Most modern EVs run on lithium-ion batteries, but the emerging technology of solid-state batteries is radically superior.
The shift from internal combustion to electric vehicles will be a multi-decade process. Today, there are two major hurdles: a lack of infrastructure (both in terms of charging networks and also grid capacity) and the current limitations of EV battery technology. One of the main reasons consumers remain reluctant is range anxiety, basically how far an EV can travel on a single charge.
Lithium-ion batteries are the most common type of rechargeable battery used in hybrid and electric vehicles thanks to the relatively good mix of rechargeability, longevity, and power density. As good as lithium-ion batteries are, the typical EV’s range is still below, and sometimes well below, that of an equivalent internal combustion vehicle. Coupled with the lack of infrastructure, it’s natural that car buyers might worry about getting stranded on the side of the road.
However, the nascent technology of solid-state batteries promises to vastly improve on current lithium-ion technology and accelerate widespread EV adoption.
To understand why solid-state battery technology is so significant, it’s necessary to consider the differences between them and lithium-ion batteries. Your typical 12-volt lead battery, nickel-metal hydride batteries, and lithium-ion batteries all have a liquid electrolyte that mediates the flow of current between the anode and the cathode (the negative and positive electrodes of the battery). A solid-state battery replaces that liquid electrolyte with a solid one. Here’s why that matters.
While lithium-ion batteries have spawned the current generation of jaw-dropping EVs, they’re far from perfect. Lithium-ion batteries, though decently energy-dense, tend to be heavy. As a consequence, there are diminishing returns on their efficiency. The more range you want an EV to have, the more batteries you need to pack on. But the more batteries the heavier the vehicle gets, thus requiring more energy to move the same distance at the same speed.
Lithium-ion batteries are also volatile. Damage and degradation can lead to swelling, leaks, fires, and even explosions. Electric vehicle fires are notoriously difficult to put out, posing a new and unwelcomed challenge for fire fighters.
And finally, lithium-ion battery charging takes a long time and, like your cell phone, degrades the battery pack over time. Part of EV adoption will mean getting closer to the current convenience of gas cars, where filling up takes just a few minutes. As lithium-ion batteries are charged and recharged, they lose their capacity to hold a charge, potentially limiting the lifespan of EVs.
The solid-state battery solves or alleviates most of the drawbacks of lithium-ion technology. By comparison, solid-state batteries are much more compact, reducing the distance between cells from 20-30 microns down to just three or four microns. This means carmakers have the option of extending the ranges of EVs by adding more battery packs or lowering their price by including fewer. Solid-state batteries could double current EV ranges and make them equally affordable compared to traditional gas cars.
The benefits of solid-state batteries don’t stop there, either. They’re also more stable, largely eliminating the risk of fires, leaks, and explosions. Charging times are also reduced, with current goals aiming for an 80% charge in approximately 15 min. Battery degradation is also significantly reduced. Solid-state batteries even address how extremes of hot and cold weather negatively affect EV range.
This all doesn’t mean solid-state technology is easy. First, solid-state batteries run into a problem known as dendrites, leaf- or thread-like structures than form on the anode. These dendrites can grow into and even cross the electrolyte into the cathode, damaging the battery. Dendrites have been on of the biggest challenges to solid-state technology, but one many researchers and scientists hope to have finally solved.
Also, despite the difference in name, many solid-state batteries still use lithium as the anode. Therefore, the environmental concerns surrounding lithium extraction remain (though lessened somewhat due to the longer life of solid-state batteries).
Switching from lithium-ion to solid-state batteries will be a long but ultimately fruitful process. As companies have been able to scale their manufacturing and procurement processes, the price of lithium-ion batteries has steadily declined, falling 89% over the period between 2010 and 2020, according to Bloomberg News. A similar decline is likely in the case of solid-state batteries, though that’s a matter of major investments across the sector.
And those investments are being made to the tune of billions of dollars by players large and small.
Toyota (working with Panasonic) announced last month that they were investing an additional $13.6 billion in battery technology, with a large portion going toward solid-state batteries. The company even unveiled a new version of their LQ concept car (from 2019) running on solid-state batteries. Toyota hopes to have solid-state batteries in cars by 2028, with the first to arrive in hybrid vehicles.
Samsung says it’s solved the dendrite problem by using a silver-carbon anode. They’re projecting their new battery will be able to offer a range of some 500 miles and retain its capacity for over 1,000 charges, equivalent to 500,000 miles.
Quantum Scape (with investors including Volkswagen) plans for their solid-state battery to charge 80% within 15 minutes and retain at least an 80% charging capacity for over 800 charges. Volkswagen hopes to get these batteries to market by sometime in 2024.
Bolloré, who currently supply batteries for Mercedes-Benz buses, is already producing lithium-metal polymer batteries at have an 80° operating temperature, allowing it to work with less regard for ambient temperature.
These and dozens of other companies are hard at work getting solid-state batteries from the drawing board to a garage near you.