As the world develops more and more robots, powering them appropriately has become a major event. Moreover, as these robots become smaller and smaller, being able to fit regular stand-alone batteries in them is becoming an issue.
Scientists at the University of Michigan's Kotov Lab have developed a battery system for robots that operates much like us humans and animals store fat for energy, and it provides much more energy for the robots.
Their findings were published in Science Robotics on Wednesday.
72 times more energy provided
The scientists' new system provides 72 times more energy to robots than regular lithium-ion batteries. It is integrated into the body of the robot, which is what makes it resemble the fat energy storing system humans and animals use.
"Robot designs are restricted by the need for batteries that often occupy 20% or more of the available space inside a robot, or account for a similar proportion of the robot’s weight," said Nicholas Kotov, lead researcher of the study.
The team had to find a way to improve energy in non-lithium ion batteries, as these have been the structurally most powerful energy providers to date. As Kotov explained "No other structural battery reported is comparable, in terms of energy density, to today’s state-of-the-art advanced lithium batteries. We improved our prior version of structural zinc batteries on 10 different measures, some of which are 100 times better, to make it happen."
So the team looked into zinc batteries.
"We estimate that robots could have 72 times more power capacity if their exteriors were replaced with zinc batteries, compared to having a single lithium ion battery," said Mingqiang Wang, first author and visiting researcher to Kotov’s lab.
Aside from providing more energy, the zinc batteries are more environmentally friendly as they are made mostly with non-toxic materials. They also can't catch fire, unlike lithium-ion ones if they're damaged.
The team's battery functions by passing hydroxide ions between a zinc electrode and the airside via an electrolyte membrane.
The team trialed its design robots, which you can see in the video below.
The main negative aspect that remains to be seen is that zinc batteries are only able to maintain a high capacity for around 100 cycles, compared with over 500 for lithium-ion batteries.