Author Dr. Simon Madgwick of Nuvvon Inc.
In the post about 10-things (10 things about SSBs that you are often not told) Nuvvon highlighted key issues including safety, pressure, lithium compatibility and scalability. At that time Nuvvon were making small cells around the 100mAh range with modest cycle life & C rate but nonetheless truly solid polymer SSB and operating without compression or heating. 2-years on and here are the specs for 1Ah cells, and soon 5Ah and then 20Ah.
To recap: these cells are solid throughout including separator and catholyte; they operate without compression and without heating; they are lithium metal and high voltage compatible; and they are made on the existing Li-ion process using traditional Li-ion cell architecture.
1Ah is available with Lithium metal anode and graphite anode.
System: Solid-State Lithium Ion
- Cathode: NMC811
- Anode: Graphite
- Electrolyte: Polymer NUVVON-301
- Room temperature ionic conductivity > 10-3 S/cm
System: Solid-State Lithium Metal
- Cathode: NMC9
- Anode: Li-Metal
- Electrolyte: Polymer NUVVON-201
- Room temperature ionic conductivity > 10-3 S/cm
- Nominal Capacity = 1 Ah
- Nominal Voltage = 3.75V
- Energy Density
- Gravimetric
- Cell = 260 Wh/kg
- Stack = 297 Wh/kg
- Volumetric
- Cell Charged = 622 Wh/L
- Cell Discharged = 642 Wh/L
- Stack (Charged) = 730 Wh/L
- Gravimetric
- Current
- Maximum charge = 2C
- Max continuous discharge = 3C
- Pulse discharge = 5C
- Nominal Capacity = 1 Ah
- Nominal Voltage = 3.9V
- Energy Density
- Gravimetric
- Cell = 368 Wh/kg
- Stack = 418 Wh/kg
- Volumetric
- Cell Charged = 947 Wh/L
- Cell Discharged = 1,076 Wh/L
- Stack (Charged) = 1,156 Wh/L
- Gravimetric
- Current
- Maximum charge = 1C
- Max continuous discharge = 2C
- Pulse discharge = 4C
Energy density is at full SoC (most players don’t mention this and quote volumetric energy density in the uncharged state which is about 15% higher for lithium metal).
- Cycle Life 1500 Cycles at 1C/1C to 80% Capacity
- Operating Temperature
- Charge: 0 to 60°C
- Discharge: -20 to 60°C
- Operating Pressure
- Normal operation at ambient pressure
- Cycle Life 500 Cycles at 0.5C/0.5C to 80% Capacity
- Operating Temperature
- Charge: 0 to 60°C
- Discharge: -20 to 60°C
- Operating Pressure
- Normal operation at ambient pressure
Cycle life is quoted with C rate. Maximum C rates and Pulse discharge rates are given but this reduces life.
There are no hazardous additions or rare earth additions and there are no PFAs in the polymer electrolyte.
The naked cell is the finished cell – no external systems for pressure or heating or cooling.
Most polymer SSBs are semi solid (and the same for ceramic SSB). Not Nuvvon, which is solid polymer electrolyte throughout including the catholyte. So its even more impressive that Nuvvon cells operate without compression because fully solid usuaually means sulfide SSB which of course needs massive compression (5-10MPa).
- Weight (total) approx. 15g
- Weight (total) approx. 11g
When we look at these cells against the database we see quite an extraordinary performance, especially considering these are on the smallest capacity side.
In addition these cells have a number of benefits around cell safety, further posts exploring this with data are due.
Identical traditional cells of commercial grade (1Ah, Gr-NMC811). One used Nuvvon solid polymer electrolyte throughout (SPE) and the other used conventional liquid electrolyte.
The liquid electrolyte cell went BANG instantly when shorted by the nail but the Nuvvon SPE cell did not.
This was followed by an even tougher challenge: Lithium metal anode with NMC9 cathode. Still no reaction when the nail punched through the cell.
Cycling
Predicting 1500 cycles to 80% capacity. Note the Nuvvon cells with zero compression perform better that the Nuvvon cell in a clamp fixture.
These cells are not available on the open market, only to order in small batch for testing and validation.
See also: Cell Benchmarking, Solid State Battery