King Cobra snake

Battery bends and stretches like a snake

Image credit: Dreamstime

Korean researchers have developed a safe, flexible and stretchable battery capable of smooth movement which mimics the motion of snake scales. The device could have a range of applications in soft robotics and wearable devices.

A snake’s individual scales, while rigid, can fold together to protect against external impacts. They possess structural characteristics that allow them to stretch and move flexibly. It is this unique set of properties that researchers from the Ministry of Science and ICT’s Korea Institute of Machinery and Materials decided to replicate in a mechanical meta structure.

Unlike conventional wearable devices, in which the device’s frame and battery are combined in a tight formation, this new device enables flexible movement by connecting several small, rigid batteries in a scale-like structure. To ensure its safety, the researchers optimised the structure to minimise deformation of the material from which the battery was made. The shape of each battery cell is optimised to achieve high capacity per unit size.

Key to the unique device are the shapes of the battery cell and connective components. Small, hexagonal cells, resembling snake scales, were connected with polymer and copper, which uses a hinge mechanism to fold and unfold.

The researchers hope that this design could facilitate mass production in future, as the battery can be made by cutting and folding flexible electrodes with a manufacturing process inspired by origami.

The device could be implemented in energy-storage devices found in wearable devices for humans that require soft and flexible energy storage devices, or for those found in rehabilitation medical devices for the elderly and the sick who need physical assistance. In addition, these batteries are expected to be useful as power supply devices for soft robots that are used on site during disasters to help conduct rescue missions. Thanks to their ability to move flexibly and freely change shape, robots equipped with these batteries can be used to access narrow spaces blocked off by obstacles during such disaster situations.

Dr Bongkyun Jang, the senior researcher who co-led the research at the institute’s Department of Nanomechanics, commented that mimicking snake scales helped them developed a battery that was flexible, stretchable, and safe to use. In future, he hopes to continue developing soft energy storage devices, including boosting their storage capacity and developing multi-functional soft robots that combine artificial muscles with soft robot actuation technology.

A report describing the development of the battery, 'Bioinspired, Shape-Morphing Scale Battery for Untethered Soft Robots', has been published in the journal Soft Robotics.

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