This is an April 20, 2021 article about the sudden appearance of ‘Factorial Energy’ in the race to produce an ASSB using a proprietary polymer separator
   Battery Startup Comes Out of Stealth to Seize On Investor Frenzy - Bloomberg
    QuatumScape is mentioned a couple times in the article.
     There are five metrics on which a battery is judged:
 - how much energy it packs, 
 - how fast it charges, 
 - how many charge-discharge cycles it lasts, 
 - how safe it is, and 
 - how much it costs.
  Factorial’s current batteries reach energy density of 350 watt-hours per kilogram and 770 watt-hours per liter. The company’s aim is to reach 400 Wh/kg and 1,000 Wh/l.. But not much better than existing L-ion technology 
    Factorial’s battery can do up to 460 charge-discharge cycles before its capacity falls below 80%. That’s more than what Solid Power promises with 250 cycles, but less than QuantumScape at 800 cycles.
    It looks like QuantumScape, has the a very big war chest with $1.5 billion compared to the other ASSB startups.
    Factorial started internally testing batteries with 40 amp-hours of capacity, about 10 times the size of a smartphone battery. That’s double the 20 Ah battery that Solid Power has built and many times the size of the largest battery QuantumScape has disclosed. (The size of a QuantumScape’s disclosed battery does not bother me too much since the industry is very secretive about their research.  CARKEY)
    solid-state battery partnerships:
 - Toyota Corp. is working with Panasonic, 
 - Volkswagen AG with QuantumScape, 
 - General Motors Co. with Solid Energy Systems, 
 - Ford Motor Co. with Solid Power and 
 - Mercedes Benz AG with Hydro Quebec
  Solid-state batteries are set to see rapid increase in demand after 2030, eventually outpacing current lithium-ion batteries |