When I wrote about QuantumScape’s Raptor and Cobra manufacturing processes, I looked through all the slides from the company’s Q2 2024 earnings conference call, and one immediately caught my eye. It described the charging performance of the Alpha-2 prototype cells the solid-state battery (SSB) startup is building. In tests, they went from 10% to 80% charge in 13 minutes and 36 seconds. That puts them in a more realistic perspective on what they will and won’t do when they become available.
The fastest-charging battery-powered electric vehicle (Electric vehicle) currently on sale is the Porsche Taycan. According to its manufacturer, it can go from 10% to 80% state of charge (SOC) in 18 minutes. Most BEVs take more than 20 minutes to do the same, so QuantumScape promises to shave 5 minutes off what is already the best time around. While that sounds good, it’s not the best promise we’ve seen.
Polestar announced on April 29 that a Polestar 5 prototype went from 10% to 80% SOC in just ten minutes, thanks to StoreDot. The Israeli startup is developing Extreme Fast Charging (XFC) cells, and the Swedish brand is a major investor in the company. In other words, the first product to use these cells should come from Polestar. And that’s just part of the worries QuantumScape might have.
Photo: Callum and Nyobolt
Nyobolt revealed on June 28 that its niobium anode cell enabled its sports car prototype with a 35-kWh battery to go from 10% to 80% SOC in four minutes and 37 seconds. That's about a third of the time it took QuantumScape cells to reach the same SOC. Nyobolt did it with 350 kW (800V) DC fast chargers, which should be the standard for all BEV owners to get that kind of power. It’s worth noting that its battery pack is also quite small. I’ll try to get in touch with Nyobolt to clear up some doubts about this cell, but the fact is that it promises to be much faster than anything QuantumScape has to offer.
Samsung SDI and LGES have also joined the race. Both announced at the SNE Battery Day 2024 event that they are working on solid-state cells. Samsung said it would start selling its product in 2027, while LGES is expected to do so by 2030 with dry electrodes and solid sulfide electrolytes. QuantumScape often claims that these electrolytes or separators lack low and high voltage stability or adequate dendrite resistance. LGES and Samsung SDI have just warned that these cells are intended for premium and super premium cars because they will be very expensive to make. To address this issue, Samsung SDI said it is developing cells that take just 9 minutes to go from 0 to 80% SOC. They are also expected to last 20 years.
Finally, we have SVOLT and its Short Blade cells that can fully charge in 10 minutes (6C), meaning going from 10% to 80% SOC will take less time. All of these competitors promise to offer better charging times than QuantumScape’s SSB. That said, why should we wait for what the startup will eventually sell when it might already be obsolete by the time it’s ready for production?
Photo: QuantumScape
Ruggedness is one reason. QuantumScape said its cells can withstand 1,500 to 2,000 fast-charging cycles and still retain 80 percent of their original capacity. If a vehicle has a range of 300 miles, that’s 600,000 miles of life. Most BEV manufacturers will only replace a battery pack under warranty if its capacity drops below 70 percent. Cool, right? Well, Nyobolt said its cells can withstand 4,000 cycles and still retain at least 80 percent of their original capacity. Considering that the battery pack tested offers a range of “155 WLTP Procedure miles,” Nyobolt cells offer a lifespan of 620,000 miles, if not more. After all, they would simply be replaced after dropping to 70 percent capacity. But what about energy density?
Nyobolt cells use a common ternary cathode (with nickel, manganese, and cobalt, or NMC). This could make them heavier than a QuantumScape cell, which only features lithium metal as the anode and is “cathode agnostic.” This means they can use any cathode with their ceramic separator and still have lithium metal anode formation. This could also help improve energy density. In other words, a vehicle with QuantumScape cells has the potential to be lighter than one with Nyobolt cells.
Photo: Callum and Nyobolt
There you have it. QuantumScape cells promise fast charging. Even more, they promise to withstand fast charging without losing much of their original capacity. They also promise to be lighter, cheaper to make, safer (the ceramic separator doesn’t burn), and more energy dense than their competitors, many of which promise similar things. We’ll only know for sure which ones will actually do this when all these cells stop being wishful thinking and are actually available for automakers to buy. Hopefully, more than one will achieve their goals, which will determine which to use based on cost. The cheapest ones should win out.
As we’ve seen more than once, promises that never materialize or simply embarrass those who claim they’ll come true next year (every year) are nothing new in the automotive industry. Like Thomas, we need to see to believe anything. Fortunately, we have plenty of promises of fast-charging, rugged, and lightweight cells on the table.