Solar Cell With Integrated Recessed Bypass Diode
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Solution Overview
Problem
Existing solar cell structures face challenges in protecting against reverse-bias damage and efficient heat removal, particularly in configurations where by-pass diodes interfere with heat dissipation and can cause assembly issues or reduced efficiency.
Innovation Solution
Integrating a discrete by-pass diode into the solar cell structure at the back side, combined with a heat sink that promotes heat transfer, ensuring the diode does not obscure the front side and is connected via short leads, allowing for effective heat removal and protection against reverse-bias damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the discrete by-pass diode is bonded to the backside of the solar cell and interconnected with leads, then reverse-bias protection is provided, but the solar cell is exposed to stresses that may cause cracking if pressure is applied during assembly bonding
Solution Approach 1:
The by-pass diode is moved from a planar bonding configuration to a three-dimensional recessed structure. The diode is received in a recess formed in the backside of the solar cell, allowing it to be positioned below the surface level. This dimensional change eliminates the need for high-pressure bonding that causes cracking while maintaining electrical connection through leads that extend from the diode to the solar cell contacts.
2Strength
If the by-pass diode is placed into a recess on the back side of the solar cell, then assembly stresses are reduced, but this approach is operable only for relatively thick solar cells
Solution Approach 1:
The recess structure is designed to accommodate by-pass diodes for solar cells of varying thicknesses. The recess can be formed to different depths and configurations depending on the specific solar cell thickness, making the solution universally applicable. Additionally, the recess serves multiple functions: it provides mechanical support, reduces assembly stresses, and allows for proper lead routing regardless of the solar cell thickness.
3Ease of manufacture
If the by-pass diode is placed to one side of the solar cells, then assembly is simplified, but wiring must extend between the solar cell and the by-pass diodes
Solution Approach 1:
The by-pass diode is merged with the solar cell structure by placing it directly into a recess on the backside of the solar cell itself. This integration eliminates the need for separate wiring extensions between the solar cell and the diode. The leads from the diode connect directly to the solar cell contacts through the recess, creating a compact, self-contained unit that simplifies both assembly and reduces wiring complexity.
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 solution provides a compact solar cell structure with both reverse-bias protection and enhanced heat removal, improving performance and reliability by maintaining optimal operating temperatures without assembly complications.
Implementation Method 1
each solar cell may be protected against the damage arising during the reverse-bias condition by a parallel diode that blocks current when the solar cell is not reverse biased
Implementation Method 2
An intermediate structure is disposed between and joined to the back side of the solar cell and to the heat sink... promotes heat transfer from the solar cell to a heat sink
Data Source
AI summary
A solar cell structure has a solar cell unit structure including a heat sink, and a solar cell having a front side, a back side, and a solar-cell projected area coverage on the heat sink. The solar cell has an active semiconductor structure that produces a voltage between the front side and the back side when the front side is illuminated. An intermediate structure is disposed between and joined to the back side of the solar cell and to the heat sink. The intermediate structure has an intermediate-structure projected area coverage on the heat sink and includes a by-pass diode having a diode projected area coverage on the heat sink. The diode projected area coverage on the heat sink may be substantially the same as the intermediate-structure projected coverage on the heat sink. Alternatively, the diode projected area coverage on the heat sink maybe less than the solar-cell projected area coverage on the heat sink, and the intermediate structure further includes a substrate coplanar with the by-pass diode.