Notwithstanding its importance, output power may no longer serve as the common ground while evaluating modules of different technologies and brands. Unlike in the past, where there has been more or less a standard wafer size and cell count, today's market is flooded with various wafer and module formats.
And the PV industry today is more open to experimenting with the number of cells per module to better meet specific application needs as opposed to the traditional choices of 60 or 72 cells. As a result, today's PV panels are available with a wide range of power ratings and dimensions. In this context, power density is a handy metric to evaluate module products based on different technologies and configuration. While efficiency also provides output power versus module area, power density provides a greater resolution of the "area factor" of the module. It is a more straightforward method to compare modules based on different technologies and configurations.
In fact, ITRPV is advocating a sophisticated alternative expression called "Area Efficiency" for power density. Its 11th roadmap emphasizes that n-type back contact modules had the highest area efficiency of about 210 W/m2 in 2019 and would reach 220 W/m2 by 2022, while the next 10 W/m2 improvement would take another 8 years. HJT technology, having area efficiencies below the level of back contact modules until 2022, is expected to take the lead by 2027 and reach 238 W/m2 in 2030, the highest level estimated in the roadmap. As for the current state of the art technology, PERC, ITRPV assess that the area efficiency of these modules would surge eventually from 203 W/m2 in 2020 to 225 W/m2 over the next 10 years.
For the purposes of our research for commercially available module products with high power density, we set the cutoff at 210 W/m2, which narrowed the list to 22 products from 18 module makers. And it is not surprising that the list is similar to the efficiency listing. Maxeon's back contact modules have the highest power density of about 226 W/m2, followed by HJT from Suntech and a TOPCon module from Jolywood with 221.5 W/m2 and 220 W/m2, respectively. In the PERC segment, GCL takes the top spot again with a power density of 219.6 W/m2. As for module technologies, 4 IBC cell-based panels are naturally built with advanced back contact module technology and the rest employ both half cells and MBB. The exceptions are LG's NeON 2 TOPCon module using only MBB and JinkoSolar's Tiger Pro series using Tiling Ribbon technology that, in addition to half cells and MBB, also involves gapless interconnection layout.
For more information on trends in power densities and 500 W+ commercially available high power modules, please download the TaiyangNews report on Advanced Module Technologies 2021, which is accessible for free here.
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