LECO Silver Paste Composition for Low-Temperature TOPcon Contacts
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Solution Overview
Problem
Existing sintering technologies for N-type TOPcon solar batteries cause damage due to high temperatures, leading to reduced open circuit voltages and efficiency, necessitating the development of a conductive silver paste suitable for LECO technology to enhance photoelectric conversion efficiency.
Innovation Solution
A conductive silver paste comprising specific compositions of silver powder, glass powder, organic carrier, and inorganic additives, optimized for LECO sintering, which reduces glass and aluminum content, promotes silver-silicon contact, and enhances metallization contact to improve open circuit voltages and photoelectric conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sintering technology is used with high processing temperature exceeding 700°C, then sintering effect is achieved, but damage to batteries occurs and metal induced recombination increases, reducing open circuit voltages and overall efficiency
Solution Approach 1:
The patent changes the sintering temperature parameter from traditional high temperature (>700°C) to low temperature (70-150°C) process, fundamentally altering the thermal conditions to avoid battery damage while achieving effective sintering through LECO technology
Solution Approach 2:
The patent replaces traditional thermal sintering mechanism with LECO (Laser Enhanced Contact Optimization) technology that uses electrical current and laser energy to achieve sintering at lower temperatures, substituting the conventional thermal field with a combined electrical-optical field
2Reliability
If LECO sintering technology is used to reduce contact sintering temperature, then open circuit voltages and filling factor values increase, but specialized silver paste formulation is required which increases development complexity
Solution Approach 1:
The patent uses composite silver paste containing multiple components including silver powder (84.0%-92.0%), glass powder (0.5%-3.0%), organic carrier (6.5%-13.5%), and inorganic additive (0.2%-1.0%), where each component serves specific functions to achieve low-temperature sintering performance
Solution Approach 2:
The patent introduces glass powder with specific composition (Pb-Si-B-O-Ag system) that provides localized fluxing action and wetting properties at low temperatures, while inorganic additives provide localized catalytic effects to facilitate sintering without requiring high overall temperature
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 conductive silver paste achieves higher open circuit voltages, short-circuit currents, and photoelectric conversion efficiency improvements of 0.3% to 0.6% compared to traditional silver aluminum pastes, aligning with the requirements of LECO sintering technology.
Implementation Method 1
The LECO process involves using high-intensity laser pulses at a constant reverse voltage over 10V on the front surface of a solar battery, thereby resulting in a few amperes of current
Implementation Method 2
Solar batteries are effective tools for converting light energy into electricity using photovoltaic effect
Implementation Method 3
The present invention relates to the technical field of solar batteries, and in particular, relates to a conductive silver paste for sintering by LECO technology
Data Source
AI summary
The present invention discloses conductive silver paste for sintering by LECO technology, a preparation method, an electrode, and a battery. The conductive silver paste comprises silver powder, glass powder, organic carrier, and inorganic additive; in weight percentage, the weight percentage contents of these components are: silver powder 84.0%-92.0%, glass powder 0.5%-3.0%; organic carrier 6.5%-13.5%; inorganic additive 0.2%-1.0%; wherein the glass powder comprises main glass powder, the main glass powder is glass powder containing Pb, O, and first main element, second main element, and third main element systems; the first main element comprises at least Si, the second main element comprises at least B, the third main element comprises at least Ag. An N-type TOPcon battery manufactured by the conductive silver paste of the present invention has characteristics of a high opening voltage and high photoelectric conversion efficiency.