25 micron polypropylene dry process (PP)
25 micron ceramic coated polyethylene wet process (PE)
Dreamweaver Silver 25 micron
Dreamweaver Gold 25 micron.
Starting electrical performance was nearly identical between the cells before testing:
Hard Short: The cells were shorted between their tabs. The cells all performed the same, with the anode tab (4 mm tab) getting red hot, and the cells slowly heating and internally gassing until the seal broke.
Overcharge: The cells were charged at 2C from 30% SOC. All uncoated cells failed at 5.55 V by outgassing, while the ceramic coated PE failed at 5.9 V. There were no flames, and the temperature rise was uniform between cells.
Hot Box: Cells made with PP and PE/ceramic separators both had fast temperature rise and they also both experienced a catastrophic short after around 20 minutes. DWI Silver and Gold cells maintained operational voltage for 1 hour and survived without shorting. The short for the PE/ceramic cell occurred with onset at around 140 C, and for the PP cell at around 145 C. Both of the DWI cells rose to 170C, the oven temperature, without experiencing a short.
Nail Penetration: Cells made with both PP and PE separators dropped immediately to a persistent 0V along with faster and higher temperature rise (up to 115 C) than the cells made with Gold (40 C) and Silver (60 C). The Dreamweaver cells, on the contrary, experienced only a small voltage drop of approximately 100 mV, with a slow rise thereafter as the cell discharged. The DWI cells continued to function throughout the test and retained 2/3 of their charge and capacity after completion of the test.
Shutdown Function: In no test was a shutdown function observed to improve the performance in any of the cells.
