Researchers led by The University of Texas at Austin have uncovered why batteries in wireless earbuds don’t last as long as they once did. Using advanced imaging technologies, they identified the factors causing battery degradation over time.
Have you ever noticed your wireless earbuds battery life dwindling far quicker than when you first bought them? A new study conducted by an international research team led by Yijin Liu of The University of Texas at Austin, and published in Advanced Materials, has shed light on this common issue. The researchers utilized advanced imaging technologies, such as x-ray and infrared, to unravel why batteries in compact devices like wireless earbuds degrade over time.
“This started with my personal headphones; I only wear the right one, and I found that after two years, the left earbud had a much longer battery life,” Liu, an associate professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering, said in a news release. “So, we decided to look into it and see what we could find.”
Through their investigation, the team discovered that multiple components within these tiny gadgets, including Bluetooth antennas, microphones and circuits, create a challenging microenvironment that affects the battery’s lifespan.
One of the key findings was the temperature gradient — different temperatures at the top and bottom portions of the battery — which contributes to its degradation.
Moreover, exposure to real-world conditions, such as varying temperatures and differing air qualities, also play a significant role. Although batteries are designed to endure harsh environments, the frequent changes present unique challenges, the researchers noted.
“Using devices differently changes how the battery behaves and performs,” added first author Guannan Qian, a postdoctoral researcher in Liu’s lab. “They could be exposed to different temperatures. One person has different charging habits than another. And every electric vehicle owner has their own driving style. This all matters.”
For this extensive study, Liu’s team collaborated closely with the UT Fire Research Group, led by mechanical engineer Ofodike Ezekoye, employing infrared imaging technology to supplement their x-ray analyses.
To deepen their understanding, they sought assistance from world-class synchrotron facilities. Collaborators included teams from SLAC National Accelerator Laboratory’s Stanford Synchrotron Radiation Lightsource, Brookhaven National Laboratory’s National Synchrotron Light Source II, Argonne National Laboratory’s Advanced Photon Source and the European Synchrotron Radiation Facility (ESRF) in France.
“Most of the time, in the lab, we’re looking at either pristine and stable conditions or extremes,” Xiaojing Huang, a physicist at Brookhaven National Laboratory, said in the news release. “As we discover and develop new types of batteries, we must understand the differences between lab conditions and the unpredictability of the real world and react accordingly. X-ray imaging can offer valuable insights for this.”
This research illuminates the complexities of battery degradation in real-world devices and underscores the necessity of considering user behaviors, environmental factors and device interactions in the design of future battery technologies. Liu’s team intends to continue exploring battery performance under real-world conditions, extending their efforts to larger batteries powering phones, laptops and electric vehicles.