Solar Cell Busbar and End-Portion Electrode Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The connection of solar cells with conductive leads in solar cell modules often results in cracking or chipping at the end portions, leading to reduced yield during the production process due to vertical pressure applied during module assembly.
Innovation Solution
A solar cell design featuring busbar electrodes and thicker end-portion electrodes on the backside of the semiconductor substrate, which are separated from the busbar electrodes, allowing conductive leads to connect obliquely and reducing direct pressure on the end portions, thus preventing cracking and chipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive leads are soldered to connect solar cells vertically, then electrical connection between solar cells is achieved, but cracking or chipping occurs at end portions of solar cells reducing yield
Solution Approach 1:
The conductive lead connection structure is segmented into three parts: a first electrode on the front surface, a busbar electrode on the back surface, and a pad at the end portion. This segmentation allows the pad to be positioned away from the solar cell end, preventing direct contact between the conductive lead and the vulnerable end portion of the solar cell, thereby eliminating cracking while maintaining electrical connectivity.
Solution Approach 2:
The pad acts as an intermediary element between the busbar electrode and the conductive lead connection point. By extending the conductive path to the pad located at a distance from the solar cell end, the intermediary structure transfers the electrical connection function away from the vulnerable end portion, preventing mechanical damage while ensuring reliable electrical connection.
2Reliability
If conductive leads extend vertically to connect solar cells, then electrical connection is established, but direct pressure on end portions causes damage during assembly
Solution Approach 1:
The connection structure transitions from a vertical alignment (directly above the solar cell end) to a lateral extension (away from the end portion along the back surface). By changing the spatial dimension of the pad position from vertical to lateral, the conductive lead connects to a point that does not transmit assembly pressure to the solar cell end, thereby improving durability.
3Ease of manufacture
If busbar electrode is positioned close to end portions for connection, then manufacturing is simplified, but cracking occurs reducing yield
Solution Approach 1:
The pad is pre-positioned at a specific distance from the solar cell end portion before the conductive lead attachment process. This preliminary positioning ensures that when the conductive lead is subsequently attached to the pad, it will not contact the vulnerable end portion of the solar cell, thereby preventing cracking while maintaining manufacturing simplicity.
Data Source
AI summary
To improve the yield of a solar cell in its production process, a solar cell includes a semiconductor substrate including a first main surface and a second main surface corresponding to the backside of the first main surface, a busbar electrode on a line extending in a first direction on the second main surface, and end-portion electrodes each being an extension of the busbar electrode on the second main surface and separated from the busbar electrode, and each of the end-portion electrodes having a larger thickness than that of the busbar electrode.