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Agency: National Security Agency

Technology: Battery Isolator and Switch (BIAS)

Summary: High-energy batteries can be dangerous. Mishandling of modern batteries has caused fires and explosions, as well as serious personal injury. Putting multiple batteries in parallel to increase operating life is a common battery design error. The most common method for safely connecting parallel batteries, diode isolation, is inefficient because of the diode’s forward voltage drop. It also has no easy way to tell how much energy remains in the battery. The BIAS system uses a low loss analog switch to connect one battery string at a time, which prevents dangerous circulating currents. The system can report which batteries have been used and which are still fresh, giving a rough "gas gauge" of how much energy remains.

Potential Commercial Applications:

Any system that needs reliable battery power could benefit from this system, such as: systems where power failure would be catastrophic, like radio-controlled model aircraft, where the main battery would last for several flights, and the backup battery would need only the energy to finish the present flight. An interlock would be added in this case to prevent taking off again until the batteries were charged or replaced. Medical uses could include I.V. pumps and portable defibrillators. Unattended systems such as weather stations and sonobouys could use both the high efficiency and the "gas gauge" functions. Finally, emergency response vehicles often have redundant ignition systems; this would give them a redundant battery supply.

Opportunity: Available for licensing.

Contact: Please express your interest in pursuing this technology by writing to the:

National Security Agency

NSA Technology Transfer Program

9800 Savage Road, Suite 6541

Fort George G. Meade, MD 20755-6541

For more information, view the NSA’s listing for the technology.

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