Solid-state batteries have been promised by major car manufacturers for quite some time now. Toyota, one such carmaker that invests in the development of this technology, intends to launch a hybrid car with solid-state batteries by 2025. Solid-state batteries are the foremost in terms of battery technology for the EV future coming to fruition faster than a lot of legacy automakers expected.

This battery technology should deliver a longer life span than currently used lithium-ion batteries, more range, and faster charging times, among other benefits. Since legacy automakers are banking on this technology to hit mass markets by 2025, people waiting for some nuances of owning an EV to be addressed to pull the trigger on buying one should be excited. But why wait until 2025? What are the challenges preventing the widespread use of solid-state batteries right now? Is the advancement toward this technology noticeable, or is it stuck in time? Here’s what’s been going on with solid-state batteries.

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There Are Still Tricky Issues For A Viable EV Solid-State Battery

The challenges posed by the use of solid electrolytes versus the current liquid electrolytes in lithium-ion batteries are many. The stability of these batteries is usually poor, and their high surface resistance limits their output and concurrently, their applications. But advancements are, in fact, happening, and on more than one front. From companies like battery manufacturer QuantumScape to renowned universities all over the world such as Harvard in the States, as well as Tokyo University of Science, among others, from legacy and BEV carmakers to even NASA, many institutions are working on improving the technology, fix its issues and make the leap toward mass-market application.

The widespread commercial application of solid-state batteries is currently faced with a still unknown challenge. Exactly how the surface resistance shown by these batteries happen continues to be something that evades researchers’ knowledge, and is linked by them to a phenom called the Electric Double Layer (EDL). This EDL effect happens at the solid/solid electrolyte interface, an issue that for obvious reasons doesn’t happen with liquid-chemistry batteries such as the ones used in BEVs and hybrids today.

Related: 10 Electric Vehicles That Need Solid-State Batteries ASAP!

Solid-State Can Be A Game-Changer, But There Are A Few Milestones To Be Reached

A comparison between a Lithium-ion battery on the left and a charged Lithium metal Solid-state battery from QuantumScape
QuantumScape via YouTube
A comparison between a Lithium-ion battery on the left and a charged Lithium metal Solid-state battery from QuantumScape showing the energy density potential of the solid-state battery.

This unpredictable EDL effect is one of the main reasons solid-state batteries aren’t available on present-day EVs. But as researchers' optimism remains resilient and more resources are put into it, it seems reasonable to believe the needed breakthroughs for solid-state batteries will happen in the coming years, if not sooner. All this research and development is, after all, highly fueled by the gigantic EV market in the world today. As the saying goes, ‒ money talks ‒, and there is a lot of it to be made with suitable solid-state batteries.

Different approaches to building a solid-state battery are being tested and the EDL effect is being reduced, to the point where it is becoming more predictable. But there are other problems solid-state technology faces like the further development of current liquid-chemistry batteries. CATL, the world's largest battery manufacturer has experimented with sodium-ion batteries, as well as the U.S. Department of Energy’s Pacific Northwest National Laboratory. Sodium has some advantages over lithium-ion batteries, one of them being the high availability of the material over lithium, but it also has some trade-offs. A hybrid battery pack that uses sodium as well as lithium-ion is also being tested by CATL and could make batteries more affordable and better overall for current BEVs. This solution could put solid-state batteries in check should their cost be prohibitive.

Related: Will Solid-State Batteries Make Tesla's EV Batteries Redundant?

Conventional Battery Technology Still Has Room For Improvement

An illustration of BYD's Blade Battery
BYD
BYD has pioneered its own battery design called Blade Battery.

Battery technology has improved tremendously since the beginning of the current BEV revolution and their cost, which accounts for a large portion of a BEV’s price has decreased proportionally. BYD, the largest EV automaker in China, far ahead of Tesla in sales in that market, has plans to tackle the EV market Stateside, and that promises to bring EV prices further down, much closer to current ICE vehicles, making the transition towards a BEV easier for customers. BYD already supplies a few cities in the U.S. with electric buses made in a factory built several years ago in Lancaster, California. They’ve been analyzing the American market for some time now and when they come with all their resources, they’ll do so with a sound strategy that could really shake things up in the EV market in the US.

For a full ICE to BEV transition to take place as fast as possible, something that interests society as a whole particularly due to environmental and health concerns, EVs need to be affordable, and that’s why batteries are so important. They’re expensive, and making them cheaper, either by scaling production, or finding ways to make them more energy dense, enabling the use of smaller battery packs without compromising range, or even by transitioning to a whole new technology such as solid-state batteries, is key for a sustainable future.

Considering the advancements that have been shown so far, along with the expectations and plans of companies and research institutions for the near future, solid-state batteries should indeed become viable in the next couple of years. What remains to be seen is just how much viable they will be compared to already existing batteries that will also be improving as time goes by. The technology will be there, but which one will win the mainstream is still anybody’s guess.