The LID+LETID results are better than ever, with a 0.43% median and 0.4% average degradation when combining the average LID value and the average LETID value for each BOM produced in 2023. This has resulted in the Top Performer threshold being raised to 1% for this test. See the Power Degradation graph below for more.
LID + LETID
The PQP’s Light Induced Degradation (LID) and Light and Elevated Temperature Induced Degradation (LETID) tests quantify these cell-based phenomena that are often incorporated into energy yield models. LID varies by cell technology, but primarily impacts boron-doped cells and stabilizes shortly after module deployment. LETID most predominantly affected early generation PERC cells and is more severe in hotter climates. Degradation from LETID reaches its maximum point after months or years.
Key
Takeaways
96% of BOMs tested had < 1% power loss.
Low LID and LETID degradation across cell technologies.
The median power loss for LID+LETID was 0.3% for gallium-doped p-type PERC and 0.2% for n-type cell technologies (TOPCon, HJT and xBC), showing that these technologies are generally not susceptible to these degradation modes. And while this is good news for the industry, UVID power loss is a growing concern.
CID and LID values are not statistically correlated thus far.
In November 2023, Kiwa PVEL launched the latest PQP which includes CID preconditioning on the LETID samples rather than LID. Across the limited number of BOMs tested, the CID and LID results have shown weak correlation, with some BOMs well aligned (±0.2% of each other), but another BOM had >1% between CID and LID.
Pre-stress testing failures continue to be problematic.
For the second Scorecard in a row, the most frequent failure category was pre-stress testing failures. 26% of manufacturers experienced at least one pre-stress testing failure, including missing junction box lids, peeling nameplate labels, wet leakage testing failures, delamination and diode failures. See the Failures page for more.
Test Result Spotlight
The graph below displays the average LID and LETID results for each BOM in the 2024 Scorecard dataset, separated by PERC and n-type (TOPCon, HJT and xBC) technologies. There are minimal differences across the cell technologies: the median post-LID power loss was 0.38% for PERC and 0.43% for n-type; and post-LETID, PERC had a 0.09% median power loss and n-type had a 0.19% median power gain. Most notable is the power recovery seen on many BOMs post-LETID. This is likely due to an artifact of the cell stabilization processes (e.g., LETID mitigation) that are common amongst some cell manufacturers.
LID and LETID results for each BOM in the 2024 Scorecard dataset, separated by cell technology. Note that according to the module manufacturers, only one of the PERC BOMs was doped with boron and it is not the lowest performer. All other p-type PERC BOMs were doped with gallium.
Power Degradation of LID+LETID BOMs
A case study on why LID and LETID is important, what PV module materials are assessed, and the test procedure can be found here on kiwa.com/pvel.
See LID + LETID Top Performers
Click here to see the 345 model types listed as LID + LETID Top Performers.
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