Solar Cell Adhesion Enhanced Layer
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Solution Overview
Problem
Conventional solar cells face challenges in enhancing adhesion between the back electrode layer and the substrate, leading to potential cracks and short circuits during the tabbing process, and in optimizing light reflection for improved power generation efficiency.
Innovation Solution
Incorporating an adhesion enhanced layer made of intrinsic amorphous or microcrystalline silicon between the back passivation layer and the back electrode layer, with a metal-silicon alloy interface, and a diffusion barrier layer to prevent aluminum diffusion, which improves adhesion and reflectance, reducing the risk of cracks and enhancing power generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional back electrode structure is used without an adhesion enhanced layer, then the device complexity is reduced, but the adhesion between the back electrode layer and substrate deteriorates, leading to potential cracks and short circuits
Solution Approach 1:
An adhesion enhanced layer comprising intrinsic amorphous silicon and intrinsic microcrystalline silicon is introduced between the back electrode layer and the substrate. This intermediate layer acts as a mediator that significantly improves adhesion strength, preventing cracks and short circuits during the tabbing process while maintaining reasonable structural complexity.
Solution Approach 2:
The adhesion enhanced layer utilizes a composite structure combining intrinsic amorphous silicon and intrinsic microcrystalline silicon. This composite material approach leverages the complementary properties of both silicon forms to achieve optimal adhesion enhancement between the back electrode layer and substrate.
2Power
If the back electrode layer is directly formed on the substrate, then the manufacturing process is simplified, but light reflection is insufficient, reducing power generation efficiency
Solution Approach 1:
The adhesion enhanced layer serves a dual function as an intermediary: it enhances mechanical adhesion while simultaneously improving optical performance. The layer's refractive index (3.7-4.2) creates effective light reflection at the back surface, increasing power generation efficiency without significantly complicating the manufacturing process.
Solution Approach 2:
The invention optimizes the refractive index parameter of the adhesion enhanced layer (3.7-4.2) to maximize light reflection. By controlling the optical parameters of the intermediate layer, the system achieves improved light trapping and reflection, thereby enhancing power generation efficiency.
3Reliability
If aluminum diffusion is not prevented, then the device structure is simpler, but the electrical performance deteriorates due to aluminum diffusion into the substrate
Solution Approach 1:
A diffusion barrier layer is introduced as an intermediary between the back electrode layer and the substrate. This layer effectively prevents aluminum diffusion into the substrate, maintaining electrical performance stability and reliability while adding only moderate structural complexity.
Solution Approach 2:
The diffusion barrier layer selectively extracts or blocks the harmful aluminum diffusion pathway while allowing the beneficial electrical connection to be maintained through the adhesion enhanced layer. This separation of functions ensures electrical performance stability without excessive structural complexity.
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 solution enhances the adhesion between the back electrode layer and the substrate, preventing cracks and short circuits, while optimizing light reflection to improve solar cell efficiency and reduce manufacturing costs.
Implementation Method 1
an adhesion enhanced layer positioned between the back electrode layer of the second electrode and the back passivation layer, the adhesion enhanced layer containing at least one of intrinsic amorphous silicon and intrinsic microcrystalline silicon
Implementation Method 2
The adhesion enhanced layer may include a metal-silicon alloy layer at an interface between the adhesion enhanced layer and the back electrode layer. The metal-silicon alloy layer formed at the interface between the adhesion enhanced layer and the back electrode layer may be an aluminum-silicon alloy layer.
Implementation Method 3
The solar cell may further include a diffusion barrier layer positioned between the back passivation layer and the adhesion enhanced layer. The diffusion barrier layer may contain silicon nitride (SiNX).
Implementation Method 4
The back passivation layer may contain at least one of aluminum oxide (AlOx), silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiOxNy).
Data Source
AI summary
A solar cell includes a substrate, an emitter region positioned at a first surface of the substrate, a first electrode positioned on the first surface of the substrate, a back passivation layer positioned on a second surface opposite the first surface of the substrate, and a second electrode which is positioned on the back passivation layer and is electrically connected to the substrate through holes of the back passivation layer. The second electrode includes connection electrodes positioned inside the holes of the back passivation layer and a back electrode layer positioned on the connection electrodes and the back passivation layer. An adhesion enhanced layer is positioned between the back electrode layer and the back passivation layer and contains at least one of intrinsic amorphous silicon and intrinsic microcrystalline silicon.