A lithium-ion battery that self heats if the temperature is below 32 degrees Fahrenheit has multiple applications, but may have the most impact on relieving winter “range anxiety” for electric vehicle owners, according to a team of researchers from Penn State and EC Power, State College.
“It is a long standing problem that batteries do not perform well at subzero temperatures,” said Chao-Yang Wang, William E. Diefenderfer Chair of mechanical engineering, professor of chemical engineering and professor of materials science and engineering and director, Electrochemical Engine Center. “This may not be an issue for phones and laptops, but is a huge barrier for electric vehicles, drones, outdoor robots and space applications.”
Conventional batteries at below freezing temperatures suffer severe power loss, which leads to slow charging in cold weather, restricted regenerative breaking and reduction of vehicle cruise range by as much as 40 percent, the researchers said in today’s (Jan. 20) issue of Nature. These problems require larger and more expensive battery packs to compensate for the cold sapping of energy.
Tune In, Turn On, Power Up
Human beings don’t come with power sockets, but a growing numbers of us have medical implants that run off electricity. To keep our bionic body parts from powering down, a group of Arizona researchers is developing a safe, noninvasive, and efficient means of wireless power transmission through body tissue. The team presents their findings at the 166th meeting of the Acoustical Society of America, held Dec. 2 – 6 in San Francisco, Calif.
Medical implants treat a variety of conditions such as chronic pain, Parkinson’s disease, deep brain tremors, heart rhythm disturbances, and nerve and muscle disorders. If the batteries in the devices lose their charge, minor surgery is needed to replace them, causing discomfort, introducing the risk of infection, and increasing the cost of treatment.
This is a scenario the Arizona researchers are aiming to change.
Their novel wireless power approach is based on piezoelectric generation of ultrasound. The Greek root, “piezo”, means “squeeze.” In piezoelectrical systems, materials are squeezed or stressed to produce a voltage. In turn, applied voltages can cause compression or extension. Piezoelectric materials have specific crystalline structures. The team’s piezoelectric system has been tested in animal tissue with encouraging results.