Back-Contact Solar Cell Stringing Without Busbars
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Solution Overview
Problem
Existing solar cell manufacturing techniques face inefficiencies due to the use of busbars and metal fingers, which reduce overall efficiency and increase costs, and the process of forming these features poses manufacturing difficulties.
Innovation Solution
A novel metallization and stringing method for back-contact solar cells using continuous conductive wires to directly connect P-type and N-type doped diffusion regions, followed by selective cutting to restore separate electrodes, eliminating the need for busbars and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If busbars and metal fingers are used to connect doped regions, then electrical connection is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the busbar and metal finger structures from the solar cell design. Instead of using these traditional conductive elements to connect doped regions, the invention directly connects alternating P-type and N-type doped diffusion regions through the semiconductor substrate, removing the unnecessary intermediate conductive components and simplifying the overall device structure.
Solution Approach 2:
The patent inverts the traditional approach by placing all conductive elements (both P-type and N-type contacts) on the back surface of the solar cell rather than on the front surface. This back-contact configuration eliminates the need for front-side metal fingers that interfere with light absorption and simplifies the front surface structure, allowing full utilization of the light-receiving area.
2Power
If busbars and metal fingers are formed on solar cells, then current collection is enabled, but overall efficiency decreases
Solution Approach 1:
The patent transitions from a planar configuration where metal fingers extend across the front surface to a three-dimensional back-contact configuration. By moving all electrical contacts to the back surface and using vertical conductive pathways through the substrate, the invention eliminates the trade-off between current collection and light absorption area, as the front surface remains completely free of obstructive metal structures.
3Reliability
If traditional metallization processes are used, then conductive regions are formed, but manufacturing cost increases
Solution Approach 1:
The patent merges the formation of P-type and N-type conductive regions into a single integrated process step. By simultaneously creating alternating doped diffusion regions that extend to the back surface and forming all back-contact metallization in one processing cycle, the invention eliminates multiple separate metallization steps, reducing manufacturing complexity and cost while maintaining reliable electrical connections.
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 approach enhances solar cell efficiency and reduces manufacturing complexity by directly connecting diffusion regions with conductive wires, thereby improving power generation capabilities and lowering production costs.
Implementation Method 1
A plurality of conductive wires is disposed over a back surface of each of the plurality of solar cells, wherein each of the plurality of wires is substantially parallel to the P-type and N-type doped diffusion regions of each of the plurality of solar cells
Data Source
AI summary
Metallization and stringing methods for back-contact solar cells, and resulting solar cells, are described. In an example, in one embodiment, a method involves aligning conductive wires over the back sides of adjacent solar cells, wherein the wires are aligned substantially parallel to P-type and N-type doped diffusion regions of the solar cells. The method involves bonding the wires to the back side of each of the solar cells over the P-type and N-type doped diffusion regions. The method further includes cutting every other one of the wires between each adjacent pair of the solar cells.