Fine Line Dispensing Process to apply Narrow Metal Contacts onto Solar Cells

Project Information

HighLine

Grant agreement ID: 190146412

DOI

10.3030/190146412

Project closed

EC signature date 11 January 2023

Start date 1 February 2023

End date 31 May 2025

Funded under

• The European Innovation Council (EIC)

Total cost

€ 3 575 916,25

EU contribution

€ 2 500 000,00

Coordinated by

HIGHLINE TECHNOLOGY GMBH
Germany

Periodic Reporting for period 2 - HighLine (Fine Line Dispensing Process to apply Narrow Metal Contacts onto Solar Cells)

Reporting period: 2024-02-01 to 2025-05-31

Summary of the context and overall objectives of the project

HighLine Technology GmbH (ISE spin-off from Fraunhofer Institute for Solar Energy Systems) holds exclusive IP to redefine the metallization process for applying silver contact lines on Si-solar cells. Metallization is the 2nd most expensive production step, with the PV industry consuming >14% of global silver demand. Current PERC cells are limited to 23.5% efficiency and €0.05/kW cost, while more efficient Heterojunction cells (HJT, >26% efficiency) require over double the silver, hindering adoption.
HighLine’s EIC Accelerator project streamlines solar cell manufacturing through Fine Line Parallel Dispensing Printing Technology, a breakthrough metallization process, replacing the 30-year-old screen-printing method. Using multi-micro-nozzle printheads, it extrudes silver with finest line widths (<17 μm), achieving homogeneous finger grids. Benefits include: 25% silver savings, +1% relative efficiency gain (reduced shadowing), 50% higher throughput at 800 mm/s printing speed (vs. flatbed screen-printing).
In a project amendment WP4 was adapted towards application of the parallel dispensing technology for cell interconnection via electrically conductive adhesives (ECA), for low-temperature cell concepts that can’t use soldering. Dispensing enables: Homogeneous structures down to 200 μm, Closed-system advantages over screen/stencil printing, Compatibility with future cell concepts (e.g. XBC), allowing ECA + adhesives combinations impossible with conventional methods.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

WP1: project management tasks were effectively planned and implemented, with progress and achievements monitored against technical & commercial objectives. Proper project & financial management procedures & tools were established, with regular monitoring of legal & financial matters, including IPR protection.
WP2: pre-commercial actions were efficiently conducted, with a Communication & Dissemination Plan set to continue beyond project end.
WP3: HighLine dispensing technology successfully integrated into Applied Materials’ industrial platform (leading Western equipment manufacturer), with continuous refinements to software interfaces, calibration routines & workflows; the optimizations prepared the printing platform for presentation to a joint beta customer after the initial alpha testing phase.
WP4: HighLine’s dispensing technology was successfully integrated into Mondragon Assembly’s stringer platforms (leading automation provider), yielding promising technical results & initial joint sales. The combined interconnection system is being deployed at leading EU research institutes.
WP5: significant progress achieved in advancing the pre-industrial maturity of HighLine dispensing system, including improvements in valve performance, calibration routines & precision component manufacturing. Operator support was enhanced via targeted software development & essential quality assurance processes were successfully implemented. Although the exit of several Western paste suppliers caused a temporary setback, a contingency plan to establish an alternative European supply chain has delivered promising results.
WP6: with EIC project support, a modular production line was developed for cleaning, assembly & quality assurance of high-precision components for system integration. The platform features automated routines for handling tight-tolerance parts & ensures consistent process control across the assembly workflow.
The modular architecture of the line allows future scalability & expansion, ensuring volume & quality requirements for successful market launch.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

HighLine project offers a unique alternative process for the PV cell metallization, without any screen-printing steps involved. It is a breaktrough metallization technology for HJT cells, but also disruptive to streamline current PERC(TopCon) or perspectively Perovskite-Tandem production lines and also has been demonstrated for further fields of applications along the PV-value chain like interconnection in module production.
The technology has demonstrated outstanding potential & benefits, by reducing resource input (Ag or AgCu paste), optimising cell performance and even achieving higher throughput, all contributing to decreasing Levelised Cost of Electricity (LCOE).
# HighLine USPs vs Screen-Printing metallization: 20% material savings (Ag or AgCu); 1% rel. cell efficiency gains; 50% higher throughput (depending on automation).
# HighLine printing speed (800mm/s) vs. Screen-Printing (400 mm/s); two nozzle rows in series vs. one blade. 30% higher effective conductivity due to homogeneous lines; <17μm contact finger width (vs. 28μm); Contactless printing (wafer thickness improvement) vs. Mechanical pressure via a squeegee (that can lead to microcracks).
# HighLine USPs of metallization technology: Precise dispensing with tiny nozzles (nozzle diameter <25μm); Intermittent parallel operation of multi-nozzle printheads (200 nozzles).
# Other benefits: Compatible with HJT & PERC & TopCon; Compatible with commercial/new pastes; Retrofitting integration; Closed-off paste supply enables different paste solvent systems, less drying energy demand and prevents oxidation/aging until printed.
# Two component (Adhesive/Conductive Adhesive) printing for module interconnection without curing step in between enabling next generation Back-contact cell concepts.
HighLine Technology has already demonstrated the competitive advantage of the metallization process. Throughout the project HighLine has matured the underlying technology and components for industrial application, established collaborations with established market players and integrated the technology into industrial production platforms. The European PV ecosystem and value chains have decreased during the project-term causing challenges especially for the preidentified risk of paste availability. HighLine responded with a customized formulation/collaboration approach initiated by its shareholders complementing technology offer and decreasing dependencies. The formulation will eventually require OEMs for manufacturing of paste in high volumes.

HighLine Technology

HighLine Dispensing Printhead installed in automation platform