Flexible Lithium-Ion Battery Inspired by the Human Spine

Innovation: Academia

Columbia University

2018

Image: Inge Poelman / Unsplash / Free non-commercial use

Store Energy

Once a living system captures energy or transforms one energy form into another, it must frequently save that energy for future use. But energy is difficult to store in some forms. So living systems need strategies to either use energy quickly, or to convert it from forms that are difficult to store (such as electrical or kinetic) to more storable forms. For example, grasshoppers store energy as potential energy in an elastic material in their tendons. When they need to jump, that energy converts into kinetic energy, providing the force needed to escape predators.

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Modify Size/Shape/Mass/Volume

Many living systems alter their physical properties, such as size, shape, mass, or volume. These modifications occur in response to the living system’s needs and/or changing environmental conditions. For example, they may do this to move more efficiently, escape predators, recover from damage, or for many other reasons. These modifications require appropriate response rates and levels. Modifying any of these properties requires materials to enable such changes, cues to make the changes, and mechanisms to control them. An example is the porcupine fish, which protects itself from predators by taking sips of water or air to inflate its body and to erect spines embedded in its skin.

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Lithium-ion battery from Columbia University has rigid segments with flexible interconnections that give the battery good flexibility and high energy density.

Benefits

Stable
Scalable
Flexible

Applications

Soft Robotics
Electronics

UN Sustainable Development Goals Addressed

Goal 9: Industry Innovation & Infrastructure
Goal 12: Responsible Production & Consumption

The Challenge

Wearable and portable electronics require small, stable batteries to function properly. To achieve longer-lasting charges on devices, batteries must be larger, which also makes them heavier. Developing high performance, high energy density, and flexible batteries would improve small, portable electronics.

Innovation Details

The lithium-ion batteries are made of an energy-storing rigid segment, which coils around the flexible part that connects the vertebra-like stacks of electrodes. The volume of the electrodes, which is the active material in the structure, is larger than the volume of the flexible interconnection, creating a battery with a high energy density. Due to the resilience in the connections between the components within the structure, the batteries have a stable voltage no matter how they are flexed or twisted.

Biomimicry Story

Human spines are highly flexible and can distort while remaining mechanically robust. Spinal disks have a solid, multi-layered casing of cartilage fiber and a gel-like core. This structure helps keep the spine flexible for rotational movement and bending forwards and backwards.

References

Journal article

Bioinspired, Spine-Like, Flexible, Rechargeable Lithium-Ion Batteries with High Energy Density

Advanced Materials

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