Maxwell Introduces New Perovskite-HJT Tandem Turnkey Cell Line

At the Perovskite Technology, Equipment and Materials Forum held in Suzhou, China, PV cell production equipment maker Suzhou Maxwell Technologies Co. Ltd., introduced its latest turnkey line for perovskite-HJT tandem PV cell technology.  

Maxwell says this platform uses the know-how gained in building plate-type vacuum deposition tools, such as Plasma-Enhanced Chemical Vapor Deposition (PECVD) and Physical Vapor Deposition (PVD), among others. PECVD is primarily used to fabricate the HJT bottom cell at low temperatures, while PVD is used for depositing the conductive thin layer of Transparent Conductive Oxides (TCOs). These vacuum deposition platforms ensure a low wafer breakage rate, minimal downtime, and high production stability, claims the company, citing its experience supplying more than 3,000 tools, typically for HJT cell manufacturing. 

This turnkey line features a metallization technology in which the metal contacts (P-side grid lines) are screen-printed onto the substrate before the perovskite film is applied, contrary to the standard end-of-line metallization process. Calling it ‘Pre-Printing technology’, the company states that it eliminates the potential risk of exerting pressure on the finished, fragile perovskite stack and mitigates the chances of defect formation. In addition, it reduces overall materials and their costs by using Maxwell’s HJT printing equipment and lower-silver-content silver/silver-copper paste. The company claims that these attributes help achieve a 0.5% to 1.0% increase in cell efficiency; however, the press release didn’t specify whether this is in relative or absolute terms. 

The company adopted Inkjet Printing technology for the perovskite wet process. Compared to the standard spin-coating method, which coats the entire substrate, this digital technique deposits target materials only where needed, helping achieve material utilization of over 95%. Additionally, it results in consistent film thickness, integrity (like prevention of pinhole defects), conformality with the underlying textured bottom cell surface, and edge control along the cell with high-resolution patterning. 

Following the deposition of the perovskite absorber layer, the company’s ‘EAP INLINE’ tools work in a continuous transfer mechanism or an inline process sequence. Here, the ‘EAP’ prefix indicates 3 key vacuum processing steps: Evaporation (E), ALD (A), and PVD/PED (P), each responsible for depositing different charge transport layers. Maxwell claims that the attributes of inline processes, such as faster wafer handling and elimination of exposure to atmospheric conditions, among others, help achieve 3 times the throughput of its batch-type peers. It added that it selected the temporal ALD between the temporal and spatial route. 

Unlike the standard thermal furnace-based sintering process for metallization grid lines, the company uses photon sintering. It uses an intense, controlled-spectrum pulse of light for a certain duration so that the metal paste absorbs the light energy rapidly and selectively. The company states that it maintains a temperature differential of over 30°C between the paste and wafer. It adds that this selective, localized heating meets both ends of reducing grid resistance and preventing thermal damage to the perovskite layer, while enhancing cell efficiency. However, Maxwell didn’t quantify this efficiency gain in its press release. 

In addition, this platform reduces the construction volume of a low-humidity room by integrating ‘key utilities’ within the cell line. This also reduces the operational costs of heating, ventilation, and air-conditioning (HVAC). 

According to the company, this turnkey tandem cell line offers an annual production capacity of up to 200 MW (G12 half-cut cells). However, it offers capacity flexibility with a lab line (20 to 50 MW), a pilot line (100 to 200 MW), and a mass production line (500 to 600 MW).