New cold-hardy electrolyte could double EV range

With existing battery electrolytes, many electric vehicles struggle to maintain decent range in cold temperatures

Depositphotos

From New Atlas

A joint team of researchers from Nankai University in Tianjin and the Shanghai Institute of Space Power Sources (SISP) has developed a hydrofluorocarbon-based electrolyte that significantly enhances the performance of lithium batteries. As reported by the South China Morning Post, the new electrolyte more than doubles the energy density of existing batteries at room temperature, meaning batteries of the same size can last twice as long.

The researchers also claim that the new electrolyte remains stable in extreme cold, allowing batteries to function seamlessly in temperatures as low as -94 ºF (-70 ºC), well over 2.5 times the temperature of your refrigerator.

Chemical batteries, such as lithium batteries, utilize electrolytes – a chemical medium that allows ions to flow between the positive and negative electrodes, converting stored chemical energy into electrical current. In lithium batteries, the electrolytes are usually nitrogen- and oxygen-based compounds, mainly because of their effectiveness at dissolving lithium salts.


However, these electrolytes are sensitive to operating temperatures. Cold temperatures increase viscosity and slow down ion mobility, reducing charge transfer efficiency. When this happens, the battery delivers less power, takes longer to charge, and loses usable capacity, providing less runtime than its stored energy would suggest. This is why lithium batteries appear to die quickly in extreme cold. In certain conditions, such as charging the battery when the temperature is below 32 °F (0 ºC), permanent damage may occur.

In the study published in Nature, the researchers outlined how their solution, synthesized hydrofluorocarbon-based (hydrogen, fluorine, and carbon) electrolytes, eliminates this problem in lithium batteries. The cold-resistant electrolyte offers improved stability and lower viscosity at low temperatures, enabling batteries to continue operating efficiently below -94 °F.

Another outstanding feature of the electrolyte is its energy density – the amount of charge it can store per weight. In the study, the team created lithium metal pouch cells that achieved an energy density of 317 watt-hours per pound (Wh/lb) at room temperature. The cells still maintained a density of 181 Wh/lb at -50 °F (-46 ºC).

In comparison, conventional lithium batteries, such as those found in Tesla EVs, have an energy density of 73-136 Wh/lb at room temperature. This figure more than halves when temperatures fall to just -4 °F (-20 ºC).Technically speaking, the researcher’s electrolyte could triple the range of some EVs with the same battery size!

“For the same mass of lithium battery, the room temperature energy storage capacity is increased by two to three times,” said study author Li Yong, a researcher at SISP.

Beyond the automotive industry, this development could have far-reaching implications across many sectors and everyday life. We are talking drones, robots, smartphones, and consumer electronics that last twice as long while still being able to operate efficiently in extreme cold.

Research robots operating in Antarctica could function reliably, while subsea exploration vehicles could significantly extend their operational range. Similarly, satellites and spacecraft, which endure extreme temperature swings in orbit, could benefit from more stable and predictable power systems. The list goes on and on.

Before we get carried away, it's important to note that the electrolytes are not exactly “all weather” ... yet. The team noted that the electrolyte’s high-temperature stability still needs improvement. Should they succeed in raising the boiling point of the electrolyte, we could have a true all-climate solution.

 

Source: Nature 

 

This is obviously still at the laboratory stage, and as such, may never enter commercial production. However, you may depend upon it: engineers at Chinese and other countries' battery manufacturers will have read the article in Nature, and will be keenly examining the results to see if there is any way they can increase the range and reduce the cost of their own batteries.  There is a ferment in battery technology and manufacture, and the likely outcome is more of the same: plunging costs, higher energy density, and greater range.  Sodium-ion batteries, for example, which also allow low-temperature use, are just one of the ways battery makers have slashed costs.  This new electrolyte keeps lithium-ion in the game. 

CATL's second-gen sodium-ion battery

Photo by: InsideEVs

From Inside EVs

China is reaching new heights in diversifying the battery chemistries used in electric vehicles. The country is already leading in subcategories of lithium-based chemistries, like nickel-manganese-cobalt (NMC), nickel-aluminum-cobalt (NCA) and lithium-iron-phosphate (LFP). Earlier this year, state-run utility company China Southern Power Grid even deployed sodium-ion batteries for stationary energy storage. Now CATL, the world's largest battery maker, claims to have unlocked new levels of extreme weather performance with sodium-ion batteries.

The role of sodium ions is similar to lithium ions, where charge-carrying ions travel between the positive and negative electrodes during the charge and discharge cycles. Studies suggest that sodium-ion batteries could eliminate the pesky traits of lithium-ions: There’s less risk of thermal runaway, they can operate at varied temperatures and crucially, the cost of sodium hydroxide, a key raw material, is far lower than lithium-hydroxide. (Although battery companies have reached better economies of scale with lithium-ions.)

Sodium-ion batteries have already entered production in China. Cars that use them include the Yiwei EV produced by Volkswagen-backed JAC and the JMEV EV3. Speaking at the World Young Scientists Summit, CATL chief scientist Wu Kai said that its second-generation sodium-ion cells can discharge normally even at -40 degrees Celsius, as per several local Chinese media reports. That means EVs with such batteries won't lose range under frigid temperatures, which could help address some of the lingering concerns regarding the extreme weather performance of batteries.

They will launch in 2025 in China, with mass production expected to begin in 2027.

Tesla's 4680 NCM cells present in some newer Model Ys have an estimated energy density of up to 296 watt-hours per kilogram, as per some early teardowns. Sodium-ion batteries are less energy dense. While CATL has not disclosed the energy density of the new cells, it reportedly aims to reach a figure of 200 Wh/kg—a tough goal given that even LFP batteries have only recently hit that mark. That would only be appropriate for low-range EVs or entry-level trims. Some reports also claim that sodium-ion batteries are expected to replace 20-30% of LFP batteries in select applications.

A study published in the U.S. government’s National Library of Medicine calls sodium-ion batteries a “rising star.” Battery giants like CATL, BYD, and Sweden’s Northvolt are already investing in and developing these next-generation cells. So either way, one thing is clear: the future of battery chemistry isn’t headed in a single direction but will likely embrace a mix of chemistries tailored to specific use cases.

In principle, sodium-ion batteries should be cheaper than lithium-ion, because sodium is far more common and far cheaper than lithium (salt is sodium chloride, and the sea is full of it).  But production is still limited, so they are not cheaper yet.  As volumes expand, though, they will fall in cost just as fast as lithium-ion batteries have fallen, cutting battery cell costs to below $35/kWh, and battery pack costs to ~$65/kWh.  At that price, the average EV battery pack will cost between $2600 and $4000, making EVs cheaper to buy as well as to run than petrol cars.   For reference, in 2010, lithium-ion batteries cost $1392/kWh.  Expect EVs to rapidly move to 100% of all sales, as costs continue to plunge--except of course in the US, where tariffs will stop this happening.  They already make up more than 50% of sales in China, the world's largest car market.  

Because of lower energy density, initially battery-packs will combine sodium-ion and lithium-ion cells.  But cheaper cars, with shorter ranges, will be the first to get 100% sodium-ion batteries.  

Heart Aerospace's updated electric plane

Heart Aerospace's ES-30 electric plane.

I first talked about this new electric plane here. The design has been changed to increase passenger capacity from 19 to 30, and to increase range by adding a hybrid option.  These electric planes have engines which cost a 20th of turboprop engines, and the planes are 50% cheaper to operate.

From Heart Aerospace's website:

Swedish electric airplane maker Heart Aerospace today unveiled significant design updates to its first electric aircraft and confirmed Air Canada, one of North America’s largest airlines and Saab, the Swedish aerospace and defense company, as new minority shareholders.

The new airplane design, called the ES-30, is a regional electric airplane with a capacity of 30 passengers and it replaces the company’s earlier 19-seat design, the ES-19. It is driven by electric motors powered by batteries, which allows the airplane to operate with zero emissions and low noise.

Air Canada and Saab have each invested USD 5 million in Heart Aerospace. In addition to its investment, Air Canada has also placed a purchase order for 30 ES-30 aircraft.

“We are thrilled to have two such strong partners as Saab and Air Canada join our mission to electrify regional air travel. Growing up in Sweden, Saab is synonymous with aerospace, and our partnership will not only support our programme, but help us to become a part of the proud Swedish aerospace heritage,” said Anders Forslund, founder and CEO of Heart Aerospace. “Air Canada is a strategically important partner with one of the world’s largest networks operated by regional turboprops, and as a progressive, future leaning company.”

“Air Canada is very pleased to partner with Heart Aerospace on the development of this revolutionary aircraft. We have been working hard with much success to reduce our footprint, but we know that meeting our net-zero emissions goals will require new technology such as the ES-30. We have every confidence that the team at Heart Aerospace has the expertise to deliver on the ES-30’s promise of a cleaner and greener aviation future,” said Michael Rousseau, President and Chief Executive of Air Canada.

The ES-30 has a comfortable three-abreast flat-floor cabin seating and it features a galley and a lavatory. Cabin stowage and overhead bins will add to the large external baggage and cargo compartment and provide airlines with network flexibility.

The airplane will also include a reserve-hybrid configuration, consisting of two turbo generators powered by sustainable aviation fuel. The reserve-hybrid system is installed to secure reserve energy requirements without cannibalizing battery range, and it can also be used during cruise on longer flights to complement the electrical power provided by the batteries.

This gives the airplane a fully electric range of 200 kilometers, an extended range of 400 kilometers with 30 passengers, and flexibility to fly up to 800 kilometers with 25 passengers, all-inclusive of typical airline reserves.

“The ES-30 is an electric airplane that the industry can actually use. We have designed a cost efficient airplane that allows airlines to deliver good service on a wide range of routes,” said Anders Forslund, founder and CEO of Heart Aerospace. “With the ES-30 we can start cutting emissions from air travel well before the end of this decade and the response from the market has been fantastic.”

“This underlines our commitment to innovative technology and solutions for sustainable aviation. Heart is a pioneer within commercial electric aviation and we look forward to contributing to the future of aviation with our experience of developing solutions at the forefront of technology,” says Micael Johansson, Saab’s President and CEO.

Previous orders for Heart Aerospace’s ES-19 electric airplane, placed by United Airlines and Mesa Air Group for a total of 200 electric aircraft with an option for an additional 100 planes, are reconfirmed for the updated ES-30 design.

“From the beginning Heart and United have been on the same page – with an acute focus on safety, reliability, and sustainability. Heart’s exciting new design – which includes expanded passenger capacity from 19 to 30 seats, and a state-of-the-art reserve-hybrid engine – is the type of revolutionary thinking that will bring true innovation to aviation,” said Scott Kirby, CEO of United Airlines.

In addition to those commitments, many of the ES-19 letters of intent (LOI) holders have already updated their respective letters to reflect the ES-30. These include the Nordic airlines Braathens Regional Airlines (BRA), Icelandair and SAS as well as New Zealand’s Sounds Air. Rockton, a Swedish-based lessor who has made it their mission to focus on sustainable solutions for the Industry, has just signed an LOI with [HA] for up to 40 airplanes.

In total, Heart Aerospace has LOIs for 96 ES-30s. [This is presumably in addition to the orders of 100 each from United and Mesa airlines.]

The ES-30 is a cost efficient airplane that, on top of significant fuel savings, is cheaper to operate than a larger turboprop due to its electric propulsion. The airplane has also been designed to accommodate battery technology evolution, which will increase its fully electric range and make it even more cost efficient over time.

The ES-30 is expected to enter into service in 2028.  [This has slipped from the initial 2026 deadline]

Adding a hybrid option makes the ES-30 more flexible than the ES-19.    The problem now is sustainable fuel.   But the costs of green hydrogen/green methane (and therefore also green jetfuel) are falling fast as the costs of renewable electricity declines.  The 800 km extended range means that the plane can be used on most regional air routes.  And by 2028, the energy density of batteries will have increased by another 3.5 times, if past trends continue.   Even if conventional fossil-derived jetfuel is used for the range-extending turbines in the hybrid version, it will still reduce emissions from air travel.

9-Fold increase in battery energy density

"Source: Nitin Muralidharan, Ethan C. Self, Marm Dixit, Zhijia Du, Rachid Essehli, Ruhul Amin, Jagjit Nanda, Ilias Belharouak, Advanced Energy Materials, Next-Generation Cobalt-Free Cathodes – A Prospective Solution to the Battery Industry's Cobalt Problem, January 2022."

From Inside EVs

During the past decade, lithium-ion batteries improved significantly in terms of volumetric energy density, which describes the amount of energy that can be contained within a given volume.

The higher the volumetric energy density is, the smaller the battery pack can be (assuming the same energy content).

It's not the only metric, as there is also the gravimetric energy density, which tells how much energy can be stored per weight unit. The higher it is, the lighter the battery pack can be.

In the new weekly presentation, the Department of Energy’s (DOE) Vehicle Technologies Office highlights how the volumetric energy density of lithium-ion batteries (industry average for battery packs) changed between 2008 and 2020.

The progress is tremendous, as in 2008 the number was only 55 Wh/Liter, while in 2020 it was 450 Wh/l, according to the study. That's an 8-fold increase in 12 years.


Progress (on the pack level):2008: 55 Wh/l
2010: 90 Wh/l
2013: 140 Wh/l
2017: 250 Wh/l
2020: 450 Wh/l


We strongly believe that those industry average numbers have improved since then and in 2022 are even higher.

A lot depends on lithium-ion battery chemistry, as there is a very wide difference between particular solutions - up to an order of magnitude.

We often focus on the gravimetric energy density to make electric vehicles lighter and thus improve efficiency and range. However, the volumetric energy density is also very important for EVs, to make the battery smaller and fit inside the vehicle, increasing space for other elements and the passenger/cargo compartment.

Rechargeable aluminium for seasonal storage

 A fascinating idea. 

From New Atlas

Aluminum has an energy density more than 50 times higher than lithium ion, if you treat it as an energy storage medium in a redox cycle battery. Swiss scientists are developing the technology as a renewable energy stash for the European winter.

The problem is simple enough: as countries worldwide plan their moves toward zero-emissions energy, they need to deal with the intermittent nature of cheap renewable energy. On a daily basis, solar harvests most of its energy in the middle of the day, and this necessitates some kind of short-term storage solution that can park that energy in some form of battery, then release it again in the evening when everyone gets home and starts running TVs and dishwashers. These kinds of big battery projects are already installed in many areas and proving their worth.

But intermittency is a much bigger issue on a seasonal level. The further you move from the equator, the less Sun you get in the winter months. Parts of Scandinavia famously get no Sun at all for months on end – resulting in some pretty epic springtime parties, I'm told – but a much broader area is going to find itself very short on solar, every year, right when everyone's starting to crank up their heaters. The zero-carbon world needs a way to store absolutely massive amounts of excess renewable energy generated in the warmer months, then release it through the long winters. And it'll need to be affordable, or else it's not going to happen.

Researchers from Switzerland's SPF Institute for Solar Technology have been studying aluminum redox cycles for many years now, and with funding from the EU's Horizon Europe program and the Swiss government, they've just kicked off a research project called Reveal, drawing in nine different partners from seven European countries, to develop what looks like a very promising idea.

As a 2020 report from the SPF team states, a single, one cubic meter (35.3 cu ft) block of aluminum can chemically store a remarkable amount of energy – some 23.5 megawatt-hours, more than 50 times what a good lithium-ion setup can do, or roughly enough to power the average US home for 2.2 years, on 2020 figures. That's by volume – going by weight, aluminum holds a specific energy of 8.7 kWh per kilogram, or about 33 times more than the batteries Tesla uses in its Model 3.

Big fat blocks like that aren't exactly practical to work with, though, so the Reveal team proposes using 1-mm (0.04 in)-diameter balls of aluminum instead. Naturally, you lose some volumetric density here, but you're still coming out over 15 MWh per cubic meter.

Aluminum holds a phenomenal amount of energy compared to batteries or hydrogen

SPF Institute for Solar Technology

Getting that energy in and out is, of course, a lot more involved. During the "charging process," excess renewable energy would be used to convert aluminum oxide, or aluminum hydroxide, into pure, elemental aluminum. This is an industrial electrolysis process, requiring temperatures around 800 °C (1,472 °F), as well as novel inert electrodes, if you want to avoid the carbon dioxide emissions that accompany today's conventional aluminum smelting processes.

The team estimates it'll be possible to "charge" an aluminum redox system like this at an efficiency around 65%. All the raw materials here are relatively cheap and abundant, some of them indeed being scrap, with the added benefits of being very simple to store and transport. Yes, aluminum oxidizes on contact with ambient air, but it's only a surface layer, less than half a nanometer thick, representing a chemical energy loss of "far less than 1%" when those tiny 1-mm balls are stored in air.

To discharge the aluminum, you simply convert it back again. This can be done at low temperatures, using aluminum-water reactions at less than 100 °C (212 °F), generating aluminum hydroxide, along with pure hydrogen, which can be run straight into a PEM fuel cell stack for conversion to electricity. The process and the fuel cell also generate heat, which can be recovered at temperatures relevant for space heating or domestic hot water.

Inputs and idealized outputs of the low-temperature aluminum-to-hydrogen energy release process, assuming a fuel cell efficiency of 50%

SPF Institute for Solar Technology

There's also a higher-temperature process, running at over 200 °C (392 °F), which reacts the aluminum with steam to generate aluminum oxide, hydrogen and much higher levels of heat, more relevant for industrial applications.

In the Reveal model, the charging process would be done at central smelting depots, and the "charged-up" aluminum would be trucked out in bulk to be "discharged" on-site at apartment buildings, industrial facilities, and even individual homes, since the equipment needed is relatively simple and low-maintenance – well, apart from the fact that the aluminum-to-hydrogen conversion system doesn't exactly exist yet at this point.

Once it's out of juice, the aluminum oxides and hydroxides would be sent back to the depot for "recharging." Ideally, the Reveal team says, this aluminum will be cycled back and forth in this process indefinitely, so there won't be any ongoing raw material costs for a given system.

Eviation electric plane gets first large order

 I've talked before about Eviation's electric plane.  

Now Massachusetts-based Cape Air has signed an order for 75 of these all-electric planes.  Electric planes for short-haul flights are going mainstream, partly because they're so much cheaper to run than jets or jet-prop planes.  Battery energy density is still not high enough for long-distance flights, but short-distance trips are now feasible.

From Geek Wire

A Seattle-area venture called Eviation has struck a deal with Massachusetts-based Cape Air for the purchase of 75 Eviation Alice all-electric planes.

The letter of intent follows up on a claim that was made back in 2019 by Eviation’s then-CEO, Omer Bar-Yohay, who said Cape Air would be his company’s first customer. At the time, Bar-Yohay said the list price for the Alice commuter aircraft would be $4 million per plane — but Eviation said it’s not releasing financial details about the Cape Air deal.

Bar-Yohay left Eviation in February, citing “a longstanding disagreement” with the company’s main shareholder, Singapore-based Clermont Group. Longtime aerospace executive Gregory Davis took over as interim CEO for the privately held company, which is headquartered in Arlington, Wash.

Eviation has begun ground tests of an Alice prototype, and those tests haven’t always gone perfectly — which is to be expected with a totally new type of aircraft. In February, Eviation said Alice’s first flight test would take place “in the upcoming weeks,” but the company now says it plans to reach that milestone this summer.

Alice will be powered by two 850-hp electric motors made by MagniX, a Clermont Group company that’s based in Everett, Wash., close by Eviation’s HQ. It’s designed to carry up to nine passengers and two crew members on zero-emission flights ranging as far as 440 nautical miles (500 statute miles) on a single charge.

If all goes according to plan, Eviation aims to have the production version of the Alice aircraft flying in 2024, with deliveries to follow certification activities.

As a commuter airline, Cape Air is in the sweet spot when it comes to the market for Alice. Although the company is based in Massachusetts, it serves nearly 40 cities in the U.S. (including cities in eastern Montana) and in the Caribbean.

“Truly sustainable aviation not only reduces the impact of air travel on the environment but also makes business sense,” Jessica Pruss, vice president of sales at Eviation, said in a news release. “We are proud to support Cape Air, a recognized leader in regional air travel, to chart a new path in delivering innovative solutions that benefit airline operators, passengers, communities and society.”

Eviation also envisions Alice being used for cargo shipments and for executive business travel. Last year, DHL Express said it was ordering a dozen Alice eCargo airplanes.

Several other ventures are pursuing approaches to electric aviation. MagniX, for example, plans to retrofit seaplanes operated by Vancouver, B.C.-based Harbour Air and is working with other partners as well. Last year, MagniX won a $74.3 million contract from NASA to demonstrate electric propulsion technologies for aircraft.

Meanwhile, Amazon and Alaska Air are investing in ZeroAvia, a venture that’s developing a hydrogen-electric hybrid airplane and is setting up a research and development facility in Everett. Amazon’s Climate Pledge Fund has also provided funding for another electric aviation startup called Beta Technologies.

Battery energy density has tripled since 2010

 From CleanTechnica

BloombergNEF‘s Colin McKerracher took to the stage at the BloombergNEF Summit in San Francisco last week where he made a case for electric vehicles reaching the “end of the beginning.” The case for electric vehicles moving into the mainstream or out of the early adopter stage of growth has been fueled by the increase in energy density in lithium-ion batteries and the corresponding drop in cost that comes along with it.

Battery energy density is the amount of energy that can be stored in the same amount of weight. Think about it as the amount of range that can be extracted from the same 500 kilogram (1102 pound) pack. As energy density increases, more energy can be extracted from a battery pack of the same weight. “Battery energy densities keep getting better,” Colin McKerracher, Head of Advanced Transport at BloombergNEF, said. “They’ve almost tripled at the cell level since 2010.”

These improvements are staggering and have paved the way for an electrified future. As energy densities improve, longer range electric vehicles make their way to the market without the need for physically larger, heavier packs. This trend can be seen in the Tesla Model S, which came to market with a ~250 mile (402 km) range per charge. The most recent Model S with its Long Range Plus battery pack can achieve 390 miles (628 km) of range per charge. It can also be seen with the longer range the Nissan LEAF has gained continuously since 2011, going from 73 miles (117 km) of range back then to 215 miles (346 km) in 2020 (nearly a tripling, incidentally).

Improving energy density enables other meaningful wins across the board with electric vehicles. As density improves, the same 100 kWh pack gets lighter. Lighter battery packs translate to lower freight and handling expenses throughout the supply chain, further lowering the cost of the battery. McKerracher commented about battery pricing as well, noting that the price of lithium-ion batteries has continued to fall in recent years. The trend is expected to continue in 2020, with BloombergNEF estimating a price drop from $156/kWh in 2019 to $135/kWh in 2020.