IEC EN 60904-5 Photovoltaic Devices - Part 5: Test for Determination of Equivalent Cell Temperature (ECT) of Photovoltaic (PV) Devices by Open Circuit Voltage Method

EUROLAB, with its state-of-the-art accredited laboratories and expert team, provides precise and fast testing services within the scope of IEC EN 60904-5 testing. IEC EN 60904-5 describes the preferred method for determining the equivalent cell temperature (ECT) of PV devices (cells, modules and arrays of one type of module) in order to compare their thermal properties, determine the NOCT (nominal operating cell).

The main technical changes compared to the previous version are:

• Added method on how to extract input parameters;
• Rewritten method on how to calculate ECT;
• Reworked formulas to comply with IEC 60891.

Two main problems arise when temperature sensors such as thermocouples are used to determine the cell temperature of PV devices under natural or simulated steady-state radiation. First, a significant temperature distribution over the area of ​​the module can be observed. Secondly, as solar cells are generally inaccessible, sensors are attached to the back of the module and therefore the measured temperature is affected by the thermal conductivity of the encapsulant and backing materials. These problems are exacerbated when determining the equivalent cell temperature for in situ measurements of array performance where all cells have slightly different temperatures and the average cell temperature cannot be easily determined.

Equivalent cell temperature (ECT) is the average temperature at the device's electronic junctions (cells, modules, arrays of some type of module) and is equal to the current operating temperature if the entire device is operating uniformly at this junction temperature.

EUROLAB assists manufacturers with IEC EN 60904-5 test compliance. Our test experts, with their professional working mission and principles, provide you, our manufacturers and suppliers, the best service and controlled testing process in our laboratories. Thanks to these services, businesses receive more effective, high-performance and quality testing services and provide safe, fast and uninterrupted service to their customers.