Kudzu is a vine from Asia. It is spreading across the United States faster than herbicides can keep up. It is also an analogy. In 2013, Berkley Lab thought that lithium-ion batteries could short-circuit when cycled too quickly. They used a non-destructive viewing method called ‘hard x-rays’.
The microscopic fibers spreading from the lithium electrode across the electrolyte reminded them of the alien plant. They believed a battery could overheat and catch fire once the ‘kudzu’ reached the other electrode. Later, they called the tendrils dendrites, after the branched connections of neurons.
Lithium Kudzu in Real Life
Prof Alexej Jerschow of New York University decided to take the dendrite theory further last month. He used three-dimensional magnetic resonance imaging to peer inside a lithium-ion battery. He saw what could almost be a liquid android from Judgment Day but of course it was not.
He imagined he was looking at Berkley Lab dendrites developing before his eyes. In reality, he was observing the distortion of the electrolytes as the dendrites shoved them aside.
“The method examines the space and materials around dendrites, rather than the dendrites themselves,” study author Andrew Ilott explains. “As a result, the method is more universal. Moreover, we can examine structures formed by other metals, such as for example sodium or magnesium. Materials that are currently possible alternatives to lithium.”
What This May Mean for Batteries
We appear to be a little closer to understanding what happened to a few Galaxy Note 7 phones. If the Berkley Lab was correct back in December 2013 the root cause may turn out to be rogue-cycling rates.
Live Science thinks there may be potential to trigger alarms inside batteries before the situation reaches danger point. We shall watch this kudzu story with interest.