Micro-PV Cell Arrays With Monolithic Bypass Diodes for Shadow Tolerance
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Solution Overview
Problem
Existing PV solar panels face challenges in fully utilizing the available area due to the need for multiple circuits of solar cells, which often results in reduced power output as not all cells can be utilized effectively, especially in space applications where high photocurrents and Electro Static Discharge (ESD) are concerns.
Innovation Solution
The integration of monolithic bypass diodes with multi-junction micro-PV cells, where each cell has its own integrated bypass diode, allows for series connection without the need for shadowed cells to reverse bias, thereby protecting the circuit and maximizing power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple circuits of solar cells are used to fill panel area, then panel area utilization improves, but power output decreases due to inability to fully utilize all cells
Solution Approach 1:
The patent merges the bypass diode function into the solar cell structure itself by creating an integrated monolithic bypass diode within each individual solar cell. This integration allows the bypass diode to be formed simultaneously with the solar cell in a single monolithic structure, eliminating the need for separate bypass diode components and enabling more efficient use of panel area while maintaining high power output through proper cell utilization.
2Reliability
If shadowed cells are allowed to reverse bias, then circuit protection is needed, but this complicates the circuit design and reduces reliability
Solution Approach 1:
The integrated monolithic bypass diode provides preliminary protection by being pre-integrated into each solar cell structure. When a cell becomes shadowed, the bypass diode automatically activates to prevent reverse bias damage before it can affect the entire circuit, eliminating the need for complex external protection circuits and simplifying the overall design while maintaining high reliability.
3Quantity of substance
If large PV solar cells are used, then fewer cells are needed per panel, but challenges arise with high photocurrents and Electro Static Discharge (ESD)
Solution Approach 1:
The patent segments the panel into multiple smaller solar cells rather than using fewer large cells. Each small solar cell is equipped with its own integrated monolithic bypass diode, which protects against high photocurrents and ESD events. This segmentation approach distributes the electrical stress across multiple protected units, reducing the harmful effects on any single cell while maximizing panel area utilization.
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
This configuration enables efficient use of the panel area by preventing damage from reverse biasing, maintaining circuit photocurrent, and ensuring high power output even under shadowed conditions, thus optimizing power generation in space applications.
Implementation Method 1
multi-junction, photovoltaic (PV) micro-PV cell arrays with integrated monolithic bypass diodes used for PV solar panels
Implementation Method 2
an integrated monolithic bypass diode comprising the second layer disposed on the first layer
Data Source
AI summary
A photovoltaic (PV) solar panel, made of many micro-PV cells, where each micro-PV cell has its own integrated, monolithic bypass diode. Each micro-PV cell is a multi-junction solar cell that is approximately 1 cm on a side. An array of approximately fifty micro-PV cells, all connected in series, makes up a single “PV device”, which generates 90-100 V at a low current. A PV solar panel includes multiple strings of these PV devices, connected in parallel, which generates a high photocurrent at 90-100 V. The multi-junction micro-PV cells can be made of stacked layers of Ge, GaAs, and InGaP PN.