This week, Tesla’s Elon Musk unveiled his new lithium-ion battery pack that can deliver an unprecedented 315-mile range for his electric vehicles (EVs). But SolidEnergy Systems, a new startup spun out of an MIT lab, says it is in the process of commercializing a lithium metal battery that can double the range of all existing EVs.
A major roadblock to mass-market success of electric vehicles has been “range anxiety” — the concern that you’d run out of juice in the middle of your trip with no quick way to recharge. Vehicle price has been the other big roadblock. Both problems stemmed from the fact that batteries have historically been bulky, heavy, pricey, and slow to charge.
Yet the stunning learning-curve improvements in battery cost and performance of the last decade meant that we were fast approaching a tipping point:
Bloomberg New Energy Finance (BNEF) has concluded that a key range/price tipping point is a 200+ mile range EV at a cost of under $40,000, as I discussed in February. That’s why it’s such a big deal that both GM and Tesla were building 200+ mile range EVs for a list price well below $40,000. This game-changing range-price combo was a key reason that Tesla’s Model 3 has broken all records for vehicle presales.
But, of course, gasoline-powered cars typically get a 300- to 400-mile range. That’s why it was so significant that Musk announced this week that Tesla was able to tweak the size and architecture of the battery pack for its high-end Model S sedan and Model X sport-utility to give them over a 300-mile range.
Musk has said he expects to improve battery performance some 5 percent per year. In this case the steady improvements in energy density allowed him to replace 90 kWh batteries with 100 kWh batteries.
At the same time, the superfast charging stations that companies like Tesla are now building nationwide can charge a battery up to 80 percent of its capacity in 20 minutes. And a new MIT study finds that current EVs can already cover 87 percent of daily car travel — and by 2020, they should be able to cover 98 percent of daily car travel, as explained last week in a Technology Review article, “Why Range Anxiety for Electric Cars Is Overblown.”
The race to increase battery energy density and lifetime is one of the most well-funded efforts in the world. That’s because the ability to store more electricity in the same space is not just something EV makers will pay top dollar for. Cellphone and laptop makers and many others want it to.
So even as lithium-ion batteries continue their learning curve improvements, many companies are pursuing different battery chemistries, such as aluminum air and lithium metal.
Batteries have an anode (negative electrode) and a cathode (positive electrode) and an electrolyte, which conducts ions between the two and is typically a liquid. The lithium-ion batteries commonly used in EVs and cell phones, “use a variety of lithium-oxide compounds for the cathode, and a non-lithium material (usually graphite) for the anode.”
Lithium “is the lightest and most electronegative metal in the periodic table,” explains Qichao Hu, Founder & CEO SolidEnergy Systems Corp. But lithium metal is highly reactive with the liquid electrolyte, so “it was sidelined during much of the 1990s and 2000s and replaced with Li-ion batteries that do not contain lithium metal.”
But the “promise” of solid-state batteries, the journal Nature explained last year, “is that they will replace the heavy and sometimes dangerous liquid electrolyte” with a “lighter, more versatile solid alternative.” As one MIT materials scientist put it, “Imagine batteries that do not catch fire and do not lose storage capacity. That is the promise of solid-state batteries.”
And that’s why interest in solid-state batteries has soared. Indeed, the number of major journal publications related to lithium-metal batteries has increased 10-fold in the past quarter century.
Just last week, Boston-based SolidEnergy Systems announced it had developed a virtually “anode-free” lithium metal battery that was twice as energy dense but longer-lasting and potentially safer than lithium-ion batteries. The batteries replace the traditional graphite anode with a “very thin, high-energy lithium-metal foil.”
One advantage SolidEnergy Systems has is “the batteries are made using existing lithium ion manufacturing equipment, which makes them scalable,” as Technology Review explained. Ironically, after A123 Systems, “the well-known MIT spinout developing advanced lithium ion batteries, filed for bankruptcy,” SolidEnergy Systems was able to make use of their equipment.
A123 shows that the battery business is fraught with failure. It’s tough for startups to compete against all the big-name companies in the battery business. SolidEnergy Systems plans to start in one of fastest-growing niche areas requiring compact batteries — drones.
If SolidEnergy Systems or one of its many competitors succeeds — or if Li-ion batteries continue their steady progress — then you can expect to see 400-mile range EVs in the 2020s. And that will signal the beginning of the end of dominance by fossil fuel combustion engines in the vehicle market.