By Courtney E. Howard
SAN DIEGO, 12 March 2008. The afternoon's "Power and Thermal Management" sessions at the Military & Aerospace Electronics Forum began with a talk on today's battery options, and their inherent pros and cons.
Dr. Novis Smith, VP of technology at LithChem Energy in Folcroft, Pa., presented a talk titled, "Innovative Power Solutions for Warfighter Systems."
Today's rechargeable battery choices include: SLA, NiCd, NiMH, and Li-ion. Li-ion is more expensive, but it is roughly half the weight of its nearest competitor, NiMH. "It's all about energy density," Smith says; this statement is especially true for the military and aerospace market.
What does it cost to run Li-ion batteries, which are the highest in cost of current rechargeable battery options? "Li-ion comes out around 50 cents per watt hour," notes Smith.
"The warfighter needs more energy," Smith acknowledges. "The load is too much to carry. Batteries are expensive, get in the way, and are problematic. The basic need is for more rechargeable energy."
The best long-term goal possible for lithium battery technology is 381 Wh/kg (watt hour per kilogram), roughly three times what is available today, Smith says. Fuel cells, another energy storage option, deliver up to 500Wh/kg, but they are slow to deliver and some consider their future uncertain.
Primary batteries (non-rechargeable) give the maximum energy density, but they have drawbacks in terms of size, weight, waste, and environmentals/temperature.
"What can we hope for in the next five years," Smith explains, "are rechargeable batteries offering 240 to 300 Wh/kg—a rechargeable battery half the size or twice the energy offered by the 2590 used today."
