Solar Cell Via Hole Electrode Design
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Solution Overview
Problem
Conventional solar cells experience reduced efficiency due to current collectors blocking light, which is mitigated by innovative designs such as metal wrap through and back contact solar cells, but these solutions do not fully address the issue of light absorption and charge transfer efficiency.
Innovation Solution
A solar cell design featuring a substrate with via holes of specific radii (10 μm to 40 μm) and electrodes that extend through these holes, allowing for efficient charge collection and reduced serial resistances, thereby enhancing light absorption and fill factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current collectors are formed on both the front and rear surfaces of the substrate, then charge collection is improved, but light absorption area is reduced
Solution Approach 1:
The current collector is extended vertically through the substrate via via holes, transitioning from a two-dimensional surface structure to a three-dimensional structure that passes through the substrate thickness direction, allowing charge collection without occupying front surface light absorption area
Solution Approach 2:
The current collector is divided into multiple segments: a first current collector on the rear surface, a second current collector extending through via holes to the front surface, and a third current collector on the front surface, with each segment positioned in different spatial locations to perform charge collection functions without mutual interference with light absorption
2Reliability
If via holes are made larger to improve charge transfer, then charge transfer efficiency is improved, but structural integrity and light absorption are reduced
Solution Approach 1:
The via hole radius is optimized to a specific range (10-40 μm) that balances charge transfer efficiency with substrate structural integrity, representing a precise parameter optimization to resolve the contradiction between these two requirements
Solution Approach 2:
The substrate is designed with localized via holes at specific positions rather than uniform distribution, allowing charge transfer at critical locations while preserving overall substrate strength and light absorption areas in non-via-hole regions
3Reliability
If electrodes are extended through via holes to improve electrical connection, then serial resistance is reduced, but manufacturing complexity increases
Solution Approach 1:
The electrode and current collector are merged into a continuous structure that extends from the front surface through the via holes to the rear surface, eliminating the need for separate welding or bonding processes and simplifying manufacturing while maintaining low serial resistance
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 proposed design improves solar cell efficiency by optimizing charge transfer and reducing serial resistances, leading to increased light absorption and power output without obstructing incident light.
Implementation Method 1
When light is incident on the solar cell, a plurality of electron-hole pairs are generated in the semiconductor. Each of the electron-hole pairs is separated into electrons and holes by the photovoltaic effect.
Data Source
AI summary
A solar cell includes a substrate of a first conductive type having at least one via hole; an emitter layer of a second conductive type opposite to the first conductive type; and at least one first electrode positioned from a first surface of the substrate to the at least one via hole, and at least one first electrode current collector positioned from the at least one via hole to a second surface of the substrate, wherein the at least one via hole has a radius of about 10 μm to about 40 μm, and at least one of a portion of the at least one first electrode and a portion of the at least one electrode current collector, in the at least one via hole, includes at least one cavity.