|July 31, 2015|
Breakthrough in Low Temperature operation of 2½nd Generation High Current Rechargeable Lithium Batteries
New battery chemistry extends the practical low temperature discharge range to -40°C
This technology was developed for a Norwegian company that did not go into production with their product, so the cells are not available. This project could be started again if the demand is large enough.
Although lithium ion batteries cannot be charged at cold temperatures they will not freeze at temperatures down to -40°C and can be discharged that low. The following curve is a test of our new low-temperature battery chemistry showing significant performance at -40°C
The average voltage during the discharge is 3.4 volts, giving an energy capacity of this cell at -40°C of 59 watt-hours (212,000 joules).
20 AH cell (nominal)
Charged at 20°C and 20 Amps to 4.2 volts, then held at 4.2 volts until the charge current drops to 0.5 Amps
Put into the cold chamber at -40°C and soaked for 2 hours
Discharged at a current of 1.5 amps (C/13), down to a termination voltage of 2.75 volts.
Measured capacity of 17.3 AH at -40°C
Measured capacity of 20.9 AH at +20°C
Low temperature capacity efficiency at -40°C is 82.7% compared to room temperature.
For battery management boards and chargers for these large lithium ion cells and packs go to http://www.powerstream.com/LLL.htm