Tesla partner Panasonic says 30% energy density increase in lithium-ion batteries possible
By Carly Fortuna - Posted on April 10, 2017
The market for lithium-ion batteries (LIBs) is expected to exceed $33 billion by 2019 and $26 billion by 2023, according to global market research firm SIS International Research. The success of Tesla and its Nevada-based Gigafactory facility has generated a lot of excitement in the LIB industry. Panasonic’s automobile battery sales are forecast to grow to $4 billion a year by March 2019, largely due to their partnership with Tesla.
“We think the existing technology can still extend the energy density of LIBs by 20% to 30%,” Panasonic’s President Kazuhiro Tsuga said. “But there is a trade-off between energy density and safety. So, if you look for even more density, you have to think about additional safety technology as well. Solid-state batteries are one [possible] answer.” These safety concerns about LIBs are also pushing Panasonic to look at alternative battery power sources.
Solid state batteries use a solid electrolyte instead of the electrolytic solution that is essential in transporting the positive lithium ions between the cathode and anode in today’s batteries. Researchers have succeeded in developing an efficient electrolytic solid material that significantly improves lithium ion conductance, raising hopes that batteries with much higher power densities are edging closer to practical applications.
“For decades now we have been pushing the limits of our Li-ion batteries in terms of energy density,” Naoaki Yabuuchi, an associate professor at Tokyo Denki University, acknowledged. “Today’s best Li-ion cells can put out about 300 watts per kilogram; a package of Li-ion cells can give off from 150 watts to 250 watts per kilogram. These levels are already close to the theoretical maximum.”
Yabuuchi is an expert on various types of rechargeable batteries. In his view, LIBs will reach the limit of their desirability as early as the first half of 2020 if their development continues to rely on existing technologies. But he has hope that new research can open up more capacity. “Existing LIBs still have room to improve their energy density because you can raise the density by introducing a nickel-based cathode material, so you can expect the batteries will still be used in the next few years.”
It’s not just Tesla and its partners like Panasonic that are interested in LIB capacity. Range anxiety continues to plague possible Tesla and other EV brand buyers, as they fear an inability to travel far enough between vehicle charges and not having access to convenient charging facilities. “We want our electric cars to go 500 km [on a single charge],” said Shinji Nakanishi, a battery researcher at Toyota, via EVannex. “And for this, we want rechargeable batteries that can generate 800 to 1,000 watt-hours per liter.”
Battery research into alternatives to LIBs is quickly evolving. The Battery Symposium in Japan, once a showcase for fuel cells and LIB cathode materials, has seen a significant shift in recent years to industry presentations on solid-state, lithium-air, and non-Li-ion batteries.
Another possible LIB alternative, lithium-air batteries, has the ability to greatly improve energy density. At this point, however, researchers are stymied because lithium-air batteries suffer from poor cycle life. But researchers haven’t given up hope. They’ve been attempting to raise the density close to theoretically expected levels, even if it occurs only for a single charge cycle.
And an entirely different alternative to the LIB doesn’t even use lithium: a cathode material for the sodium-ion battery has a discharge capacity that beats LIBs and enables the power packs to be recharged upward of 500 times. That would circumvent one of the existing weakness that now limits this technology. Two nickel-based cathode materials, lithium nickel cobalt aluminum oxide and lithium nickel manganese cobalt oxide, are sometimes mentioned in these discussions, but neither seem to have a clear potential for practical use within the next decade, according to Yabuuchi.
Tesla is leading the global shift in the automotive industry from traditional gasoline powered vehicles to more fuel-efficient, environmentally responsible modes of transport. Musk has exclaimed that the 2170 cell is “the highest energy density cell in the world and also the cheapest.” Yet, as an industry disrupter, part of Tesla’s vision has been to constantly evaluate new battery technologies. Back in 2013, Ted Merendino, a Tesla product planner, noted that “Tesla has one of the largest cell characterization laboratories in the world. We have just about every cell you can imagine on test.”
That constant inquiry behind the scenes into cell characterization at Tesla may become prudent in previously unforeseen ways. Recently, for example, with the lithium market in its most severe shortage in modern memory, Musk insisted that the amount of lithium in a LIB is about 2% of its total volume and that “lithium in a salt form is virtually everywhere… there is definitely no supply issues with lithium.” Some in the industry disagree with lithium’s resource stability, however, so that alternative battery research may end up offering good karma.
In 2016, sales of LIBs for electric vehicles increased by some 66%, up from 12.3 GWh of capacity to 20.4 GWh. LIBs are the go-to source for EV power right now. Many other products use LIBs: chainsaws, mini-cameras, solar window chargers, wheelchairs, bicycles, portable self-charging desks.
But, with safety issues surrounding LIBs, the limitations of their charge capacity, and lithium market limitations, will Tesla invest in R&D toward alternative battery development so it sooner-than-later adds battery alternatives to its catalog?
Of course, advances from R&D take years to make their way to the marketplace, but should one or more of these promising technologies be translated for commercial means, then we may see innovative improvements in batteries, which could also enhance the performance and cost of our beloved Teslas.