Researchers from KETI and UNSW demonstrated rapid cell separation using electromagnetic induction
A modified glass-to-glass module achieved separation in 5.4 seconds at 200 A, with over 99.8% component recovery by mass
The study also examined the heating response of bifacial PERC, TOPCon, and HJT cells, exploring the method's potential across different cell architectures
Researchers from the Korea Electronics Technology Institute (KETI) and the University of New South Wales (UNSW) have developed an inductive heating-assisted method for recycling crystalline silicon PV modules.
The method uses electromagnetic induction to heat the solar cells' metallic electrodes. When an alternating current passes through an induction coil, the resulting magnetic field heats the conductive metal components. The rapidly heated cell transfers heat to the adjacent EVA layer. At temperatures exceeding approximately 350°C, the acetate groups in EVA begin to decompose and form acetic acid. The resulting gas expands at the cell-encapsulant interface, weakening the adhesion and eventually causing the solar cell to detach. Because the heating is concentrated near the interface, most of the EVA remains largely intact.
The researchers used p-PERC type solar cells with a rear-side full-area aluminum electrode for their experiments. They first investigated the heating mechanism through simulations and experiments using a simplified, rear-less module structure. This consisted of a solar cell laminated between a layer of EVA and a single sheet of tempered glass, without a rear glass sheet or polymer backsheet. The samples were placed above an induction coil, with the glass side facing the coil and the solar cell positioned above it. The researchers tested different coil currents to examine their effect on heating and delamination. At 100 A, the solar cell temperature rose much faster than the glass, with a temperature difference exceeding 200°C. The cell began to separate from the encapsulant after approximately 8-10 s. When these samples were tested inverted (suspended above ground at the edges), with silicon facing down, complete separation occurred at 14 s, causing the sample cell to fall.
These tests were also extended to rear-less modules using POE, showing similar detachment results. These experiments were also performed on glass-glass laminated cell samples, which made it harder for gases generated after EVA decomposition to escape. We used an edge-release film made of polytetrafluoroethylene (PTFE) in the non-cell region before lamination to avoid this. The modified module was then suspended in a supporting jig, allowing gravity to assist cell separation. These modules required separation times of 18.6 s at 100 A, 8.3 s at 150 A, and 5.4 s at 200 A.
The researchers also evaluated the recovery of the separated components. They reported over 99.8% component recovery by total module mass. The average component mass retention immediately after delamination, before residual EVA extraction, was 99.94%.
One important point is that this modified setup is not used in mainstream modules. Therefore, the exact method may not be suitable for use on commercial modules. Additionally, the team also examined the thermal response of other cell architectures, including bifacial PERC, TOPCon, and heterojunction (HJT) cells. However, these tests focused on their heating behavior under induction rather than demonstrating the complete module recycling process for each technology.
The complete research publication titled Inductive heating for photovoltaic module recycling and near-complete component recovery can be accessed here.
