Back Contact Solar Cell Edge Passivation for Minority Carrier Collection
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Solution Overview
Problem
Existing back contact solar cells have low collection efficiency of minority carriers at the edge, which hinders improved operating efficiency.
Innovation Solution
A back contact solar cell design with a semiconductor substrate featuring a non-electrode collecting region and an electrode collecting region, where a majority carrier passivation layer with a greater thickness than the doped semiconductor portion is used to form a minority carrier inversion layer, reducing carrier recombination and enhancing carrier collection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a back contact solar cell structure is used to increase light receiving surface area, then light utilization and photoelectric conversion efficiency are improved, but minority carrier collection efficiency at the edge is reduced
Solution Approach 1:
The patent applies local quality by creating a non-electrode collecting region at the edge of the front surface with a majority carrier passivation layer having different properties (greater thickness) compared to other regions. This localized structural modification addresses the specific problem of poor minority carrier collection at the edge while maintaining the overall back contact structure's high light utilization efficiency.
Solution Approach 2:
The patent introduces a new spatial dimension by creating a non-electrode collecting region at the edge perimeter of the front surface, which is a different dimension from the traditional back surface electrode arrangement. This dimensional extension allows minority carriers generated at the edge to be collected through a dedicated path without recombination losses.
2Productivity
If the majority carrier passivation layer thickness is increased to reduce carrier recombination, then operating efficiency is improved, but device complexity increases
Solution Approach 1:
The majority carrier passivation layer is applied with greater thickness specifically in the non-electrode collecting region at the edge rather than uniformly across the entire surface. This localized approach reduces carrier recombination where it matters most while avoiding unnecessary complexity and material usage in regions where it is not needed.
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 design improves the collection and transmission of minority carriers to adjacent doped semiconductor portions, reducing recombination and increasing the overall efficiency of the solar cell.
Implementation Method 1
form a minority carrier inversion layer on an inner side of a semiconductor substrate at an edge of a first surface through a majority carrier passivation layer
Implementation Method 2
Under an action of an electric field of the majority carrier passivation layer, the minority carrier inversion layer repels photogenerated minority carriers
Implementation Method 3
A solar cell is an apparatus that can convert sun's light energy into electric energy. Specifically, when the solar cell is in an operating state, sunlight irradiates onto a semiconductor p-n junction of the solar cell to form new hole-electron pairs
Implementation Method 4
sunlight irradiates onto a semiconductor p-n junction of the solar cell to form new hole-electron pairs. Under an action of a built-in electric field of the p-n junction, photogenerated holes flow to a p-type region, and photogenerated electrons flow to an n-type region, so that a current can be generated
Data Source
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AI summary
The present application discloses a back contact solar cell and a manufacturing method thereof, and a photovoltaic module, and relates to the field of photovoltaic technologies, to form a minority carrier inversion layer at an edge of a first surface through a majority carrier passivation layer and arrange the majority carrier passivation layer with a relatively great thickness in a non-electrode collecting region, so as to reduce carrier recombination at the edge of the first surface. The back contact solar cell includes a semiconductor substrate, a first doped semiconductor portion, a second doped semiconductor portion, and a majority carrier passivation layer. A first surface includes a non-electrode collecting region located at an edge and an electrode collecting region located on an inner side of the non-electrode collecting region. The electrode collecting region includes minority carrier regions and majority carrier regions distributed alternately and at intervals along a first direction. Along the first direction, an outermost minority carrier region is closer to the non-electrode collecting region than an outermost majority carrier region. The first doped semiconductor portion is arranged in the majority carrier region. The second doped semiconductor portion is arranged in the minority carrier region. The majority carrier passivation layer is arranged in the non-electrode collecting region. A thickness of the majority carrier passivation layer is greater than a thickness of the second doped semiconductor portion.