Chinese battery giant CATL unveiled a new fast-charging battery last week — a battery that the company says can increase range by up to 400 kilometers (about 250 miles) in 10 minutes.
That’s faster than virtually all current electric vehicle charging, and CATL claims the new cells, which it plans to produce commercially by the end of 2023, will “open an era of super-fast electric vehicle charging.” That is, if the finished product can deliver on the company’s promises regarding battery capacity, lifespan, and cost.
Electric vehicles are representing a growing fraction of global new vehicle sales — 14% in 2022. But many drivers still worry about the limited range of current battery technology and are discouraged by the need to stop to charge for more than half an hour, even at fast charging stations. Innovation in battery materials, if combined with progress in charging infrastructure, could help mimic the convenience of gasoline-powered cars and encourage the adoption of electric vehicles.
CATL, whose name is an acronym for Contemporary Amperex Technology Co. Limited, is the world’s largest manufacturer of electric vehicle batteries. The company supplies cells to major car manufacturers such as Tesla, Mercedes and Volkswagen.
Last month’s announcement is the company’s latest high-profile technology news this year. Among other things, it plans to build high-energy-density condensed matter batteries for planes and mass-produce new batteries for electric vehicles made from sodium instead of lithium.
CATL’s new fast-charging batteries would be twice as fast as the competition, says Jiayan Shi, an analyst at BNEF, an energy research firm. Tesla’s fast charging increases range by about 320 kilometers, or 200 miles, in 15 minutes.
Some batteries on the market can already reach the speeds announced by CATL last week, says David Schroeder, technical director at Volta Energy Technologies, a venture capital firm focused on battery and energy storage technology. But these batteries are used in products like stationary energy storage. CATL would be the first to put these fast charging cells in electric vehicles.
With lithium-ion batteries, there tends to be a big difference between how much energy they can store and how quickly they can charge. In general, these batteries can be divided into two categories: “energy cells” and “power cells”. Power cells prioritize accumulating as much energy as possible, which is useful for increasing the range of an electric vehicle without increasing the volume too much. Power cells, on the other hand, tend to prioritize rapid charging and discharging, which is useful for uses such as stationary energy storage that stabilizes the electrical grid.
Currently, power cells can achieve fast charging speeds, but they may be too bulky to be used in a car and would likely not last hundreds of thousands of miles. Batteries that can be charged quickly while still being small, light and long-lasting would be a breakthrough.
The balance between high capacity and fast charging comes down to the way charged molecules, called ions, move around in batteries. When a battery is charged, an electrical current pushes lithium ions from one side of the cell to the other. The ions can then nestle into spaces in the part of the battery called the anode, where they wait. Eventually, they will come rushing back, releasing stored electricity when someone uses the battery to power a device.
To increase the total capacity of a battery, these anodes can be manufactured with thicker layers of material, meaning there will be plenty of room for the ions to fit into. However, in batteries with thicker anodes, some of the storage space will be at the bottom of the layers, so the ions will have to travel further to get there, slowing the charging process. To speed up charging, battery manufacturers can thin these layers so the ions don’t have to travel as far.
Innovations in materials could help overcome this disadvantage. In CATL’s announcement about its fast-charging battery, the company mentions several changes to the anode, including modifications to the graphite surface and a multi-layer design to help shorten the ion path and speed up charging.
But it’s not just the anode — every part of the battery appears to be contributing to faster charging speeds, says Kevin Shang, senior research analyst at Wood Mackenzie, an energy consultancy. The company’s statement also credits a new electrolyte (the liquid through which ions move in a battery) that improves conductivity, for example. With their new products, battery giants like CATL are not necessarily betting on a single innovation, but taking a series of research and development efforts together and combining them into a single product, says Shang.
However, there are still questions about this battery and what it will mean for vehicles, Shang says. By saying the batteries could be used in a vehicle with a range of 700 kilometers (430 miles), CATL’s announcement implies high energy density. But it’s unclear how big the vehicle and battery will need to be to provide that kind of range.
Plus, a higher charging rate generally means a shorter lifespan and a higher price, says Schroeder. In response to a written question from MIT Technology Review about the lifespan of new fast-charging batteries, CATL said: “Whether fast-charging or not, the warranty on our products remains the same.” (The current warranty lasts eight years or 500,000 miles, according to the website). The company also said it had “improved cost efficiency” but did not provide details on the battery’s price.
Ultimately, how quickly batteries can be charged will be limited not only by their design, but by the available charging infrastructure. Although China is a world leader in charger installations, many more electric vehicle chargers will be needed to meet growing demand. It is also possible that new chargers will be needed to achieve the charging speeds that CATL’s new batteries can support, presenting further challenges for infrastructure development.
Announcements from battery companies about progress are “always good news,” says Shang, “and we welcome them.” The question is whether companies can actually deliver on what was promised.
Sources/credit: MIT Technology Review
