Jagdeep Singh compared solid-state batteries to skyscrapers. QuantumScape’s CEO said people now know how to build them in Manhattan or any other major city in the world. However, it took cement and steel to get things started. This is what QuantumScape believes to have created for SSB (solid-state batteries): their very foundation.
Although it involves way more than that, you can summarize this foundation as the ceramic separator the company developed over the last ten years and after more than 2 million tests. All other separators so far allowed dendrites' formation, which ruined the cells after a few cycles.
Singh did not reveal what this separator is. What he could disclose is that it endures more than 800 cycles with over 80 percent of the original battery capacity. Translated to automotive terms, it implies these batteries will be good for more than 240,000 miles when they are ready.
Singh believes QuantumScape will be able to offer these batteries within the deadline it already presented: 2025. Luckily, we will see them around by 2024, but not earlier than that. This is the time the company needs to solve some of the technical difficulties it still has, such as multilayering and stacking these pouch cells together.
The video below shows what the QuantumScape SSB is and how it works:
Keep in mind that this is just for educational purposes. The ceramic separator is thinner than human hair, and the test pouch cells are not very thick. They are 70 millimeters wide and 85 mm tall. They are also anodeless, just like the solid-state cells created by the University of Michigan.
This is not the only coincidence the QuantumScape SSB has with the concept developed by Jeff Sakamoto and his team. Both cells start to work after lithium plating that happens between the ceramic separator and a metal foil – which QuantumScape names as “anode electrical contact – the first time they are charged. There’s no excess lithium, which would decrease energy density.
Unfortunately, the University of Michigan SSB managed only 50 cycles. Sakamoto said he had to solve the swelling and find a better cathode technology. QuantumScape’s cell expands in a uniaxial direction, so the company believes it can cope with the swelling with volume compensation methods. Regarding the cathode, Singh said QuantumScape’s battery uses mostly the same nickel rich cathode now present in regular lithium-ion cells.
In practical terms, the new SSB works well from -25ºC (-13ºF) up to 60ºC (140ºF), does not need more than 3 ATMs of pressure, and stands high voltages with no damages to the ceramic separator. That implies it can fast charge from nothing to 80 percent of capacity in just 15 minutes, equivalent to 4C. The QuantumScape cell already endured 25C with no issues, which implies it could theoretically charge in just 2 minutes – like the PJPEye single carbon electrode cell.
For the ones that thought Volkswagen did not support QuantumScape’s findings, two company executives were at the call and confirmed the results presented by the SSB startup. When any car is ready to use these batteries, expect it to be from the German group.
That will happen with the first production facility, which will be built by a joint-venture between QuantumScape and Volkswagen. It will be able to produce 1 GWh per year in batteries. The second step will be a factory for 20 GWh.
Among the specialists gathered by QuantumScape was Stanley Whittingham. If you are not familiar with the man, he is the co-developer of the lithium-ion battery with John Goodenough and Akira Yoshino. In other words, a recipient of the 2019 Nobel Prize in Chemistry.
Whittingham said he was a skeptic and that you should never believe battery breakthroughs, but that he was confident QuantumScape achieved what he and his Nobel Prize peers tried decades ago: to have a battery with lithium metal.
Other specialists were impressed by how fast the SSB can charge, how energy-dense it is, and how much lighter and cheaper it will be to manufacture. All of them agreed that what the company presented was not something outstanding in a single aspect. Rather, it was a solution that addresses all automotive requirements for a battery: standing high voltages to fast charge, lasting long, not having excess lithium, and working well at really low temperatures.
Without being specialists, we can’t wait to see QuantumScape delivering its first SSBs to Volkswagen or any other car company that manages to buy them. Unlike people that build houses with wood or clay, we know what the cement for better batteries will be.