Battery safety and performance in electronic devices and systems such as battery power management, space management, vehicle lighting comfort and energy conservation can be improved using adaptive power management developed at the Purdue University College of Engineering.
Xiulin Ruan and Amy Marconnet have invented a patent-pending, solid-state, flexible thermal device based on graphene foam composites. Devices can spread heat, cover cold, and operate across extreme temperatures. Ruan is a professor in the School of Mechanical Engineering. Marconnet is an Associate Professor in the School of Mechanical Engineering and a Perry Academic Excellence Fellow; He also has a tenure at the School of Materials Engineering.
“As batteries and electronic devices become more powerful, temperature control becomes more important,” Ruan said. “We all know that humans have a narrow temperature range to live in comfort, so we wear shirts in summer to stay cool and clothes in winter to keep warm. Similarly , batteries and electronic devices have a narrow temperature range to work efficiently, and even more “fingers” than humans.
“Batteries work best when they are very hot,” says Marconnet. As they heat up, chemical reactions cause them to heat up even faster. This unstable progress of the reaction is called “running hot” and can even lead to fire and explosion. On the other hand, if the temperature is too low, the battery suffers internal damage. This leads to poor performance, such as shortfalls for electric vehicles and short periods of mobile phone use.
Traditional electronic switches, such as electrical switches that allow current to flow through, regulate the discharge of the battery simply by changing the direction between the on and off states. Ruan said the Purdue-designed thermocouples improve this technology by changing the size of the material inside the regulator, which helps the battery keep up with changes in the climate differences in time.
“Unlike people who can wear a suit when it’s cold or a bathing suit when it’s hot, batteries wear the same ‘clothing’ everywhere with temperature control technology,” Marconnet said. . “By using a heat exchanger to repair the path between the battery and the environment, we can insulate the battery in cold conditions and help heat it in hot conditions.”
The commercially scalable graphene foam used by Ruan and Marconnet is made from nanoscopic carbon particles arranged in a specific shape with small air spaces in between. When not attached, the foam acts as an insulator; Air pockets hold heat in place. When it is compressed, the air escapes and the heat is conducted everywhere. The rate of heat transfer can be very good depending on the degree of foam compression.
Marconnet and Ruan studied the thermal properties of foams at Purdue’s Birck Nanotechnology Center. They collected a sample of graphene foam 1.2 millimeters wide between the heatsink and the hot spot, and put the system under an infrared microscope to measure the temperature and temperature. When they fully integrated the foam with a thickness of 0.2 millimeters, the thermal conductance increased 8 times. They also conducted experiments in a room in Purdue’s Flex Lab that can create specific environmental conditions and get similar results. and temperatures range from zero degrees Celsius (32 degrees Fahrenheit) to 30 degrees Celsius (86 degrees Fahrenheit).
Ruan said the patents pending are designed for electric vehicle batteries, but there are other applications.
“The same process can be applied to sensors and detectors for scientific or industrial applications that need to be kept at temperature, as well as electronic devices in many applications,” Ruan said. “It can also help maintain the right temperature for space vehicles, which face harsh environments of extreme heat and cold.”
Ruan and Marconnet’s research has been published in two peer-reviewed journals. The battery pack review was published in August. 13, 2021, issue of Nature Communications; The main research was published in the October 18, 2022 issue of ACS Applied Materials & Interfaces.
Ruan and Marconnet exposed the heat to the Purdue Research Foundation’s Technology Commercialization Office, which filed for intellectual property rights protection. Industry partners interested in further developing the technology for commercialization should contact Dhananjay Sewak, dsewak@prf.org, around 2020 RUAN-68896, “A Thermal Switch and Regulator Device Based on Graphene Foams”.
Marconnet and Ruan outlined other methods to develop Purdue’s heating engineers.
“We want to improve the results of the thermal conductances that are achieved in the organizer. The best heaters have an efficiency ratio of only 10. Unlike electric motors, resistors can change by orders of magnitude. If we can improve the behavior of light and make it better, we can make the controller work better, ” Marconnet said.
“In addition, in the laboratory, temperature control is performed manually. We will work to automate this process, can take into account the feedback from the temperature sensor to adjust the settings automatically.
Source: Purdue University
