Change in electrical specification of PC8 Series

Transcription

1 Title Change in electrical specification of PC8 Series Year 2012 Team Technical Assurance Date Author Moontaek Lim Open Date 3 Years Reviewed Jaekyong Yoo Close Date Approved Koo Lee I. Definition II. Product change followed by Market Trend III. Understanding error for performance simulation IV. Characteristics and Superiority of SM-xxxPC8 Series Table of Contents 1. Intrinsic Characteristics of PC8 Model 2. Difference between PC8(Old model) and PC8(New Model) a. Improvements b. Tcoe comparison c. PR comparison V. Conclusion S-ENERGY CO., LTD. 3RD FL., MIRAE ASSET TOWER 685, SAMPYEONG-DONG, BUNDANG-GU, SEONGNAM-SI, GYEONGGI-DO, SOUTH KOREA This report is published to demonstrate the excellence of SM-XXXPC8 Series, despite partial changes in

2 electrical specification I. Definition This report suggests the readers to briefly understand the terms and fomulars below. Category Full Name Detail Tcoe Temperature coefficient Relative change in Pmax, in solar generation, when temperature of PN connection of an element alters by 1, Temperature coefficient for a module is usually affected by the cell, and can be partially affected when combining and processing raw/submaterials. NOCT Nominal Operating Cell Temperature - Irradiance on cell surface : 800W/ - Ambient Temperature : 20 - Wind speed : 1m/s - Mounting : Open back side STC Standard Test Condition - Irradiance on cell surface : 1000W/ - Module Temperature : 25 - Air mass : 1.5 PTC PVUS Test Condition - Irradiance on cell surface : 1000W/ - Ambient Temperature : 20 - Wind speed : 1m/s - Mounting : Open back side PR Performance Ratio - II. Product change followed by Market Trend

3 1. Market demand and problems of current module technology Recent market demand continuously pursues high-output products based on the assumption of maintaining long-term creditability. However, electrical performance of modules develops in a slower pace than the market demand. In fact, only partial characteristics, not the whole, have been improved. 2. Changes in electrical specification of cells and modules S-ENERGY is, therefore, investing in R&D to continuously develop product quality, and on the same line, the company is focusing on development of individual electrical specification to upgrade its Field output. However, characteristic of a complete product is closely related to features of its sub-materials, and often R&D for the module only is meaningless. The below table shows how the Temperature coefficient Pmax data of the cell that S-ENERGY uses, manufactured by XXX company, has changed and how difficult it is to control the Tcoe Pmax. S-ENERGY controlled Tcoe Pmax equivalent to the cell s one in the past. Recently, S- ENERGY has improved NOCT to supplement and reduce loss in power generation. 3. Sub-material Trend According to recent rapid price drop in the market, all manufacturers in PV industry are suffering from its depression and module manufacturers particularly are facing with risk that loss could occur at the same time of production; therefore, costs on raw materials are seriously being considered and continuously discussed with suppliers. In this regard, raw material manufacturers have been leading cost reduction in the market while making quality level reasonable and appropriate from excessive quality level in the past. As a result, sub-materials are getting thinner and even its raw materials are being replaced. But users should be cautious of this change and are recommended to use a reliable company s product, because to use unproven product can cause serious damage to module s life.

4 III. Understanding Error for Performance Simulation Customers are using a variety of tools to calculate power generation so as to get better ROI. But it is essential to have a right understanding on the meaning of Simulation and these simulation tools. All the measuring systems have their own errors. For instance, in case of simple measurement for power performance of the module, Fraunhofer clearly mentions error range of ±2% in its test reports. And among the testing labs, they show difference measured values even far out of the error range. This is not because of testing labs but Measurement contains its own errors in the word. For that reason, it is advised Simulation Tool to be used as rough calculator for power generation before making investment decisions, not a perfect measurement. Furthermore, since actual figures of each important factors deciding power performance are subject to change by test facilities, environmental and test conditions, actual measurement can be far off the mark of error range than expected. Therefore, it is certain to compare simulation data for each module based on one standard, tested by the same lab at the same time. In fact, S-ENERGY purchased modules from Top 10 suppliers listed on Photon Magazine and analyzed them on actual Tcoe Pmax value. In case of Mono type was which is 19.6% lower than the value of shown on their datasheet. For Poly type, it was which is 23.2% lower than the value of In conclusion, our test might show actual measured figures of them or as mentioned earlier, be caused by testing method, testing facilities and environmental factors. In other words, it is too early to judge power performance based on the measurement from Simulation tool alone.

5 IV. Characteristics and Superiority of SM-xxxPC8 Series Module manufacturers are under heavy pressure by both customer s demands on a certain characteristic and sub-materials continuous technical changes. Therefore, modules are manufactured through internal investigation on credible data from sustainable and reliable suppliers. In this process, module specification is subject to change. Regardless of whether the change looks good or not, it is obvious that overall product performance have been improving. Let s take a look at how the SM-xxxPC8 Series has been improved and changed. 1. Intrinsic Characteristics of PC8 Model a. Reduction of Direct Resistance - Increase in Sectional Area of Electric Connection Line : PC8 Series have been improved to reduce direct resistance giving more efficiency by increasing cross section area of Ribbon connecting to the cell.(interconnector 20%, Busbar 33% increase) - Elimination on the V-type fracture of the Busbar : minimize heating and eliminate dangerous factors causing Hot Spot., b. Expansion of interval from Cell to Frame - Modules are installed on fixed angle to absorb the sun light, but this causes accumulation of rain or dirt that makes shades on the bottom of modules. In order to prevent possibility of module damage such as output drop or J/Box overloads, 82% of expansion of interval from cell to frame was applied. c. Strength Increase -Changes on structure of the cross section area to prevent possibility of glass breakaway have upgraded stability. (XXXPC8 Series Hole type Frame/ MLT 8400Pa Pass)

6 2. Difference between PC8(Old model) and PC8(New Model) a. Improvements -PC8(New Model) has realized high power output through the improvement on electrical connectors, and it gives more stable power generation for products with low output by reducing overheating through stable capacity on connectors. -With increasing insulpatch thickness by 22%, Insulation in Cell and Busbar has improved in stability terms. -NOCT has been improved by 2 degrees (4.4%) through application of sub-materials which have better protection against heat. As shown on pictures below, PC8(New Model) temperature is 3 degrees lower than PC8(Old Model) in the same test condition of time and temperature. Ambient Temp. Average Temp. Max Temp. 240PC8 (Old Model) PC8 (New Model) Furthermore, problem on De-lamination caused by humidity has been solved through the new B/S(Back Sheet) ending process method of Double Waterproof structure.

7 b. Tcoe Comparison As the recent market demands high performance and efficiency, the technical development in the PV industry is focusing on improving Pmax. For instance, the higher max output of the motor vehicle is, the more power needed. In the end, it can lead to larger fuel consumption. To take an example of motor vehicle, the higher power output generally requires larger fuel consumption which is to be concerned a lacking factor. In other words, an improvement may lead to a diminishing of other factors. The PV module is not an exception of the mechanism; factors are influenced by other factors and those variables are mainly rectified through improving cells and sub-materials. In other words, it is too early to make a hasty conclusion that one defective factor cause product s overall performance worse. PC8(New Model) has Tcoe Pmax worse than before, but its Tcoe Isc, Tcoe Voc and NOCT have been improved, and as the table below shows there is even higher improvement in terms of the percentage change. Item Old New Differnce Remark Tcoe Isc % Higher is better Tcoe Voc % Lower is better Tcoe Pmax % Lower is better NOCT 47±2 45±3 95.7% Lower is better Furthermore, if we see the certificate authority s test report on NOCT alone, it has excellent figures as below. Nevertheless, in order to provide our clients with more stable figures considering regional difference and measurement deviation, we are indicating NOCT of 45±3%.

8 c. PR(Performance Ratio) Comparison For Performance Ratio becoming customers major concern, S-ENERGY has tested PR simulation between PC8 Old and New Model. As a result, the difference on PR is very small, and PC8(New Model) slightly shows better performance in the test. However, it is important to take into account that the simulation is only a tool to estimate generated amount, and even each figure used for PR simulation may have over 10% error in measured value terms. Germany Munich NOCT Output(kWh/year) PR(%) NOCT Output(kWh/year) PR(%) Diff.(kWh) Diff.(%) PR(%)

9 V. Conclusion Since current simulation tools are largely used for estimating power generated amount, it is necessary to evaluate modules based on cases and data of actual power generation, and not on simple specification. Solar industry nowadays focuses on high efficiency and long-term reliability, but on the other hand, rapid price drop has been continuing due to oversupply in the market. Therefore, R&D direction for PV modules and submaterials is being processed along this tendency, as well as PC8 Series. R&D scheme always changes to produce better and reliable product than the past. Although there have been changes in electrical specification in the New PC8 version, but it possesses same power output as the older one and is developing to a much advanced product in a long-term reliability. Additionally, S-ENERGY is in the process of creating new warranty for the output drops in the fields, enhancing durability in deteriorated regions, and developing the product that can generate power in special conditions such as desert.