Photovoltaic Sub-Cell I-V Characterization for Cutting Loss Analysis
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Solution Overview
Problem
The cutting of photovoltaic cells into sub-cells introduces localized defects and inhomogeneities, leading to current and voltage losses, and existing measurement methods cannot accurately quantify the impact of cutting on electric performance or differentiate between inhomogeneity and cutting-induced losses.
Innovation Solution
A method involving measuring the I-V characteristics of uncut cells, individual sub-cells, and an assembly of sub-cells connected in parallel to determine electric performance parameters, allowing for the calculation of differences that quantify the impact of cutting on electric performance and inhomogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If photovoltaic cells are cut into sub-cells to reduce current and resistive losses, then electrical conversion performance is improved, but localized defects and inhomogeneities are introduced causing current and voltage losses
Solution Approach 1:
The patent applies segmentation by dividing a photovoltaic cell into multiple sub-cells through cutting. This segmentation reduces the current flowing through each sub-cell and its interconnection strips, thereby reducing resistive losses (I²R losses). The cell is physically divided into N sub-cells, each with lower current requirements while maintaining the same total light-receiving surface area.
Solution Approach 2:
The patent changes the electrical parameters by altering the cell configuration from a single large cell to multiple smaller sub-cells. This parameter change affects the current density, voltage distribution, and resistance characteristics. The cutting process modifies the physical and electrical parameters, creating edges that require additional passivation to maintain reliability.
2Measurement precision
If individual sub-cell measurements are performed to quantify performance, then electric performance can be sorted and classified, but additional disparity related to inhomogeneity and cutting-induced losses cannot be differentiated
Solution Approach 1:
The patent adds another measurement dimension by performing I-V characteristics measurements on multiple configurations: the uncut cell, individual sub-cells, and the assembly of sub-cells connected in parallel. This multi-dimensional measurement approach enables differentiation between inhomogeneity effects and cutting-induced losses, providing comprehensive information that single measurements cannot provide.
Solution Approach 2:
The patent implements a feedback mechanism where measurement results from different configurations are used to calculate and quantify the impact of cutting. By comparing measurements from uncut cells, individual sub-cells, and assembled sub-cells, the system provides feedback on cutting quality, inhomogeneity levels, and performance losses, enabling process optimization and quality control.
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 method enables accurate quantification of performance losses due to cutting and inhomogeneity, ensuring continuous monitoring of cutting quality without reducing production line throughput, using minimal electronic equipment and existing measurement setups.
Implementation Method 1
The invention relates to the field of electrical characterization and measurement of the electric performance of photovoltaic sub-cells obtained by cutting a photovoltaic cell
Data Source
AI summary
A method for electrically characterising a cut photovoltaic cell, includes measuring the feature I-V of the uncut cell; cutting the cell into a plurality of sub-cells; measuring the feature I-V of each sub-cell not electrically connected to the other sub-cells; measuring the feature I-V of a set comprising all the sub-cells connected in parallel; determining, on the basis of the measured features I-V, performance parameters of the uncut cell, of each sub-set and of the set; computing, for each sub-cell, the difference between the value of the performance parameters of the sub-cell and that of the performance parameter of the uncut cell; and computing the difference between the value of the performance parameter of the set and the value of the performance parameter of the uncut cell.