Potential-induced degradation of n-type front-emitter crystalline silicon photovoltaic modules — Comparison between indoor and outdoor test results

Field‐representative evaluation of PID‐polarization in TOPCon PV modules by accelerated stress testing

“…On the other hand, as PV system voltage increases to reduce system cost, modules would need to be designed more robustly and tested to the levels of those system voltages to avoid PID driven by the increasing voltage potential. The extent of PID-p evaluated here under the factors of voltage bias, irradiation, and temperature is significantly less than that reported in the field for n + /n fronts of interdigitated back contact cell modules (20% power loss) 4 and p + /n front emitters of PERT modules (15% power loss) 8 that have a similar p + /n front emitter structure as the TOPCon modules examined here. We may speculate, in accordance with previous PID studies on TOPCon-type modules, 10 that the industry migration from SiN x /SiO 2 /p + /n (as reported in 8 ) to SiN x A-lO x /p + n passivating dielectrics and emitters in modern TOPCon modules 27 may provide better stability to PID-p stress from voltage bias with illumination.…”

“…The extent of PID-p evaluated here under the factors of voltage bias, irradiation, and temperature is significantly less than that reported in the field for n + /n fronts of interdigitated back contact cell modules (20% power loss) 4 and p + /n front emitters of PERT modules (15% power loss) 8 that have a similar p + /n front emitter structure as the TOPCon modules examined here. We may speculate, in accordance with previous PID studies on TOPCon-type modules, 10 that the industry migration from SiN x /SiO 2 /p + /n (as reported in 8 ) to SiN x A-lO x /p + n passivating dielectrics and emitters in modern TOPCon modules 27 may provide better stability to PID-p stress from voltage bias with illumination. One possible reason is that AlO x contains a built-in negative fixed charge that repels minority carrier electrons from recombining at the front surface, 28 counteracting to some extent the developing positive charge from the PID stress.…”

“…4,5 The charge that causes PID-p may be dissipated by illumination, especially within the ultraviolet (UV) range, based on the photoconductivity of dielectrics used in the passivating antireflective coating, which has primarily been studied for silicon nitride. [5][6][7] There are several reports of PID-p in the field, 4,8 including an instance where field performance decreased 20% after several months of operation. 4 The extent and rate of PID-p recovery under illumination may vary between PV cell technologies.…”

Second-stage potential-induced degradation of n-type front-emitter crystalline silicon photovoltaic modules and its recovery

“…Finally, we discuss the second-stage PID, FF reduction, of n-FE c-Si PV modules in actual outdoor operation. Since we have observed the FF reduction of n-FE c-Si PV modules operated in outdoor condition, 31) possible measures for the suppression of the second-stage PID should be considered. Positive-bias application and/or heating can recover the FF of n-FE c-Si PV modules, as shown in Figs.…”

“…[5][6][7][8][9][10][11][12] On the other hand, detailed studies on the PID for the n-type c-Si PV modules are insufficient and need to be investigated furthermore. [13][14][15][16][17][18][19] We have thus far investigated the PID of n-type c-Si PV modules 20) with cells such as rear-emitter, 21) front-emitter (FE), [22][23][24][25][26][27][28][29][30][31] interdigitated back-contact, 32) and Si heterojunction structures. [33][34][35][36][37] Of those, n-type FE (n-FE) c-Si PV modules have been investigated in the most detail.…”