built, and yet 100 percent of its supply chain is imported.”

Battery recycling is one of the areas that will make electric vehicles sustainable. Redwood Materials is reclaiming 95% of the materials needed to make EV batteries, and the process can be repeated over and over again. Try that with the used motor oil that comes out of the crankcase of the millions of conventional cars and trucks on the road. Recycling really is the last piece of the puzzle that will make personal transportation sustainable instead of a burden on the environment.

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