ELECTROMOBILITY The current state of EV battery development
Electric vehicle adoption is expected to accelerate in the next decade. Lowering prices, public awareness and improved manufacturing techniques are at the center. The major holdback has been all-electric range. How will manufacturers conquer the restrictions of traditional lithium-ion batteries? These are some of the developments happening in EV batteries currently.
A gas-powered car battery is a six-cell component that weighs in at 41 pounds, on average. The 85-kWh lithium-ion battery pack in a Tesla Model S is approximately 1,200 pounds made up of 7,104 cells. It has an impressive range of 265 miles, but when the battery is depleted, it takes 3.5 hours to recharge at 220V. That’s much, much longer than a fuel stop for an internal combustion engine-powered car.
To make EVs more attractive to the end user, a fast-charging, high-capacity battery is one of the major hurdles to clear. Where are manufacturers in the development process now?
Lithium Iron Phosphate
The most recognizable name in EVs and arguably the industry leader, Tesla, is constantly working on new battery tech. That includes lithium iron phosphate cathodes that are free from cobalt. That’s particularly important because cobalt is a mined resource that’s costly and often linked to unethical mining practices.
Iron and phosphorous are readily available resources, and procurement of these elements could drastically reduce the environmental impact of mining for cobalt to use in batteries. Lithium iron phosphate batteries have longer lifecycles and higher discharge and recharge rates. The trade-off is that iron phosphate has a lower energy density so battery packs could increase in size. Tesla’s solution could be to change from cylindrical cells to prism-shaped cells that tightly pack together.
One of the Nobel Prize-winning lithium-ion battery inventors has submitted a patent application for a glass battery. The design adds sodium or lithium to glass to form an electrode in the battery. Making it appropriate for mobility applications are the facts that it’s more stable than other sources, can handle temperature extremes better, and is relatively low cost to produce.
Glass battery technology is reportedly capable of storing three times the energy of a traditional lithium-ion battery of a similar size and can withstand many more charge and discharge cycles than typical EV batteries. The potential includes reducing battery sizes and weights with the same range and performance, or maintaining the size and weight in a vehicle and extending the range by up to three times. The 1,000-mile EV barrier could be broken eventually.
Fast-Charging Battery Cells
A startup in Cambridge, England called Echion technologies has reportedly developed an anode for high-capacity lithium batteries to reduce the time it takes to recharge. The anode, which operates as a negative pole during use and a positive pole during charge, has been called a mixed niobium oxide anode by Echion. Niobium is used in superconducting alloys and magnets such as those in MRI scanners and is incredibly conductive in an oxide.
The mixed niobium oxide anode can be used in exchange for any other anode style to improve recharging. It’s compatible with conventional cathodes and electrolyte materials so it can be widely implemented. The bold claim about mixed niobium oxide anodes is that it can allow high-capacity lithium batteries to recharge in as little as six minutes.
Lithium Sulphur Batteries
Like lithium iron phosphate, lithium-sulphur could become a replacement for batteries that contain heavy metals. Researchers at Monash University have developed a lithium-sulphur battery design, tested on a cell phone, that held charge for five days. As a common element, sulphur would greatly reduce the mining costs that impede EV battery development and adoption.
Monash researchers theorize that lithium-sulphur batteries can store more energy than lithium-ion by as much as six times. Until now, they have been unstable as the energy causes the battery to break apart. A commercial product is expected in two to four years.