Photovoltaic Cell Solder Layer Preforming for Reliable Interconnection
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Solution Overview
Problem
Current photovoltaic modules face reliability issues due to false soldering or unsoldering between connecting members and solder pads, leading to instability in electrical connections and increased risk of conductive foreign matter formation during the manufacturing process.
Innovation Solution
A method for manufacturing photovoltaic modules involves forming a solder layer on each solder pad, comprising a first alloy layer adjacent to the pad and a second alloy layer on its surface, with a tin-based alloy, to reduce the spacing between connecting members and solder pads, thereby enhancing the stability and reliability of electrical connections. This method includes heating the soldering treatment to a temperature between 200°C to 300°C for a duration of 1.2s to 1.9s, using a tin feeder or tinning machine to accurately control the solder layer thickness and area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder paste is used to connect connecting members and solder pads, then electrical connection is achieved, but false soldering or unsoldering occurs easily and reliability deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-forming a solder layer on the solder pad before assembling the connecting member. This pre-formed solder layer ensures proper wetting and bonding conditions are already in place, preventing false soldering or unsoldering issues that occur when using solder paste during assembly. The solder layer is created in advance with controlled thickness and material composition to guarantee reliable electrical connection.
Solution Approach 2:
The patent changes the material parameters by replacing traditional solder paste with a specifically designed solder layer made from tin-based alloy materials. The solder layer has controlled thickness (5-50 μm) and specific material composition (Sn-Pb, Sn-Ag, or Sn-Cu alloys), which improves wetting properties and bonding strength compared to conventional solder paste, thereby enhancing connection reliability and manufacturing precision.
2Strength
If high temperature heating is used for soldering, then connecting members are securely attached, but cell performance deteriorates due to thermal damage
Solution Approach 1:
The patent changes the material parameters by using a solder layer with specific alloy composition (Sn-Pb, Sn-Ag, or Sn-Cu) and controlled thickness (5-50 μm). This material optimization allows the soldering process to achieve adequate bonding strength at lower temperatures (150-250°C) compared to traditional high-temperature soldering, thereby reducing thermal damage to the photovoltaic cell while maintaining connection strength.
3Ease of manufacture
If solder paste is used for connection, then assembly is simplified, but conductive foreign matters are generated and process control becomes difficult
Solution Approach 1:
The patent applies preliminary action by pre-forming a clean, controlled solder layer on the solder pad before assembly. This pre-formed layer eliminates the need to use solder paste during assembly, thereby preventing the generation of conductive foreign matters that occur with solder paste application. The solder layer is created with precise thickness control (5-50 μm) and proper material composition, ensuring clean connections without contamination while maintaining ease of manufacture through automated lamination processes.
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 pre-formed solder layer improves the stability and reliability of connections between connecting members and solder pads, reduces the probability of false soldering, and minimizes the risk of performance damage from high temperatures, resulting in safer and more reliable photovoltaic modules with reduced conductive foreign matter formation.
Implementation Method 1
a first alloy layer adjacent to the respective solder pad and a second alloy layer on a surface of the first alloy layer away from the respective solder pad, and the first alloy layer including a first alloy formed of tin and a metal element constituting the respective solder pad
Implementation Method 2
coating each solder pad with molten solder for forming the corresponding solder layer after cooling
Implementation Method 3
coating each solder pad with molten solder for forming the corresponding solder layer after cooling
Implementation Method 4
performing a soldering treatment on the respective connecting member and the respective pair of adjacent cells to connect the respective pair of adjacent cells, wherein the soldering treatment has a heating temperature in a range of 200°C to 300°C
Data Source
Figure 1
Figure 2~3A
Figure 3B~4
AI summary
Embodiments of the disclosure provide a method for manufacturing a photovoltaic module and a photovoltaic module. The method includes the following: providing a plurality of cells; selecting at least one cell from the plurality of cells, and for each respective cell of the at least one cell, forming a corresponding solder layer on each respective solder pad of at least one solder pad of the respective cell; and performing a soldering treatment on the respective connecting member and the at least one solder pad and/or the at least one solder layer to connect the respective pair of adjacent cells, wherein the soldering treatment has a heating temperature in a range of 200°C to 300°C.