Back-Contact Solar Cell Finger Layout for Lower Internal Loss
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Solution Overview
Problem
The long current transmission distance and large internal loss in back contact solar cells affect the photoelectric conversion efficiency due to the arrangement of electrode busbars and fingers, leading to increased resistance and reduced efficiency.
Innovation Solution
The solar cell design includes first and second connection segments where the first connection segments burn through the passivation layer to connect with the doped region, while the second connection segments do not, allowing for direct current collection and reducing transmission distance and internal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrode busbars and fingers are arranged on the back surface to avoid blocking the front surface, then the photoelectric conversion efficiency is improved, but the current transmission distance increases and internal loss increases
Solution Approach 1:
The electrode pattern is segmented into first fingers extending in a first direction and second fingers extending in a second direction intersecting with the first direction. This segmentation creates multiple current collection paths, reducing the current transmission distance and internal loss while maintaining the back contact configuration that avoids blocking the front surface.
Solution Approach 2:
The patent introduces a two-dimensional grid of fingers by adding second fingers in a direction intersecting with the first direction. This dimensional expansion transforms the single-direction current collection into multi-directional collection, effectively reducing the transmission distance and internal loss without compromising the photoelectric conversion efficiency.
2Productivity
If electrode busbars and fingers are arranged on the back surface to avoid blocking the front surface, then the photoelectric conversion efficiency is improved, but the resistance increases
Solution Approach 1:
The electrode system is divided into multiple first fingers and second fingers arranged in intersecting directions. This segmentation creates numerous parallel current paths, reducing the overall resistance by distributing the current flow across multiple shorter pathways instead of relying on long single paths.
Solution Approach 2:
By adding the second dimension of fingers intersecting with the first direction, the patent creates a two-dimensional current collection network. This reduces resistance by providing multiple short pathways for current flow, eliminating the need for long transmission paths that would increase resistance.
3Ease of manufacture
If connection lines are used to connect positive electrode fingers to soldering points, then current collection is achieved, but the current transmission distance increases and internal loss increases
Solution Approach 1:
The first fingers and second fingers are merged to form an integrated grid structure that directly collects and transmits current. This merging eliminates the need for separate connection lines between fingers and soldering points, as the intersecting fingers themselves create direct current pathways, reducing transmission distance and internal loss.
Solution Approach 2:
The addition of second fingers in an intersecting direction creates a two-dimensional current collection network that eliminates the need for long connection lines. The grid structure provides direct current pathways through the finger intersections, replacing the traditional linear connection line approach and reducing internal loss.
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 design reduces current transmission distance and internal loss, thereby improving the photoelectric conversion efficiency of the solar cell by enhancing current collection and transmission.
Implementation Method 1
The first connection segments burn through the passivation layer and are electrically connected to the doped region
Implementation Method 2
a solar cell body, where the solar cell body includes a substrate, a doped region formed on the substrate
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present application discloses a solar cell and a photovoltaic module, and belongs to the field of photovoltaic technologies. The solar cell includes a first pattern region, the first pattern region includes a plurality of first fingers extending along a first direction and arranged at intervals along a second direction, each of the first fingers includes a plurality of first connection segments disposed at intervals along the first direction and second connection segments connected between two adjacent first connection segments, and the second direction intersects with the first direction. A plurality of second connection segments are arranged at intervals along the second direction, and at least one of the first connection segments is disposed between two adjacent second connection segments. The first connection segments burn through the passivation layer and are electrically connected to the doped region, and the second connection segments do not burn through the passivation layer.