Lead Bar Connection to Conductive Ribbon in Thin Film PV
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Solution Overview
Problem
Existing photovoltaic module manufacturing processes face challenges in establishing a robust, automated electrical connection between conductive ribbons and transmission lines, which is costly and unreliable, and introduces mechanical defects such as holes that compromise the integrity of the back panel, making it susceptible to damage from impacts like hail.
Innovation Solution
The solution involves a thin film photovoltaic device design with a solid lead bar extending through a small connection aperture in the encapsulation substrate, allowing for direct electrical connection to the conductive ribbon via a meltable conductive material, enabling automated assembly and enhanced mechanical integrity by filling the aperture with conductive material, thereby reducing the risk of damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large hole is introduced to access the conductive ribbon for electrical connection, then the electrical connection can be established, but the mechanical integrity of the back panel is compromised
Solution Approach 1:
The patent extracts the electrical connection function from the mechanical structure by using a separate lead bar that passes through the back panel independently of the conductive ribbon extraction method. This allows the ribbon to remain intact while still achieving electrical connection through the lead bar.
Solution Approach 2:
The lead bar serves as an intermediary element that bridges the electrical connection between the conductive ribbon and the external circuit. Instead of directly extracting and connecting the ribbon, the lead bar mediates this connection by passing through the back panel and making contact with the ribbon internally.
2Reliability
If the conductive ribbon is pulled up through a hole and cut to create tabs for connection, then electrical connection can be made, but the process becomes difficult to automate
Solution Approach 1:
The patent segments the electrical connection system into distinct functional components: the conductive ribbon remains in place on the front, the lead bar provides the connection path through the back panel, and the sealant provides the sealing function. This segmentation allows each component to be optimized independently and facilitates automated assembly.
Solution Approach 2:
Instead of pulling the ribbon up through the hole to create tabs (traditional approach), the patent inverts the approach by passing the lead bar through the hole and making contact with the ribbon that remains in its original position. This inversion simplifies the manufacturing process and enables automation.
3Strength
If the hole in the back panel is mechanically reinforced to correct the integrity issue, then the strength is improved, but an additional process step and part are added
Solution Approach 1:
The patent merges multiple functions into the lead bar component: it provides structural support at the hole location, serves as the electrical connection conductor, and acts as a mechanical anchor for the sealant. This consolidation eliminates the need for separate reinforcement elements and additional process steps.
Solution Approach 2:
The lead bar serves multiple functions simultaneously: it provides mechanical reinforcement at the aperture location, establishes the electrical connection pathway, and serves as an anchor for the sealant material. This multi-functionality reduces the overall complexity by eliminating the need for separate components for each function.
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 design enhances the mechanical integrity of the photovoltaic device by minimizing the aperture size, increasing shatter resistance, and allowing for automated assembly of the junction box, reducing the likelihood of damage from impacts and streamlining the manufacturing process.
Implementation Method 1
The meltable conductive material can then be heated to electrically connect the first conductive ribbon to the first lead bar via the meltable conductive material.
Data Source
AI summary
Thin film photovoltaic devices that include at least one lead bar extending through a connection aperture defined in the encapsulation substrate are provided. The photovoltaic device can include: a transparent substrate; a plurality of photovoltaic cells on the transparent substrate; a first conductive ribbon electrically connected to a first photovoltaic cell; an encapsulation substrate laminated to the transparent substrate such that the plurality of photovoltaic cells and the conductive ribbon are positioned between the transparent substrate and the encapsulation substrate; and, a first lead bar extending through a first connection aperture defined in the encapsulation substrate. The first lead bar is electrically connected to the first conductive ribbon. For example, a meltable conductive material can be connected to the first lead bar and to the first conductive ribbon to establish an electrical connection therebetween. Methods are also provided for electrically connecting a lead to a thin film photovoltaic device.