Half-cell modules are gaining an increasing market share due to their potential of increasing the module power without requiring any changes in the cell technology. However, it has turned out that different cell separation technologies can yield a similar electrical performance of the half-cells, yet leading to an entirely different mechanical behavior of the cells. Hence, the mechanical strength on solar cell and module laminate level was evaluated for thermal laser separation (TLS) and laser scribing with cleaving (LSC) cutting technologies on multicrystalline silicon Al-BSF solar cells. It could be systematically shown, that mechanical defects which are found on cell level can also be seen on module level. More precisely, the strength for the LSC batch was decreased by 35 % on cell level and 23 % on module level. The TLS process did not change significantly the strength on cell or module laminate level. Additionally, the origin of fracture was found at the edge for the laser batch and on the back side pads for the full cells and TLS cut cells. The electrical evaluation has shown minor electrical power losses of the half-cells leading to an efficiency reduction of less than 1 %_rel.

This paper reports the results of an international interlaboratory comparison study on light‐ and elevated temperature‐induced degradation (LETID) on crystalline silicon photovoltaic (PV) modules. A large global network of PV module manufacturers and PV testing laboratories collaborated to design a protocol for LETID detection and screen a large and diverse set of prototype modules for LETID. Results across labs indicate the reproducibility of LETID testing is likely within ±1% of maximum power (P_MP). In intentionally engineered LETID‐sensitive modules, mean degradation after the prescribed detection stress is roughly 6% P_MP. In other module types the LETID sensitivity is smaller, and in some we observe essentially negligible degradation attributable to LETID. In LETID‐sensitive modules, both open‐circuit voltage (V_OC) and short‐circuit current (I_SC) degrade by a roughly similar magnitude. We observe, as do previous studies, that LETID affects each cell in a module differently. An investigation of the potential mismatch losses caused by nonuniform LETID degradation found that mismatch loss is insignificant compared to the estimated loss of cell I_SC, which drives loss of module I_SC. Overall, this work has helped inform the creation of a forthcoming standard technical specification for LETID testing of PV modules, IEC TS 63342 ED1, and should aid in the interpretation of results from that and other LETID tests.

Photovoltaic modules in desert areas benefit from high irradiation levels but suffer from harsh environmental stress factors, which influence the Levelized Cost of Electricity by decreasing the lifetime and performance and increasing the maintenance costs. Using optimized half-cell module designs mounted in the most efficient orientation according to the plant requirements can lead to reduced production costs, increased energy yield and longer service lives for PV modules in desert areas. In this work, we review the technical advantages of half-cell modules in desert regions and discuss the potential gains in levelized costs of electricity due to reduced material consumption, a higher cell-to-module power ratio, lower module temperatures, better yields, reduced cleaning cycles and finally, reduced fatigue in interconnection due to thermal cycling. We show that half-cell modules are the most cost-effective option for desert areas and are expected to have a relevant lower Levelized Cost of Electricity.