Polymeric Piezoelectric Harvester for Self-Charging Implants
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Solution Overview
Problem
Implantable devices such as pacemakers and deep-brain neurostimulators require frequent battery replacements due to the limitations of existing power sources, including transdermal charging and solar panels, which are inefficient or impractical for frequent movement scenarios.
Innovation Solution
A piezoelectric energy harvester with a layered structure comprising a polymeric piezoelectric material, such as PVDF, coupled with electrodes to convert mechanical stress into electrical energy, charging a capacitor or battery through bistable mechanical structures that efficiently generate power from environmental movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If transdermal electromagnetic induction coil chargers are used to power implantable devices, then electrical energy can be transmitted through the skin, but the system requires maintenance of external charging devices and regular user intervention
Solution Approach 1:
The piezoelectric energy harvester automatically converts mechanical stress from body movements, muscle contractions, or external pressure into electrical energy to charge the implantable device battery. This self-charging mechanism eliminates the need for external charging devices and user intervention, as the device harvests energy autonomously from its operational environment.
2Use of energy by moving object
If solar panels are used to harvest energy for implantable devices, then environmental light energy can be converted to electrical power, but skin absorption of light significantly reduces efficiency
Solution Approach 1:
The patent replaces the optical energy conversion system (solar panels) with a mechanical energy conversion system (piezoelectric materials). Instead of converting light energy that is blocked by skin, the piezoelectric harvester converts mechanical stress from body movements, muscle contractions, or external pressure directly into electrical energy, bypassing the skin's light absorption problem entirely.
3Use of energy by moving object
If mechanical self-winding weights are used to harvest energy from movement, then kinetic energy can be converted to electrical power, but the device structure becomes complex and bulky
Solution Approach 1:
The patent changes the physical state and properties of the piezoelectric material to achieve efficient energy harvesting. By using polymeric piezoelectric materials with specific piezoelectric coefficients and mechanical properties, the system achieves effective energy conversion from mechanical stress without requiring complex mechanical structures like self-winding weights. The material's inherent piezoelectric properties enable direct conversion of applied stress into electrical energy.
Solution Approach 2:
The energy harvester employs a composite structure combining piezoelectric material layers with electrode layers and flexible substrate materials. This composite design integrates multiple functions (energy conversion, electrical conduction, flexibility) into a single thin-film structure, eliminating the need for bulky mechanical components while maintaining effective energy harvesting capability.
4Reliability
If implantable devices use traditional batteries, then reliable power supply is achieved, but frequent battery replacement requires surgery
Solution Approach 1:
The piezoelectric energy harvester continuously charges the implantable device battery during normal operation by harvesting energy from body movements and muscle contractions. This continuous energy replenishment extends the effective operational life of the battery far beyond its natural discharge cycle, eliminating or significantly reducing the frequency of battery replacement surgeries while maintaining reliable power supply.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The piezoelectric energy harvester effectively harnesses mechanical stress to generate significant electrical power, providing a sustainable and efficient means to recharge implantable devices and power small electronic devices, even in situations where traditional power sources are inconvenient or unreliable.
Implementation Method 1
Piezoelectric materials are materials that, when subjected to mechanical stress, generate electricity
Data Source
AI summary
A piezoelectric energy harvester has a layered structure comprising a first electrode, a polymeric piezoelectric material, and a second electrode, the layered structure coupled to receive mechanical stress from the environment, and the first and second electrode electrically coupled to a power converter. The power converter is adapted to charge an energy storage device selected from a capacitor and a battery. The method of harvesting energy from the environment includes providing a piezoelectric device comprising a layer of a polymeric piezoelectric material disposed between a first and a second electrode; coupling mechanical stress derived from an environment to the piezoelectric device; and coupling electrical energy from the piezoelectric device.