Gizmorama - October 11, 2017
It looks as if the battery is keeping electric cars from taking off into the mainstream. Could a new type of battery be under development?
Learn about this and more interesting stories from the scientific community in today's issue.
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* Battery technology keeping electric car adoption in the slow lane *
When Tesla unveiled its mass-market electric vehicle, the Model 3, this summer, CEO Elon Musk promised the company would deliver 1,500 cars by the end of September. The latest reports suggest the carmaker has delivered 260.
While production bottlenecks are frustrating for Tesla investors -- and the some 500,000 deposit holders waiting for their cars -- that's not what's keeping electric cars from making true inroads in the mass market.
The major barrier is battery technology. And one questions stands out: Will the lithium-ion battery suffice?
"Today's technology is almost good enough," Gerbrand Ceder, a material scientist and engineer working on battery technology at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, told UPI. "Further cost reduction and 'incremental' improvements can take EV's to the 300-mile range. Together with fast charging this can take EV mainstream."
Not everyone agrees.
Scientists and engineers are working in a variety of capacities to improve the electric car battery on several fronts, including efforts to boost its power, range, safety and durability. These efforts fall into two categories: research into incremental changes and research into step changes.
"Today, all modern batteries are dominated by one type of chemistry -- lithium-ion," George Crabtree, director of the Joint Center for Energy Storage Research at Argonne National Laboratory, said.
Those working on incremental change are focused on improving the lithium-ion battery, while those with their hearts set on step changes are trying to invent a new type of battery.
Incremental changes are to thank for the Tesla Model 3's industry-leading range. Working with researchers at Panasonic, Tesla has steadily tweaked the chemistry and components of the lithium-ion battery to meet the demand of its vehicles. The tweaks have yielded significant cost savings and a 60 percent increase in range. The Model 3 boasts a range of 220 miles and its extended range battery can provide power for 310 miles.
The incremental change blueprint is one followed by the majority of the battery technology industry.
"Historically, this is true, the advances in performance and price have come from a long line of incremental improvements over the last 25 years since Li-ion was introduced in 1991," Crabtree said. "However the introduction of Li-ion in 1991 was itself not incremental but a step advance. Its energy density was twice that of the next best batteries."
Lithium-ion batteries provide power, a flow of electrons, by moving lithium ions from one electrode to another across an electrolyte. The negative electrode is called an anode, and the positive electrode is called a cathode.
Many scientists are experimenting with different anode materials to boost the lithium-ion battery's power and energy density while bringing down cost.
"Right now, most anodes are made of graphite," Crabtree said. "The lithium goes in-between the layers of the graphite. We can fit one lithium for every carbon atom in the anode. Silicon interpolates four lithium for every silicon atom."
Unfortunately, silicon expands dramatically during the charging and discharging process. Over time, this action will break down the battery. The solution is to mix graphite and silicon.
"The more silicon you put in, the more energy density you can take on," Crabtree said. "You get energy density up, you up the capacity, you up the range."
But at what cost? How much silicon can you put in before you sacrifice safety and durability? Scientists are trying to find out.
"Some scientists are considering replacing the the graphite anode with exclusively lithium," Crabtree said. "That's been a goal since the 1980s."
The problem is that the lithium becomes degraded over time. The layer becomes deformed, roughed up and begins to grow dendrites. These fingers of lithium grow out from the anode and damage the rest of the battery.
"The dendrite growth problem has been around for 40 years," Crabtree said.
The effort to improve the Li-ion battery's anode -- and the incumbent challenges -- offers a snapshot of the problematics of incremental improvements. Scientists don't completely understand battery chemistry, and their understanding is especially rough during experimental phases. With each new tweak and each new material, new challenges and drawbacks inevitably surface.
"Whenever several materials are brought together -- in a battery, for example -- there are lots of chemical reactions that can take place," Crabtree said. "Some of these are the desired energy storage reactions that will make the battery work, some are side reactions that are irrelevant for battery function but occur anyway because they are chemically favorable. When good ideas for batteries fail, these side reactions are usually the reason."
Scientists are split over whether the slow, slog of incremental change will be enough to take the lithium-ion battery and electric car mainstream. Even Musk has acknowledged that the potential of lithium-ion may soon be maxed out.
A range of 300 miles is a major improvement, but will it be enough? The extended-range version of the Model 3 costs $44,000, more than twice the price of some compact gas cars. Electric car owners must also work 30-minute charging periods into their routine. Filling up a gas tank typically takes no more than 5 minutes.
Despite some resignation that the lithium ion battery might not have what it takes, the majority of research funding is being funneled into projects focused on incremental change.
"I wouldn't be afraid to say more than 90 percent of funding and research is focused on gradual change," Crabtree said.
But even for many startups working on gradual improvements, funding is scarce.
While Tesla has invested billions into its efforts to improve the Li-ion battery, startups' efforts often have to get by on just a few million dollars per year. Many of the scientific tools needed to study the chemical reactions that could boost battery power are too expensive for small research outfits.
"Battery development is a long play," Ceder said. "That is why it is very hard for startups to do. Big companies need to step up here, potentially together with government incentives."
If funding for incremental change research is difficult, finding financing for step change research is nearly impossible.
"Pursuing step changes in performance is a high-risk enterprise -- several innovations have to work simultaneously, and no unexpected detrimental side reactions can occur," Crabtree said.
There is good news, though. Researchers have developed advanced computer modeling and molecule databases, like the Materials Genome Initiative, that allow scientists to streamline the experimentation process. Scientists can use the database and their advanced algorithms to identify promising compound combinations and new materials among millions of possibilities.
"Computer modeling is important because the requirements for novel battery materials are extreme and requires us essentially to look for a needle in a haystack," Ceder said.
Projects like the Materials Genome Initiative rely on public funding. Crabtree believes publicly funded research is essential to taking battery technology and electric cars mainstream. Research at innovation centers like Crabtree's JCESR "can create basic understanding that reduces the risk of failure of achieving a step advance," Crabtree said.
With risks minimized, and with objectives and challenges in clear focus, private companies, both big and small, can take over.
Even with public and private entities working together, technological progress is inherently slow, Ceder said. It always has been.
"It is important to keep in mind that commercialization is a very long path," he said. "Today's commercial battery materials were all developed at least 15 years ago, and in some cases much longer."
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