Back-Contact Solar Cell Multi-Section Gate Lines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing busbar-free back-contact solar cell technologies face challenges in efficiently connecting IBC cells in series due to series resistance issues and high manufacturing costs, particularly for larger silicon wafers, and are prone to current leakage and misconnection problems.
Innovation Solution
A busbar-free and high-efficiency back-contact solar cell module with a multi-section structure of small conductive gate lines interdigitally arranged in parallel, connecting P-electrodes and N-electrodes on the backlight side, and using a decentralized connection system to reduce series resistance and stress on the cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional conductive backing composite plate with copper foil is used for MWT assembly, then electrical connection is achieved, but laser etching is slow for complex patterns and chemical corrosion causes environmental pollution and high cost
Solution Approach 1:
The patent extracts the conductive adhesive application process from the complex backing plate preparation process. Instead of etching copper foil and punching packaging material, the conductive adhesive is directly applied to the back contact electrodes through a simple dispensing process, eliminating the need for complex pattern etching and masking operations.
Solution Approach 2:
The patent introduces conductive adhesive as an intermediary material between the back contact electrodes and the external circuit. This adhesive mediator simplifies the connection process by directly bonding to the electrodes without requiring complex conductive backing plates, laser etching, or chemical corrosion processes.
2Reliability
If tin-plated copper band is used for series connection, then electrical connection is achieved, but thick bands may crack the cell due to excessive hardness while thin bands shield much sunlight
Solution Approach 1:
The patent extracts the series connection function from the front-side gate lines and relocates it to the back contact electrodes. By moving all electrical connections to the back side, the front surface is completely freed from conductive elements, eliminating the trade-off between connection reliability and optical loss entirely.
Solution Approach 2:
The patent inverts the conventional architecture by placing all electrodes and connections on the back side of the cell rather than the front side. This inversion allows the front surface to be fully optimized for light absorption while the back side handles all electrical functions, resolving the contradiction between mechanical strength and optical performance.
3Productivity
If front-side gate lines are used for carrier collection, then collection efficiency is improved, but light shielding by gate lines reduces effective light-receiving area
Solution Approach 1:
The patent inverts the electrode placement from front side to back side. By moving the gate lines and all conductive elements to the back surface, the front surface achieves 100% light reception area while the back side performs carrier collection, completely eliminating the light shielding problem.
Solution Approach 2:
The patent transitions the electrical connection function from the two-dimensional front surface to the back surface, utilizing the third dimension (depth/thickness) of the cell structure. This spatial reorganization allows simultaneous optimization of light absorption on the front and electrical collection on the back.
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 significantly reduces series resistance, enhances efficiency, and lowers manufacturing costs while improving the tolerance to hidden-cracks and micro-cracks, enabling high-performance and cost-effective industrial production of back-contact solar cells.
Implementation Method 1
the electrical connection layer comprises a number of small conductive gate lines, part of which are connected to the P-electrodes on the backlight side of the solar cells while the other part of which are connected to the N-electrodes on the backlight side of the solar cells
Implementation Method 2
Solar power generation is a process of power generation in which large-area P-N junction diodes are used to produce photon-generated carriers under the radiation of sunlight
Data Source
Figure 1~2
Figure 3a~4
Figure 5~6
AI summary
The present application relates to the field of solar cells, and in particular to a main-gate-free and high-efficiency back-contact solar cell module, assembly, and a preparation process thereof. The main-gate-free and high-efficiency back-contact solar cell module comprises solar cells and an electrical connection layer, a backlight side of the solar cells having P-electrodes connected to a P-type doping layer and N-electrodes connected to an N-type doping layer, wherein the electrical connection layer comprises a number of small conductive gate lines, part of which are connected to the P-electrodes on the backlight side of the solar cells while the other part of which are connected to the N-electrodes on the backlight side of the solar cells; and, the small conductive gate lines are of a multi-section structure. The present application has the following beneficial effects: the usage of silver paste is decreased, and the cost is reduced; moreover. The arrangement of small conductive gate lines in a multi-section structure reduces the series resistance and the transmission distance of a filling factor, so that the efficiency is improved and the stress on the cells from the small conductive gate lines can be effectively reduced.