Solar Cell Grid Electrode Fill Factor Optimization
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Solution Overview
Problem
Conventional solar cells have a high ratio of light-receiving surface electrode area to light-receiving area, leading to reduced power generation and lower open-circuit voltage due to increased series resistance and surface recombination velocity.
Innovation Solution
A method of manufacturing solar cells with a small-width grid electrode and a bar-shaped main electrode, using a screen method with a gauze or plate-shaped screen to form the grid electrode and a metal paste with excellent ohmic contact, and a paste with excellent solder wettability for the main electrode, to reduce electrode area and series resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the electrode area is reduced to increase the light-receiving area, then the light-receiving area contributing to power generation is increased, but the series resistance is increased
Solution Approach 1:
The patent changes the geometric parameters of the grid electrode by introducing a fill factor concept (ratio of grid electrode area to total cell area) and optimizing it to be 0.03-0.07. This parameter optimization allows minimizing electrode area while maintaining sufficient conductivity, resolving the contradiction between light-receiving area and series resistance
Solution Approach 2:
The patent introduces a new dimensional parameter - the fill factor - to systematically describe and optimize the electrode area ratio. By treating this as a design parameter rather than a fixed value, the patent enables precise control over the balance between light-receiving area and electrical conductivity
2Area of stationary object
If the grid electrode width is reduced, then the electrode area is reduced and light-receiving area is increased, but the manufacturing precision is reduced
Solution Approach 1:
The patent sets the fill factor within an optimized range (0.03-0.07) that corresponds to practical grid electrode widths manufacturable with conventional screen printing technology. This parameter range balances the need for small electrode area with the limitations of manufacturing precision in existing production processes
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 method results in a larger light-receiving area contributing to power generation with reduced series resistance, enhancing photoelectric conversion efficiency and increasing open-circuit voltage.
Implementation Method 1
forming a small-width grid electrode on a light-receiving surface of a substrate having a pn junction by firing a metal paste material
Implementation Method 2
forming a small-width grid electrode on a light-receiving surface of a substrate having a pn junction by firing a metal paste material; the grid electrode is formed by a screen method, in which a plate-shaped body including a small-width opening or a gauze having a thick film including a small-width opening formed by electrodeposition or adhesion is used as a screen
Data Source
AI summary
A solar cell attaining high efficiency in photoelectric conversion is provided. A method of manufacturing a solar cell having a grid electrode and a main electrode for external output of electric power from the grid electrode includes the steps of forming a small-width grid electrode on a light-receiving surface of a substrate having a pn junction by sintering a metal paste material, and forming a bar-shaped main electrode electrically connected to the grid electrode.