Interconnection Sheet Wiring Pattern for Solar Cell Void Reduction
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Solution Overview
Problem
Solar cell modules with back electrode type solar cells often suffer from air voids in the sealing material, leading to inadequate bonding, thermal stress, and increased risk of electrical short circuits due to metal ion migration, particularly when exposed to high temperatures.
Innovation Solution
An interconnection sheet with a specific wiring pattern on an insulating base material, featuring alternating arrays of strip-shaped wires for n-type and p-type electrodes, which allows for efficient electrical connection and includes gaps to facilitate gas discharge, reducing voids and enhancing module reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the insulating base material is meshed and sealing material is pressed and heated to introduce space between the back electrode type solar cell and the insulating base material, then bonding strength is improved, but gaseous voids remain in the sealing material causing reliability deterioration
Solution Approach 1:
The patent extracts the harmful gaseous voids from the sealing material by providing dedicated discharge paths (spaces between wiring patterns and edge regions) that allow gases to escape during the sealing process. This extraction principle resolves the contradiction by maintaining bonding strength while eliminating the reliability-deteriorating voids.
Solution Approach 2:
The patent converts the potentially harmful gaseous voids into a beneficial discharge mechanism. By intentionally designing spaces in the wiring pattern, the gases that would otherwise cause reliability issues are channeled through controlled paths to the edge regions, transforming the harm into a controlled release process that improves overall module reliability.
2Strength
If gaseous voids remain in the sealing material between the back electrode type solar cell and the insulating base material, then bonding strength is reduced, but electrical connection between electrode and wiring becomes unsatisfactory
Solution Approach 1:
The patent extracts gaseous voids from critical bonding regions by providing discharge paths that redirect gases away from the interface between the back electrode type solar cell and the insulating base material. This ensures both strong bonding and reliable electrical connection by preventing void formation in these critical areas.
3Stability of the object's composition
If the solar cell module is exposed to high temperature environment, then thermal expansion of gaseous voids causes stress that tears apart wiring and electrode, but the module structure remains fixed
Solution Approach 1:
The patent extracts gaseous voids that would otherwise expand and cause thermal stress. By providing discharge paths during the sealing process, the structure is prevented from developing internal gas pockets that would expand at high temperatures and tear apart the wiring and electrode connections.
Solution Approach 2:
The patent performs preliminary action by creating discharge paths for gaseous voids before the high-temperature exposure occurs. The spaces between wiring patterns and edge regions are pre-configured to allow gas escape during sealing, preventing the formation of voids that would later expand and cause damage under thermal stress.
4Reliability
If gaseous voids remain in the sealing material, then water vapor enters and metal ions migrate, but the wiring and electrode connection becomes unsatisfactory
Solution Approach 1:
The patent extracts gaseous voids that would otherwise serve as pathways for water vapor penetration and metal ion migration. By providing discharge paths during sealing, the structure is freed from internal voids that would compromise connection reliability through moisture ingress and electrochemical migration.
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 effectively reduces gaseous voids within the solar cell module, improving bonding strength and reliability by allowing gas discharge through exposed gaps, thus preventing thermal stress and electrical issues.
Implementation Method 1
the sealing material will be introduced through the mesh of the meshed insulating base material into between the back electrode type solar cells and the wiring and thus cure to seal the back electrode type solar cells
Implementation Method 2
the gaseous voids remaining in the sealing material between the back electrode type solar cell and the insulating base material thermally expand, which causes a stress in a direction to tear apart the wiring on the insulating base material and the electrode of the back electrode type solar cell
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
An interconnection sheet (10), a solar cell with the interconnection sheet, a solar cell module, and an interconnection sheet roll satisfy a relationship of Y ≤ Z < X, where X represents a maximum linear distance in a first direction (50) from a connection portion (21a) connecting a wire for n type (12) and a first connecting wire (14a) to a connection portion (21b) connecting a wire for p type (13) and a second connecting wire (14b), Y represents a maximum length of an alternating array portion (20) in the first direction (50), and Z represents a maximum length of the alternating array portion (20) in a second direction (51). Furthermore, a solar cell with an interconnection sheet, and a solar cell module have a gap (18) between an end of the wire for n type (12) at the opposite side of the first connecting wire (14a) and the second connecting wire (14b) and between an end of the wire for p type (13) at the opposite side of the second connecting wire (14b) and the first connecting wire (14a), the gap (18) being exposed from a perimeter of a back electrode type solar cell (30).