Solar Cell Rear Surface Grooves for Carrier Collection

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Solution Overview

Problem

Existing solar cells face challenges in improving photoelectric conversion efficiency due to the need for enhanced surface morphology of film layers, particularly on the rear surface of N-type silicon substrates.

Innovation Solution

The solar cell design incorporates an N-type silicon substrate with a front surface featuring pyramid structures and a rear surface with sequentially arranged grooves, which improves the uniformity and specific surface area of the tunneling dielectric and doped conductive layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the rear surface of the N-type silicon substrate is kept flat, then the manufacturing process is simple, but the specific surface area and uniformity of the tunneling dielectric layer and doped conductive layer are insufficient

Engineering Contradiction:

Improvesimplicity of rear surface processingVSAvoidspecific surface area of rear surface

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent applies curvature by forming grooves with curved side walls on the rear surface of the N-type silicon substrate. These grooves increase the specific surface area compared to a flat surface, allowing for greater contact area between the tunneling dielectric layer and doped conductive layer with the silicon substrate, thereby improving passivation and carrier collection without significantly complicating the manufacturing process

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Area of stationary object

If the rear surface is textured with random patterns, then the specific surface area increases, but the uniformity of film layers deteriorates

Engineering Contradiction:

Improvespecific surface area of rear surfaceVSAvoiduniformity of film layer

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent segments the rear surface into multiple grooves with specific geometric patterns rather than using random texturing. This segmentation approach increases the specific surface area while maintaining uniformity, as the grooves are arranged in an ordered manner that allows for consistent film deposition and controlled etching processes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by creating grooves with specific local geometric features (width, depth, spacing) that are optimized for film layer formation. The grooves provide localized areas of increased surface area while maintaining overall uniformity through controlled distribution and geometry, enabling both enhanced surface area and consistent film quality

Inventive Principle:

Principle #3Local quality

3Productivity

If the contact area between electrode and doped conductive layer is increased, then carrier collection efficiency improves, but contact resistance increases

Engineering Contradiction:

Improvecarrier collection efficiencyVSAvoidcontact resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent creates a groove structure that effectively increases the contact area between the doped conductive layer and the silicon substrate without requiring a solid fill that would increase resistance. The grooves provide increased surface area for carrier collection while the doped conductive layer maintains low resistance through direct contact with the silicon substrate at multiple points along the groove walls

Inventive Principle:

Principle #31Porous 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

This configuration enhances the passivation effect and contact areas between electrodes and the doped conductive layer, reducing contact resistance and improving carrier collection efficiency, thereby increasing short-circuit voltage and photoelectric conversion efficiency.

Implementation Method 1

A solar cell is an apparatus that converts light energy of the sun into electric energy. The solar cell generates carriers by using a photovoltaic effect principle and introduces the carriers out by using an electrode

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentUS20250204079A1Solar cell, method for preparing the same and photovoltaic module

Publication Date: 2025.06.19 JINKOSOLAR MIDDLE EAST FZCO

AI summary

Embodiments of the present disclosure provide a solar cell and a photovoltaic module. The solar cell includes an N-type silicon substrate having a front surface and a rear surface opposite to the front surface. The front surface has a plurality of pyramid structures, the rear surface has a plurality of grooves, and at least one subset of the plurality of grooves is arranged sequentially along one arrangement direction. The solar cell further includes a passivation layer formed over the front surface, a tunneling dielectric layer formed on the rear surface, and a doped conductive layer formed over the tunneling dielectric layer. The doped conductive layer includes first portions and second portions formed at intervals, and the first portions include a N-type doping element and the second portions include a P-type doping element, or the first portions include a P-type doping element and the second portions include a N-type doping element.