Next Generation Revolutionary in PERC Cell Technology – n-Type Cells Are Rapidly Mass Production
Apr 08, 2022
High temperature, irradiation and low humidity
LeTID - High Temperature Assisted Light Induced Decay, when a photovoltaic cell is exposed to sunlight in an environment with a temperature above 50°C, the photocurrent causes the triggering of excess charge carriers. For some susceptible modules, it can cause up to 10% power loss, especially PERC solar cells.
Initial results from PVEL's LeTID testing suggest that LeTID may be widespread. LeTID has all but replaced Potential Difference Induced Decay (PID) as the newest and most recent form of decay that investors and asset owners must avoid.
For the same modules, the photovoltaic modules installed in Cyprus have a power loss of 7% in three years, and a power loss of 2.5% in Germany. The biggest difference is temperature, irradiation and humidity. In FraunHofer's method for LeTID testing of components, the components are placed in an environmental test chamber at 75°C, with a humidity below 10%, and a DC power supply is supplied with a weak current for 162 hours.
High temperature, high irradiation, and low humidity, isn't this the typical climate environment in the deserts and Gobi regions of northern China? In the layout of China's latest large-scale scenery bases, during the 14th Five-Year Plan period, the four deserts of Kubuqi, Ulan Buhe, Tengger and Badain Jaran will plan to install 128GW of new energy.
Without solving LeTID, how dare to invest in photovoltaic power plants in deserts and Gobi?
Don't be afraid, n-type is coming
As the next generation of revolutionaries in PERC cell technology, n-type cells are rapidly mass-produced.
For n-type batteries, the current mainstream representative technologies include TOPCon, HJT heterojunction, and IBC. China's leading photovoltaic companies are generally optimistic about TOPCon and HJT. The former represents companies such as Jinko, JA Solar, and Tianhe, and the latter represents companies such as Risheng, Huasheng, Akcome, etc., and Tongwei and Canadian Solar are in the two companies. Together technically. IBC batteries are mainly led by Maxeon in the United States. SPIC Yellow River has a 200MW IBC trial production line. Aixu was optimistic about IBC but recently stopped its IBC financing project.
In the face of LeTID, are n-type batteries not afraid?
The Fraunhofer ISE in Germany recently conducted a LeTID test of IBC solar modules to check their power loss under constant bright light or high temperature. The researchers chose the same company's IBC modules and traditional PERC modules for comparison. After 324 hours of testing in an environment of 75°C and 10% humidity, they found that all IBC modules had extremely low decay rates.
According to the LeTID test standard discussion draft of IEC TS 63202-4 (1 sun, 75±2°C, 168 hours), JinkoSolar has tested typical crystalline silicon cell LeTID attenuation. 1%, and the linear attenuation is less than 0.4%, which has won wide attention in the industry.
Based on laboratory conditions, n-type cells and components that have just been produced have the characteristics of "zero decay" or even "negative decay". Jinko's data also supports this theory with a LeTID decay of -0.3% tested for n-type TOPCon.
A large base for scenery, n-type has a great role to play
At the time when PERC and n-type battery technologies overlap and replace, the scenery base is like a timely spring rain, which provides a wide range of uses for n-type batteries.
Taking the power attenuation advantage of n-type technology over p-type PERC technology, in the outdoor application environment of 25 to 30 years, the power attenuation of n-type components will be 2.6 percentage points lower than that of p-type components, which is equivalent to a 3% increase in issuance.
The advantages of n-type technology will be more pronounced in desert regions with lower humidity, higher temperatures and more sunlight.
The new generation of n-type replaces the old generation of PERC. From the perspective of previous technology replacement, it often takes 2-3 years for the new technology to gradually occupy the market dominance. The planning of the Fengguang Base Project may change the process of replacing old and new technologies due to the performance index of LeTID, which may explain to a certain extent why the current n-type battery and module production expansion is so fierce.
