Photovoltaic Grid Lines With Width Gradient for Lower Optical Shading
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Solution Overview
Problem
The use of rectangular grid lines formed by copper electroplating in photovoltaic cells limits the reflection of incident light in multiple directions, reducing power generation efficiency and increasing assembling losses compared to circular arc-shaped grid lines.
Innovation Solution
A method involving coating a mask material on a solar cell precursor, exposing and developing a width gradient in the mask to form a mask opening, electroplating a metal in this opening to create a grid line with a width gradient, and optionally covering it with a reflecting or protective layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rectangular grid lines are formed by copper electroplating, then manufacturing cost is reduced and manufacturing precision is improved, but light reflection capability in multiple directions is limited and power generation efficiency decreases
Solution Approach 1:
The patent applies asymmetry by transitioning from symmetric rectangular grid lines to asymmetric circular arc-shaped grid lines. The circular arc shape creates non-uniform light reflection angles, enabling multi-directional reflection that improves power generation efficiency while maintaining copper electroplating manufacturing methods
Solution Approach 2:
The patent changes the geometric parameters of the grid line from rectangular to circular arc shape, specifically controlling the arc radius and curvature to optimize light reflection. This parameter change maintains the electroplating process while achieving improved optical performance
2Manufacturing precision
If rectangular grid lines are formed by copper electroplating, then manufacturing precision is improved, but optical width is increased and shading area is enlarged
Solution Approach 1:
The circular arc shape creates asymmetric light interaction where the effective optical width is reduced compared to rectangular lines of the same physical width. The curved geometry allows light to pass more easily at certain angles, effectively reducing the shading area while maintaining precise electroplating control
3Loss of energy
If circular arc-shaped grid lines are formed by silver paste printing, then light reflection in multiple directions is improved and power generation efficiency is increased, but manufacturing cost is increased
Solution Approach 1:
The patent replaces expensive silver paste with inexpensive copper material for grid line formation. By using copper electroplating with controlled circular arc geometry, the patent achieves the desired optical performance at lower material cost, effectively using a cheaper substitute material
Solution Approach 2:
The patent replaces the silk-screen printing mechanical process with copper electroplating. This substitution maintains the ability to form circular arc shapes while using a different, more cost-effective manufacturing mechanism that eliminates the need for expensive silver paste and silk-screen materials
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 grid line with a width gradient enhances light reflection at multiple angles, improving photoelectric conversion efficiency and reducing shading area, thus increasing power generation efficiency.
Implementation Method 1
exposing a local area of the mask according to properties of the mask, to form a development reaction area with width gradient in the mask
Implementation Method 2
electroplating a metal in the mask opening, to form the grid line with width gradient
Implementation Method 3
the circular arc-shaped grid line has a function of reflecting incident light at multiple angles, and the reflected light has a certain probability of being reflected back to a surface of a solar cell precursor
Data Source
AI summary
Disclosed are a photovoltaic cell and a preparation method therefor. The preparation method includes preparing a grid line of the photovoltaic cell by the following steps: coating a mask material over a front surface and/or back surface of a solar cell precursor, and curing the mask material to form a mask; exposing a local area of the mask according to properties of the mask, to form a development reaction area with width gradient in the mask; developing the mask in the development reaction area, to form a mask opening with width gradient in the development reaction area; electroplating a metal in the mask opening, to form the grid line with width gradient; and removing the mask. The optical width of the grid line is reduced to improve the photoelectric conversion efficiency of the photovoltaic cell.