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Challenge Technology developed for one use maysometimes be applied successfully in another.The U.S. Department of Energy first spon-sored research on the valve-regulated leadacid (VRLA) as an energy storage device forelectric utilities. To ensure uninterrupted elec-trical power during peak periods, utilitycompanies store energy during periods of lower demand. The high-performance, long-lived, low-maintenance VRLA battery is anideal choice for this purpose. Now this tech-nology is being applied to electric vehicles.

Technology Description The sealed VRLA battery is a closed system in which the quantity of electrolyte is limited, but the gases resulting from energy production arerecombined to be reused instead of beingreleased to the atmosphere. Because the elec-trolyte is recycled, there is no need to add water to the batteries. Excess gas pressure that may build up inside the battery is releasedthrough a simple regulating valve to ensurethat structural integrity is not compromised.

Accomplishments s The VRLA battery concept was developed

and rigorously tested to confirmperformance. These tests demonstrated theeffectiveness of the valve-regulated concept compared with flooded, vented cells. When

tested in large modules and packs, VRLAbatteries showed excellent performance.

s VRLA batteries were adapted for use inprototype and early limited-productionelectric vehicles in the late 1980s and early1990s because of their low maintenanceand availability. This application facilitatedfield demonstrations and electric vehiclesales.

Commercialization s The VRLA concept has been adopted by

industry and widely commercialized in a variety of applications. The U.S. lead acbattery industry continues to maintain astrong position in this technology.

s VRLA batteries were introduced in auto

biles in 1978 for starting, lighting, andignition.

Benefits s The relatively low cost of VRLA batteri

reduced the cost of electric vehicles, whis helping introduce markets where ranglimitation is not a problem.

s The electrode materials and thermoplasticase of VRLA batteries can be completerecycled with current technology.

Valve- Regulated Lead Acid Battery

April 2001 http://www.ott.doe.gov/success.html

Battery technology moves from power stations tothe open road

Contact Kenneth HeitnerManager, Advanced Electric Vehicle Batteries

202-586-2341202-586-1600 faxkenneth.heitner@hq.doe.gov

Valve- Regulated Lead Acid Battery

Valve-regulated lead acid batte

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Future Activities The industry will continue to use VRLA batteries for appropriate applications.

Partners in Success s Argonne National Laboratory

s Exide Technologies

s Johnson Controlss Sandia National Laboratories

http://www.ott.doe.gov/success.html