Photovoltaic Cell Electrode Pad Layout for Thermal Shrinkage Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Photovoltaic cells face deformation and damage due to shrinkage of electrode lines during thermal expansion and cold contraction, leading to warping and reduced operational stability and service life.
Innovation Solution
The design includes a semiconductor substrate with a passivation layer, busbars, and electrode pads, where the vertical distance between the electrode pad and the passivation layer (L1) is greater than or equal to the distance between the busbar and the passivation layer (L2), creating a gap between the electrode line and the busbar, which allows for natural straightening of the electrode line and reduces deformation risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode line is directly connected to the busbar without a gap, then the electrical connection is more direct and resistance is lower, but the electrode line shrinks during thermal expansion and cold contraction causing deformation and damage to the photovoltaic cell
Solution Approach 1:
The electrode pad serves as an intermediary component between the electrode line and the busbar. By positioning the electrode pad at a height L1 that is greater than or equal to the busbar height L2, a gap is created that allows the electrode line to naturally bend and straighten during thermal cycles without transmitting shrinkage forces to the busbar or semiconductor substrate, thus preventing deformation while maintaining electrical connection.
Solution Approach 2:
The solution introduces a vertical dimension (height difference L1-L2) between the electrode pad and the busbar to resolve the horizontal thermal shrinkage problem. By creating a gap in the thickness direction, the electrode line is given spatial freedom to accommodate thermal expansion and contraction without causing planar deformation or damage to the photovoltaic cell structure.
2Object-affected harmful factors
If the electrode line is allowed to have natural bending, then thermal stress is reduced, but the electrical connection stability may be compromised
Solution Approach 1:
The elevated electrode pad acts as a mediator that decouples the thermal deformation of the electrode line from the structural components. The gap created by L1≥L2 allows the electrode line to bend naturally during thermal cycles while the electrode pad maintains stable electrical connection to the busbar, thus simultaneously reducing thermal stress and preserving connection stability.
3Device complexity
If the busbar is positioned closer to the electrode line, then the structure is more compact, but the electrode line shrinkage causes warping of the semiconductor substrate
Solution Approach 1:
By utilizing the vertical dimension to create a height difference between the electrode pad (L1) and the busbar (L2), the design allows the electrode line to have sufficient clearance to bend during thermal cycles. This vertical separation prevents the horizontal shrinkage forces from causing the electrode line to pull on the busbar and warp the semiconductor substrate, while still maintaining a relatively compact overall structure.
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 reduces the risk of deformation and damage to the photovoltaic cell, improving operational stability and extending the service life by accommodating thermal changes without warping.
Implementation Method 1
After the electrode line and the electrode pad are soldered and fixed and is cooled to room temperature, a naturally bending portion of the electrode line is straightened under thermal expansion and cold contraction
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present disclosure relates to a photovoltaic cell and a photovoltaic module. The photovoltaic cell includes a semiconductor substrate, a passivation layer arranged on surface of the semiconductor substrate, busbars and electrode pads arranged on the passivation layer. Each of the electrode pads is configured to be electrically connected to electrode line, and along a thickness direction of the photovoltaic cell, the electrode pad is arranged on a side of the busbar away from the passivation layer, or arranged on the passivation layer, the busbar includes connection lines spaced apart along first direction, and adjacent connection lines are electrically connected through electrode pad. Along thickness direction of the photovoltaic cell, vertical distance between a highest point of electrode pad and surface of the passivation layer is L1, and vertical distance between the busbar and the surface of the passivation layer is L2, where L1 and L2 satisfy L1≥L2.