Novel Battery Could Power Microdevices

Originally Published MDDI March 2003R&D DIGEST

March 1, 2003

2 Min Read
Novel Battery Could Power Microdevices

Originally Published MDDI March 2003

R&D DIGEST

Microscale devices are considered a promising field of research that will someday lead to advanced medical technologies, but they are still limited by their need for power. Narrower than a human hair, such devices could perform a range of vital functions—from drug delivery to monitoring vital signs. However, no existing battery can provide long-lasting power and fit inside these devices. 

Researchers at UCLA believe that a novel design for a lightweight, rechargeable battery, which is based on three-dimensional geometry, will provide power to devices that are too small to be powered by traditional batteries. "Our team of engineers and chemists are establishing the enabling science for a new battery that represents a real paradigm shift," says Bruce Dunn, a materials science professor in the UCLA Henry Samueli School of Engineering and Applied Science. For example, 3-D battery technology could be used to power implantable devices that deliver drugs or protect transplanted cells. Other devices could be used to automate blood, tissue, and cellular analyses at much lower costs than conventional techniques, the group speculates.

Traditional electronic devices, such as cell phones and handheld medical devices, use two-dimensional batteries with positive and negative electrodes stacked like sheets of paper. To increase battery power, more layers are added. But the added layers also make the battery bigger and heavier. Dunn suggests that although this may be appropriate for consumer devices, when such battery configurations are reduced to the size required for MEMS device applications, they lack the energy to do the job. 

The UCLA-led team proposes changing from two-dimensional electrode sheets to rods arranged in a three-dimensional array. In this configuration, hundreds of rods are stacked next to each other. Because each rod is only a thousandth of a centimeter in size, battery size remains compact and the distance the ions have to travel is short. Says Dunn, "A more efficient path for the movement of ions means less power loss and a longer-lasting battery." 

The group is currently designing a battery roughly 5 mm in size. The researcher explains, "We're going to use fairly well-known lithium battery materials. The hard part is fabricating them into a structure. That's where the real engineering emphasis will be." 

C.J. Kim, PhD, of UCLA's department of mechanical and aerospace engineering, is working with students to create silicon chips for use as molds. The electrode materials are placed in a mold and left to harden. The silicon mold is then etched away, leaving behind the 3-D battery structure. 

Dunn says it be another five years before 3-D battery designs are marketed. "The portable-power market is so vast that if we are very successful, I am sure our concepts and designs will be used to try to make 3-D power supplies." 

Copyright ©2003 Medical Device & Diagnostic Industry

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