Busbar-Free Back Contact Cell Layout to Prevent Finger Shorting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The risk of short circuits in busbar-free back contact cells due to conduction between fingers of opposite polarity is a significant challenge.
Innovation Solution
The busbar-free back contact cell design includes alternately distributed current-confluence and non-current-confluence regions on the cell substrate, with insulating members covering fingers of opposite polarity and conductive members in electrically connected regions to facilitate same-polarity connections, reducing the risk of short circuits and eliminating the need for busbars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fingers of two polarities are alternately distributed on the back surface to collect current, then current collection efficiency is improved, but the risk of short circuits between opposite polarity fingers increases
Solution Approach 1:
The back surface is segmented into current-confluence regions and non-current-confluence regions through patterned insulating members. This segmentation allows fingers of opposite polarity to be physically separated into different regions, enabling efficient current collection while preventing short circuits between opposite polarity fingers.
Solution Approach 2:
Insulating members are introduced as intermediary elements between fingers of opposite polarity. These insulating members (with thickness 10-50 μm) act as mediators that prevent direct electrical contact between opposite polarity fingers while allowing the fingers to maintain their alternately distributed configuration for efficient current collection.
2Reliability
If insulating members are added to prevent short circuits, then short circuit risk is reduced, but device complexity increases
Solution Approach 1:
The insulating members serve multiple functions simultaneously: they provide electrical insulation between opposite polarity fingers, define current-confluence and non-current-confluence regions, and facilitate the connection structure for conductive members. This merging of functions reduces the need for additional separate components, thereby limiting the increase in device complexity.
Solution Approach 2:
The insulating members are designed with multi-functionality: they act as electrical insulators, region delimiters, and structural support elements for conductive members. This universal design allows a single component to address multiple requirements, minimizing the overall complexity increase despite adding insulation capability.
3Productivity
If conductive members are arranged in electrically connected regions to connect same polarity fingers, then series connection efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The insulating members are pre-patterned to define electrically connected regions before conductive members are added. This preliminary action creates predetermined zones where conductive members will be placed, ensuring accurate positioning for series connections while simplifying the subsequent manufacturing process.
Solution Approach 2:
The insulating members create localized electrically connected regions with specific properties (conductivity, connectivity) that are different from surrounding areas. This local quality differentiation ensures that conductive members placed in these regions automatically achieve proper electrical connection with same polarity fingers, reducing the overall precision requirements.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present disclosure is applicable to the technical field of solar cells, and provides a busbar-free back contact cell (100), a cell module and a photovoltaic system. The busbar-free back contact cell (100) includes a cell substrate (10), first insulating members (21) and conductive members, wherein alternately distributed fingers of two polarities are formed on the back surface of the cell substrate (10), the back surface includes alternately distributed current-confluence regions (13) and non-current-confluence regions (14), and parts of each finger are located in the current-confluence regions (13), and the rest parts of each finger is located in the non-current-confluence regions (14); the current-confluence regions (13) include electrically connected regions (101), and the first insulating members (21) are arranged in the current-confluence regions (13) and cover fingers having a polarity opposite to that of the current-confluence regions (13) to expose the electrically connected regions (101); and the conductive members are arranged in the electrically connected regions (101).