#LSSEU: JinkoSolar’s Carlos Magistris discusses solar module reliability and efficiency
Before next week Large-scale virtual summit of the Solar EUPV Tech speaks with Carlos Magistris, Senior Technical Manager Europe at JinkoSolar Europe to discuss some of the key issues related to the reliability and performance of solar modules.
Module quality and, perhaps more importantly, reliability have recently become important issues for research and development in the solar field. What steps have module manufacturers like JinkoSolar taken to improve this?
In terms of quality standards, by using multi-busbar technology (MBB), we have increased the stability and reliability of the cell and reduced mechanical stress, effectively avoiding the risk of micro-cracks. MBB also reduces the distance between the main busbars, which means that the electron transport distance as well as the current loss are reduced.
A round tape welding strip can speed up the use of light and improve low-level performance. To be more specific on the manufacturing side, the following procedures are used to avoid micro-cracks:
one. Along with the aforementioned circular ribbon, our TR technology allows us to control the ribbon thickness of the overlap area by improving the ribbon pressing process and measuring the ribbon thickness on a regular basis.
b. Straight Belt Before Pressing: Make sure the belt stays straight and its hardness before you press it, and that the press machine stays horizontal.
c. Temperature control: additional AC power is added during the belt press process. Carefully control the pressing temperature to make sure the seat is lower than the melting point of tin.
After all, the conduction of heat between the cells using Tilling Ribbon technology is faster than between the cell and the ribbon. Therefore, the heat conduction of the TR modules is more uniform when the hot spots occur. Hence, the Tiger Pro modules work better and avoid the problem of hot spots.
What kind of improvement in project return do these innovations and R&D advances have and what impact do they have on project developers?
Jinko’s new ultra-high-efficiency modules, Tiger PRO, are based on a half-cut cell design to reduce cell current mismatch and ribbon loss. In addition, Multi-Busbar and Tiling-Ribbon (TR) technology reduces the distance between the main busbar and the finger grid lines, reducing resistance loss and increasing the output power and efficiency of the module while maintaining a low open circuit voltage (Voc) .
The module’s low voc and temperature coefficient (-0.35%) can increase the number of modules at the unit group string level. Knowing the DC-side capacity of the project can reduce the total number of strings in the project, which increases power densities. As a result, supply-scale systems can reduce the amount of DC cabling, PV mounting and combination boxes required, thereby lowering BOS (Balance of System) costs.
In addition, the higher efficiency reduces the area required for the same peak power, as well as the wind and snow loads, which indirectly helps to lower the cost of fixtures for the mounting system. Further advantages of the Tiger PRO module series are the premium guarantee. For monofacial Tiger PRO modules, a deterioration of no more than 2% in the first year and a deterioration of no more than 0.55% in the second to 25th year is planned.
One of the more obvious introductions is bifaciality – what do project developers need to keep in mind when considering bifacial panels for their projects?
As bifacial technology takes hold in the market, costs are likely to drop further to become even more competitive with monofacial, which will have a significant impact on financial models. Rather than a revolutionary technology, bifacial generation sees a gradual improvement over a proven technology that takes much less time to collect enough data to model validation and bankability metrics.
In general, important aspects are optimizing the design and installation to avoid shadows on the back and to take over most of the technology. Then of course the choice of the right bifacial technology. The modules with the transparent backsheet option are an interesting option, as they address most of the shortcomings of the dual-glass technology. For example, a transparent back panel can withstand the effects of UV rays hitting the back of the modules much better than the standard double-glazed modules. The transparent backsheet modules also solve important problems with double-glass bifacial modules, increasing the module’s potential even further, primarily for large utility-scale projects where reduced LCOE and improved IRR and maximizing plant performance are critical .
Transparent backsheet modules are also better suited and are suitable for project designs that require lightweight modules. In this way, thanks to the lower weight and the simpler installation method of the panel, which is comparable to conventional framed modules with a glass back wall, BOS (Balance of Systems) costs can be achieved.
One of the key trends this year has been the introduction of high power modules with power greater than 550W. What is the expected impact on project yield given the impact on the size / weight of the physical module and its electrical properties?
With the dawn of the grid parity era, the industry has recognized the benefits of using large sized, high performance modules for their ability to reduce LCOE. However, larger modules are associated with greater technological challenges.
The 182mm modules effectively support the existing industrial specifications and electrical system. The benefits are also mainly determined by the production costs, transportation costs / restrictions and the analysis of the project financial costs.
In terms of the LCOE, 182 seems like the best option as they offer high levels of generation capacity and reliability, optimal for large ground power plants. When comparing different dimensions of electricity costs, BOS costs and IRR, 182 mm products are simply the better choice.
From a logistical point of view, the width of a wafer-based module of 182 mm reaches the size limit of a standard-size container, which has a positive effect on shipping costs. After all, the 182mm module is the main product with the highest market share and production capacity forecast for the coming years.
The large-scale virtual solar EU summit will take place from November 24th to 26th, 2020. For more information on registering for the event, see found here.