Test Data Notes

P. McGill
20Dec13

* Data files were recorded with a DATAQ Instruments model DI-718Bx 16-channel Ethernet data recorder (http://www.dataq.com/products/hardware/di718Bx.htm).

* Data files can be viewed with the free WinDaq Waveform Browser (http://www.dataq.com/products/software/playback.htm).

* Test descriptions:
Test 1 - Data recording test with heater on dummy 18650 cell made from cylinder of stainless steel. Only Cell 1 Temp and Chamber Pressure were recorded.

Tests 2 thru 6 - Single-cell thermal runaway tests, heating NCR18650B cell to failure.

Test 7 and 8 - Two-cell thermal runaway propagation tests, with cells positioned end-to-end. Nose of heated cell was 5 mm from tail of non-heated cell.

Test 9 - Two-cell thermal runaway propagation tests, with cells positioned end-to-end. Nose of heated cell was 65 mm (one cell length) from tail of non-heated cell.

Test 10 - Two-cell thermal runaway propagation tests, with cells positioned end-to-end. Nose of heated cell was 32.5 mm (one-half cell length) from tail of non-heated cell.

* Signal conditioning modules installed in Dataq DI-718BX data recorder for thermal runaway testing:
Ch 1 - 8B47K-04 "Isolated Linearized TC Input", type K thermocouple input, 0 to 1000 degC
Ch 2 - empty, as slot doesn't work for thermocouples in this particular unit
Ch 3 - 8B41-03 "Isolated V Input, Wide BW", +/- 10 V
Ch 4 - 8B41-03 "Isolated V Input, Wide BW", +/- 10 V
Ch 5 - 8B41-03 "Isolated V Input, Wide BW", +/- 10 V
Ch 6 - 8B41-09 "Isolated V Input, 1 kHz BW", +/- 40 V
Ch 7 - 8B47K-04 "Isolated Linearized TC Input", type K thermocouple input, 0 to 1000 degC

* Windaq channel assignments
Ch 1 - Cell 1 (heated cell) temperature (0 to 1000 degC)
Ch 2 - Cell 2 (non-heated cell) temperature (0 to 1000 degC)
Ch 3 - Chamber pressure (0 to 10 PSIG)
Ch 4 - Cell 1 (heated cell) voltage (0 to 5 VDC)
Ch 5 - Cell 2 (heated cell) voltage (0 to 5 VDC)
Ch 6 - Heater voltage (0 to 40 VDC)

* Heater was 30.5 inches of 24 AWG NiCr wire, of which 24 inches were wound around the test Li cell. At 315 degC, resistance of wire is 1.76 ohms/ft, or 3.52 ohms total.

* Heater power at Li cell varied for tests:
Tests 1 and 2 - 29 W
Test 3 - 26 W
Tests 4 thru 10 - 19 W

* Significant findings from testing
- Gas temperatures can reach almost 1000 degC
- Cells casings don't always fail at vent
- Failure can propagate to another cell 32 mm away in somewhat open environment
- More gas is released for NCR18650B than cells tested in literature
- Ejecta from cell can include not just ash, but large pieces of metal electrodes
- Polyfuse CIDs will fail as cell temperature is increased