Betavoltaic Power Source for Miniaturized Medical Implants
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Solution Overview
Problem
Current battery technologies face limitations in miniaturization, particularly for medical implants, due to low energy density and power output, which restricts the size reduction of medical devices and requires long-term power sources independent of visible light, especially for implants inaccessible to light sources.
Innovation Solution
Development of miniature betavoltaic power sources with enhanced energy densities, utilizing radioisotopes like Pm-147 and tritium, integrated with semiconductor collectors and radiation shielding, allowing for efficient power generation in small volumes and the ability to trickle-charge secondary batteries for sustained operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional chemical batteries are used in medical implants, then the device can operate for extended periods, but the battery volume occupies 40-80% of the total device volume, preventing further miniaturization
Solution Approach 1:
The patent transitions from conventional chemical battery energy storage to betavoltaic energy conversion, fundamentally changing the energy supply parameter from finite chemical energy to continuous radioactive decay energy, enabling long-term operation without proportional volume increase
Solution Approach 2:
The patent employs a hybrid system combining betavoltaic cells with selective radiation shielding materials, creating a composite structure that generates power while protecting sensitive electronics, achieving both longevity and miniaturization
2Volume of moving object
If battery size is reduced to enable miniaturization of medical devices, then device volume decreases, but energy density and capacity are exponentially reduced
Solution Approach 1:
The betavoltaic system is self-sustaining, using the natural radioactive decay of the isotope to continuously generate electrical energy without requiring external recharging or replacement, effectively providing infinite energy capacity for the device's operational lifetime
Solution Approach 2:
The patent moves from two-dimensional surface-area-limited solar cells to three-dimensional volume-efficient betavoltaic cells, where the radioactive isotope can be distributed throughout the volume of the cell, dramatically increasing energy density
3Duration of action of stationary object
If solar cells are used to trickle-charge batteries in implants, then the battery can be recharged indefinitely, but the solution is ineffective for implants inaccessible to visible light sources
Solution Approach 1:
The betavoltaic system provides universal power generation capability that functions independently of environmental conditions such as light availability, making it adaptable to all implant locations including those inaccessible to visible light
Solution Approach 2:
The patent replaces the optical-based solar cell system with a nuclear-based betavoltaic system, substituting the mechanism of light-to-electricity conversion with radioactive decay-to-electricity conversion, eliminating the light accessibility constraint
4Quantity of substance
If radioisotopes are used in betavoltaic cells, then high energy density is achieved, but radiation shielding requirements increase device complexity
Solution Approach 1:
The patent applies radiation shielding selectively only to the regions containing sensitive electronics and the betavoltaic cell, rather than enclosing the entire device, optimizing the balance between radiation protection and device miniaturization
Solution Approach 2:
The patent introduces a thin layer of shielding material as an intermediary between the radioactive isotope and the surrounding environment, effectively blocking harmful radiation while minimizing the impact on device volume and allowing the high energy density benefit to be realized
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 betavoltaic power sources achieve energy densities of up to 500 watt-hours per cubic centimeter and power densities of 10's to 100's of microwatts per cubic centimeter, enabling long-term operation of medical implants with reduced shielding requirements and the ability to modulate power for various medical device functions.
Implementation Method 1
miniature betavoltaic power sources
Implementation Method 2
semiconductor collectors
Implementation Method 3
radioisotopes like Pm-147 and tritium
Data Source
AI summary
A betavoltaic power source. The power source comprises a source of beta particles, one or more regions for collecting the beta particles and for generating electron hole pairs responsive thereto, and a secondary power source charged by a current developed by the electron hole pairs.