Solar cells or photovoltaic cells are the building blocks of photovoltaic modules also known as solar panels. These solar panels are often used to convert the solar energy into electricity and are preferred by many due to its eco-friendly and economic nature. These solar modules are protected by thermoplastic materials acting as encapsulates for photovoltaic cells. Due to its positioning i.e. facing direct sunlight, it gets exposed to extreme heat and temperature. This type of prolong exposure can damage the encapsulant if it’s composed of a poor quality polymer. Hence, testing the flow properties of the material is required by using an efficient Melt flow index tester.
What role does the MFI tester play in assuring quality in solar cell encapsulant?
To ensure the safety and quality of solar panels, it is important to provide an efficient thermoplastic encapsulant for the modules. The polymer used in constructing the encapsulate must deliver high resistance to heat at various temperature range before the material is qualified for use in the field. These type of plastics tends to experience phase transition and visco-elastic flow at a higher temperature, opening the gate for a number of reliability and safety issues.
The flow properties of such polymer must be analysed to evaluate the peak point at which the polymer starts melting. The melt flow rate or MFR is inversely proportional to the zero-shear viscosity. Therefore, it is vital for manufacturers to conduct the MFI test using an accurate testing instrument.
Presto’s Melt flow index tester is utilized for computing the flow characteristics of the molten plastic material. The melt flow index value of thermoplastic products is defined as the flow rate of plastic in grams per ten minutes of time.
t comes out in the form of a flow which is cut down automatically and weighed. The MFI test is conducted under a predetermined condition for the temperature, pressure and the position of the piston within a cylindrical chamber situated inside a heated metallic tube barrel. The testing instrument precisely designed and complies with all the required standards ASTM D 1238-1992, ISO 1133, IS 2267-1972, IS 2530-1963, IS 10810-1984. It is equipped with a microprocessor-based PID temperature controller, along with a temperature range from ambient to 400°C. It offers a resolution of 0.1°C and accuracy of ± 0.1°C. The instrument comes with a digital timer using the testing duration can be set.