LONGi Solar: LONGi Solar is a world leading manufacturer of high-efficiency mono-crystalline solar cells and modules.

LONGi has announced that its Module Testing Centre in Taizhou has been awarded Proficiency Testing Laboratory status by China’s National Institute of Metrology (NIM), the nation’s highest research facility for measurement science and a national statutory authority in the field of metrology.

Under its full name of “Proficiency Testing Program for Measurement of Key Photoelectric Parameters of Monofacial / Bifacial PV Modules”, the testing program is organized by the NIM (CNAS proficiency testing provider, PT0037) and the China Quality Certification Center (CQC). The program covers measurement of photoelectric parameters for high-efficiency PV modules and aims to compare and verify the technical capacity of relevant laboratories in the PV measurement and testing field in China to measure key performance parameters under standard testing conditions. Running from July to November 2020, testing involved a total of four optional module items (two monofacial and two bifacial), and evaluated a total of 35 major third-party testing organizations, PV enterprise laboratories and equipment manufacturers.


The procedure involved NIM testing data related to LONGi’s 144mm half-cut wafer size monocrystalline monofacial PERC module, 72mm full wafer size monocrystalline bifacial PERC module (front face) and 144mm half-cut wafer size monocrystalline bifacial PERC module (front face), all in strict accordance with IEC standards 61215-2:2016 and 60904-1:2006. All three modules were classified as “satisfactory” (the testing has only three classifications – “satisfactory”, “problematic” and “not satisfactory”), and LONGi performed particularly well among the participating laboratories.


Over a number of years, LONGi has obtained positive results in proficiency testing, both at home and abroad:


In May 2018, the company secured TÜV Rheinland laboratory accreditation


In September 2018, the company received certification from China’s National Accreditation Service for Conformity

Assessment (CNAS), its laboratory then holding double certification qualification in the PV field in China. In the

same year, LONGi obtained a “Proficiency for Testing of Photoelectric Performance of High-Efficiency PV Modules”

certification from NIM (CNAS proficiency testing provider, PT0037) and CQC.






In 2019, when the American laboratory RETC issued its “PV Module Index” for the first time, LONGi became one of

only two companies to receive a “High Achiever” award from among the 46 global companies participating, due to

its modules’ excellent performance across 18 indexes in terms of reliability, performance and quality.

In 2020, in the “All Quality Matters” Solar Congress hosted by TÜV Rheinland, LONGi received “Outdoor Energy

Yield” awards in both bifacial and monofacial groups.


Behind LONGi’s achievements is the company’s unswerving commitment to innovation and sustainable development. As the solar company with the world’s largest market value at present and a leader in monocrystalline technology, LONGi has been leading the PV industry in the pursuit of product transformation and LCOE optimization, and the classification of “general excellence” given to LONGi’s laboratory in the proficiency testing program is recognition of the company’s product management and laboratory testing capabilities.