100% Solid-State EV Batteries Seal The Deal: No More Gasmobiles

The US has taken a U-turn on zero emission mobility, but the rest of the world is moving on. A case in point is BMW Group, which is moving forward with plans to introduce 100% solid-state EV batteries to the auto-buying public. Progress has been slow, but a key test is under way right now in the firm’s home country of Germany, deploying battery technology from the Colorado-based startup Solid Power.

Solid-State EV Batteries Are Coming For Your Fossil Fuels

EVs have already cracked into the mainstream automotive market, so it’s fair to ask what’s wrong with the conventional liquid-electrolyte batteries commonly used in EVs. The answer is nothing. In surveys, individual EV owners and commercial fleet operators both report they are overwhelmingly satisfied with the EV experience. Globally, most EV makers (though not all) also continue to enjoy rising year-on-year sales.

Still, the auto market runs on shiny new objects. All-solid electrolytes can pack more energy into a smaller, lighter battery, providing more range in the same footprint as a conventional battery.

Conversely, the energy density factor can enable automakers to offer smaller, lighter EVs with smaller batteries that provide a reasonable amount of range. Additional benefits include reducing the cost of materials and manufacturing while also providing automotive designers more flexibility to tempt car shoppers with new style concepts.

Supply chain benefits also come into play including diversification, onshoring, and reducing if not eliminating ethical complications and toxic materials.

The Sulfide Solution

Solid-state EV batteries are already beginning to emerge on the market. However, the early iterations combine solid with semi-solid or liquid electrolytes, or some variation thereof. BMW is aiming for the more elusive prize of 100% solid-state EV batteries.

Managing the expansion and contract of a solid material is one among many hurdles standing between battery researchers and all-solid electrolytes, and Solid Power has plenty of experience in that area. The company launched 14 years ago in Colorado, building on research conducted at the University of Colorado Boulder.

The solid state wheels have been turning since then. Solid Power first caught the eye of BMW in 2016. When Solid Power went public in 2021, both Ford and BMW signed on as investors. The company also has a relationship with the Korean battery manufacturer SK On (see more Solid Power background here).

Solid Power has adopted sulfides (derivatives of sulfur) as the pivotal input for its solid electrolyte. In addition to pushing volatile liquids out of the picture, the sulfide material eliminates the polymer separator typical of lithium-ion batteries.

“Solid Power’s sulfide-based solid electrolyte is the key ingredient that powers Solid Power’s All-Solid-State Battery Platform technology,” the company explains. “This thin, solid layer acts as a barrier to keep the anode and cathode from touching one another, which would short the battery. It also acts as a conductive electrolyte.”

“We expect to scale electrolyte production to power 800,000 electrified vehicles using our all-solid-state battery cells annually by 2028,” Solid Power also states on its website. 

The Long Road To Solid-State EV Batteries

The figure of 800,000 EVs per year by 2028 sounds rather optimistic at this point, but the latest news from BMW indicates that the road-testing phase is well under way.

“The BMW Group is bringing large-format, pure ASSB [All Solid State Battery] cells from Solid Power to its test vehicle, a BMW i7, which is being operated in the Munich area,” BMW Group announced earlier this week, citing the higher density of solid-state EV batteries as the primary benefit.

“With a higher energy density compared to current battery technologies, ASSB batteries have the potential to achieve longer ranges in vehicles without the disadvantages with regard to the weight of the overall storage system,” BMW emphasized.

There is still a long way to go. BMW notes that the test period will take place over the coming months, describing the battery in the i7 test vehicle as a “concept battery,” that combines “new, innovative module concepts” with the proven architecture of prismatic cells, referring to a rectangular shape first introduced in the 1990s.

BMW adds that it will be paying close attention to expansion management during the road tests. Among other elements under observation, BMW also cites controlling the operating pressure and adjusting the temperature.

“Further development steps are required to implement ASSB technology in a competitive overall storage system,” the company advises.

Next Steps For Solid-State Batteries In The US

Anticipating that development will proceed apace, BMW is planning to run a prototype line in Germany at its Cell Manufacturing Competence Center in Parsdorf, under a license from Solid Power.

As for when those new EV batteries will hit the road in the US, that’s a good question. Solid Power is not the only US firm working to bring 100% solid electrolytes to the EV world, but the company does lay claim to the pole position. “Only Solid Power develops and produces sulfide-based solid electrolytes at pilot scale and tests in large format cells produced on a scalable production line,” the company states, referring to its facility in Colorado.

Keep an eye on Ford for further activity here in the US. Aside from its interest in Solid Power, in 2021 Ford shelled out the big bucks for new factories to grow its output of EVs and EV batteries. Earlier this week, however, The Wall Street Journal observed that Ford has scaled back its electrification plans. SK On, though, is continuing its efforts to fine tune sulfide-based solid state batteries.

In another interesting development, last September Solid Power celebrated its selection for a $50 million grant from the US Department of Energy, subject to negotiation. “With this project, Solid Power intends to install the first globally known continuous manufacturing process of sulfide-based solid electrolyte materials for advanced all-solid-state batteries (ASSBs) and expand its electrolyte production capabilities at its Thornton, CO facility,” Solid Power explained, adding a continuous manufacturing process will enable it to produce the new electrolyte at a “significantly lower cost, compared to today’s process.”

No word yet on those negotiations, but apparently Solid Power has a fallback plan if the Trump administration snatches the funding football away. In a press releases dated September 20, the company stated that it “does not anticipate any DOE funding to have a material impact on its financial outlook for this fiscal year, which it last provided on August 6, 2024.”

Photo (cropped): BMW is putting new sulfide-based, solid-state EV batteries from the US startup Solid Power through its paces in a BMW i7 EV (courtesy of BMW Group).