Wayne State research team creating millimeter-scale lithium-ion battery for autonomous applications


Researchers in the Wayne State University College of Engineering are developing the world's smallest high-temperature lithium-ion rechargeable battery, capable of powering miniaturized autonomous and electronic devices at wide operating temperature ranges varying from room temperature to 125ºC.

Many robotic and sophisticated miniature applications require nimble movements in confined spaces, coupled with daunting power requirements. Additionally, the currently available commercial batteries are unsafe beyond 85ºC - this limit dips further for rechargeable systems. A team from the lab of Leela Arava, Ph.D., associate professor of mechanical engineering at Wayne State, is fine-tuning a design and assembly process to fabricate a rechargeable battery measuring as small as just two millimeters.

The findings, published in the Journal of Power Sources, offer a favorable outlook for various rugged applications including but not limited to medical devices, renewable energy, and the oil and gas industry.

"The achievable power and energy densities in microbatteries are significantly diminished due to size and mass domination from their internal hardware and packaging material," said Arava, principal investigator of the project. "We have minimized several traditional packaging components through design optimization in order to enhance the overall cell level capacity."

2mm-batteryThe technology is ideal for scenarios that require untethered, independent power sources that are not limited by conventional temperature restrictions and spatial limitations, such as extraterrestrial exploration, agile medical surgical procedures and directional drilling.

"Lithium-ion batteries are promising for high-temperature autonomous applications," said Nirul Masurkar, a graduate student in Arava's lab. "However, selection and design of electrode/electrolyte materials and packing them in miniatured battery format was challenging."

The team used additive manufacturing (i.e. 3D printing) techniques to construct battery casings and a solar cell unit to charge the battery. Challenges included optimizing battery chemistry and encapsulating the batteries without leaving behind an oversized footprint. The team came up with innovative solutions at each step while ensuring that the gains made in previous steps weren't lost or invalidated.

"In the present scenario, this miniaturized battery is better than any commercially-available batteries in terms of rechargeability, size, and power with a wide temperature working window," said Babu Ganguli, Ph.D., a former postdoc in Arava's group.

Untethered yet rechargeable compact power sources render crucial support to many autonomous systems without hindering their prime functionality. Arava says that they are preparing to take steps toward increased production of this technology for commercialization.

This research was supported by the Advanced Energy Consortium (AEC) member companies, including BHP, ExxonMobil, U.S. Department of Energy, Repsol, Sandia National Labs and Total.

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