Photovoltaic Cells as Bypass Diodes via IBC Interconnection
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Solution Overview
Problem
Conventional solar power systems suffer from significant power output reduction and potential damage due to shading, as all cells in a series connection are affected by low light levels, leading to reverse breakdown and increased assembly and cost burdens from traditional bypass diodes.
Innovation Solution
Incorporating microsystem enabled photovoltaic cells as bypass diodes within photovoltaic sub-modules, where a subset of cells acts as diodes to provide a current path and protect against reverse bias voltages, reducing power loss and assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bypass diodes are added to protect photovoltaic cells from reverse breakdown, then cell reliability is improved, but assembly time and manufacturing cost increase
Solution Approach 1:
The patent merges the bypass diode function with existing photovoltaic cells by reconfiguring the cell interconnection pattern. Instead of adding separate diode components, the system uses the photovoltaic cells themselves in reverse bias mode as bypass diodes, eliminating the need for additional components and reducing assembly steps while maintaining protection against reverse breakdown
Solution Approach 2:
The photovoltaic cells serve dual functions: generating power during normal operation and acting as bypass diodes during shading conditions. This multi-functionality is achieved through the interdigitated back contact (IBC) configuration that enables reverse bias operation, allowing the same cells to perform both energy generation and protective functions
2Reliability
If traditional bypass diodes are added to protect photovoltaic cells, then cell reliability is improved, but manufacturing cost increases
Solution Approach 1:
The protective bypass diode function is merged into the existing photovoltaic cell structure through the IBC interconnection pattern, eliminating the need to purchase and install separate diode components. This reduces bill of materials costs and simplifies the manufacturing process
Solution Approach 2:
The photovoltaic cells provide their own protection function through the IBC configuration, eliminating the need for external protective components. The cells self-regulate by allowing reverse bias current flow through the interdigitated contacts, preventing damage without requiring additional protective devices
3Productivity
If photovoltaic cells are connected in series to achieve high voltage output, then system efficiency is improved, but the system becomes vulnerable to shading-induced reverse breakdown
Solution Approach 1:
The IBC interconnection creates a dynamic current path that automatically adapts to shading conditions. When one cell is shaded, the interdigitated back contact configuration dynamically redirects current flow through reverse-biased cells, preventing the static reverse breakdown that occurs in conventional series connections
Solution Approach 2:
The interdigitated back contact structure acts as an intermediary that mediates current flow between series-connected cells. This intermediate connection structure enables controlled reverse bias operation, allowing current to bypass shaded cells without causing damage to the series connection
4Ease of manufacture
If conventional solar panels use large silicon photovoltaic cells, then manufacturing is simplified, but shading affects a larger portion of the panel and causes greater power loss
Solution Approach 1:
The panel is segmented into multiple small photovoltaic cells rather than using fewer large cells. This segmentation reduces the impact area of shading events, so that when one cell is shaded, fewer total cells are affected. The IBC configuration further segments the current paths, isolating the effect of shading to individual cells or small groups
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 solution enhances the reliability and efficiency of solar power systems by minimizing power loss from shading and reducing manufacturing costs by eliminating the need for additional diodes, while maintaining optimal voltage levels for commercial inverters.
Implementation Method 1
Since the current of a photovoltaic cell is proportional to the light that is incident on the cell
Data Source
AI summary
A photovoltaic power generation system that includes a solar panel is described herein. The solar panel includes a photovoltaic sub-module, which includes a group of microsystem enabled photovoltaic cells. The group includes a first string of photovoltaic cells, a second string of photovoltaic cells, and a differing photovoltaic cell. Photovoltaic cells in the first string are electrically connected in series, and photovoltaic cells in the second string are electrically connected in series. Further, the first string of photovoltaic cells, the second string of photovoltaic cells, and the differing photovoltaic cell are electrically connected in parallel. Moreover, the differing photovoltaic cell is used as a bypass diode for the first string of photovoltaic cells and the second string of photovoltaic cells.