While we’re still absorbing the Dodge Charger Daytona EV, the all-electric version of the iconic Charger nameplate, Stellantis has decided that it’s a good time to start thinking about a new battery technology to go along with its still-very-new electric muscle car. That fresh technology? A solid-state battery—the holy grail of battery tech of sorts—that promises more power, faster charging, and improved energy density without the safety drawbacks of liquid-electrolyte lithium-ion batteries. Don’t start cheering yet—there is some bad news.
If you’re new to the EV space, first, welcome, second, you’re probably curious as to what the heck we mean by “solid-state” batteries. We have a great explainer here, but the shortish answer is that this new technology seeks to remedy a big problem with most of today's lithium-ion batteries. Their electrolye is an organic compound that is itself highly flammable, because it contains the O2 molecules it needs to burn within the electrolyte. That means they don't even need air to combust, which makes them devilishly difficult to extinguish once they catch fire. Solid-state batteries do away with these electrolytes, and while some use a polymer or gel electrolyte that is not entirely "solid," they still largely eliminate that flammability problem.
It's a Battery FEST
The company behind the battery technology here is Factorial, Inc, a battery builder that started creating new technology as part of Cornell University before being spun off in 2013. Since that start, it’s attracted the likes of Mercedes-Benz, Stellantis, and Hyundai Motor Group due to its development of solid-state batteries. While both Stellantis and Factorial call the Factorial Electrolyte System Technology (FEST) a solid-state lithium-ion battery, it’s not a full solid-state and their website makes a call to this, calling it instead a “quasi-solid” electrolyte.
Before this announcement by Stellantis and Factorial, we spoke to people at the battery maker to find out just what they are using around this time last year. At the time, they weren’t willing to go into detail on just what FEST uses in place of that traditional wet electrolyte. Factorial also mentions a “high-capacity” cathode (the “negative” charge side of the battery) and they were even less forthcoming on what that is. Today’s announcement offers no further explanation on what FEST really is.
At the time of that previous announcement, test samples of the battery were being shipped to Stellantis, Hyundai Motor Group, and Mercedes. Now, nearly a year later, Stellantis is confident enough in FEST that it has announced that the 2027 Dodge Charger Daytona will feature this new battery tech, which will boast an energy density of around 177 Wh/pound.
Just How Significant Is “177 Wh/Pound?”
If true, that is a significant jump in energy density, as the best liquid-electrolyte lithium-ion batteries using conventional Nickel Manganese Cobalt (NMC) chemistry are around 70 to 100 Wh/pound right now and Lithium Iron Phosphate (LFP) is around 40 to 60 Wh/pound. To help put that in perspective, the average lead acid battery weighs about 40 pounds for an average energy density of about 30 Wh/pound for its average 1.2-kWh capacity.
That means that a FEST battery of the same weight would have almost 7 kWh of capacity. If you wanted the same 100-kWh capacity of a Tesla Model S, a FEST battery might therefore weight around 565 pounds, nearly half the 1,000 to 1,377 pounds these batteries are reported to weigh, according to many reputable sites on battery recycling.
More “Bang” For Your Electric Buck
The other advantage of these new Factorial FEST batteries are their discharge rates. If you’re unfamiliar with how charge and discharge rates are explained, they are “C-rated” and is related to how fast a battery can charge or discharge when either is demanded. A 1C battery can fill or dump its full capacity in an hour, and it is possible to see a different C-rating for discharge and recharge on the same cell. The higher the number, the faster it can do its thing. Your typical LFP battery can charge at 1C but rarely these can discharge as high as 25C. These barely exist outside of labs, and most commercially available LFPs are around 2C. NMC, the most popular chemistry of Lithium-based batteries, can charge and discharge at 1C while some can do a 2C discharge.
Factorial’s FEST battery cell is capable of up to a 4C discharge rate, which means the battery is losing less power from itself when an EV demands more power. It’s something you may potentially feel if you’re in tune with your acceleration rate versus pedal movement. For the average buyer, they probably won’t.
As far as recharge is concerned, neither Factorial nor Stellantis gives us a hard number but states that it only takes 18 minutes to go from 15 to 90 percent for its 77-ah cell. Doing some calculation, that 18 minutes puts it somewhere between 3 to 4C for recharging, a very impressive number and something that does bring DC fast charging closer to, say, the time it takes to fill a gas or diesel fuel tank. The other good news is that Factorial has demonstrated that it can do this easily for over 600 cycles of discharging and recharging without issue and do so between -22 to 113 degrees. Those ranges are far better than what any current NMC and LFP battery can do today as most will significantly slow down at below zero temperatures.
The Next Step
Now, Factorial and Stellantis are working together to bring these FEST cells to commercial production. Both manufacturers are working together to create the right pack design for these cells. While it may seem like a no-brainer to just put the FEST cells into existing packs, remember that these cells have a much larger energy density than the NMC cells currently used in their all-electric Dodge Charger and Jeep Wagoneer S. They will not only require fewer cells for the same capacity (thereby reducing weight overall) but can now also package them to improve vehicle weight balance. It may also be possible to reduce the pack capacity thanks to the weight loss and that will be another thing that both Stellantis and Factorial will need to consider.
Now for the "But"
While it’s possible we’ll see this tech on a 2027 Dodge Charger Daytona, as Stellantis states, it’ll only be in a small demonstrator fleet. The other issue is that the information on these FEST batteries from Factorial is so limited, it’s difficult to judge if what’s being promised is feasible for imminent mass production. Add in the hiccups that Dodge and Jeep are facing with the debuts of their all-electrics (the Daytona and the Wagoneer S), we can’t help but question the 2026 calendar year deadline that Stellantis has set.
However, if this truly comes together and all the numbers and information we do have proves out, this is a significant step in battery development. It wouldn’t just be a positive (no pun) for battery electric vehicles (BEVs) but anything that uses a lithium-ion battery. And it might lend further credence to Sandy Munro's assertion that solid state batteries could be "the kiss of death for gasoline and diesel."
