# Crumpling for Energy: Modeling Generated Power from the Crumpling of Polymer Piezoelectric Foils for Wearable Electronics

## TL;DR

This paper models how the crumpling of polymer piezoelectric foils in clothing can generate electrical power through human movement, providing theoretical insights and experimental validation for wearable energy harvesting.

## Contribution

It introduces a theoretical model and scaling laws for power generation from crumpled polymer piezoelectrics in clothing, highlighting stretching as the main charge mechanism.

## Key findings

- Power scales with crumple size and rate, with voltage and current depending on the crumple height.
- Stretching dominates charge generation over bending or compression.
- Experimental results confirm the theoretical scaling laws.

## Abstract

We consider possibility of embedding large sheets of polymer piezoelectrics in clothing for sensing and energy harvesting for wearable electronic applications. Power is generated by the crumpling of clothes due to human body movements. From the mechanics of a gently crumpled foil we develop theoretical models and scaling laws for the open circuit voltage and short circuit current and verify via experiments. It is concluded that stretching is the dominant charge generation mechanism with the open circuit voltage and short circuit current scaling as $l^{i}$ and $l^{i-1}(\mbox{d}l/\mbox{d}t)$, respectively with $1\leq i\leq 4/3$ and $l$ the height of the crumple cone.