IEC 62787-2021 pdf download.Concentrator photovoltaic (CPV) solar cells and cell on carrier (CoC) assemblies – Qualification (IEC 62787:2021).
Firstly, the manufacturer shall supply the minimum threshold voltage of the device. A detailed test procedure for measuring ESD damage thresholds of cells and packages is given in IEC 61 000-4-2, which also provides instructions for verifying the ESD pulse waveform. In determining a device’s ESD threshold, pulses of a particular voltage are applied to the terminals, and then selected parametric measurements are performed. If the parametric measurements do not indicate that the device has failed, then the voltage is increased and the process is repeated. While significant information could be obtained using only voltages up to (or slightly above) the device’s minimum specified threshold (which preferably would be at least 500 V), the voltage should continue to be increased until failure occurs, namely a voltage loss >1 0 % in the dark I-V curve at the current point corresponding to the operation photocurrent at the specified maximum concentration. All measurements will be recorded in the final qualification report.
11 .2.4 Requirements All samples are required to pass the test for the declared minimum threshold voltage. The pass criterion is that device shall exhibit a voltage loss <1 0 % in the dark I-V at the current point corresponding to the operation photocurrent at the specified maximum concentration.
11 .3 Front and back metal adhesion
11 .3.1 Purpose This test is performed to verify the durability of the contacts of the bare solar cell after humidity test consisting of 24 h in a climatic chamber at 95 °C / 90 % RH (pure water and no condensation).
11 .3.2 Procedure The samples shall be tested by applying an adhesive tape which shall be clear in colour with an adhesive strength on steel of at least 0,28 N/mm to both, front and rear surfaces of the solar cell. The tape shall be pressed to transparency and then pulled away with a pull direction of < 45°. The tape is then placed on the form sheet. Additional details can be found in ECSS-E- ST-20-08C Rev.
11.3.3 Requirements No delaminated parts on tape. All requirements of the visual inspection shall be fulfilled.
11 .4 High-temperature storage
11 .4.1 Purpose The main purpose of this test is to determine whether bare solar cells and CoCs can withstand the high temperatures encountered during transportation and storage within their packaging. Thus, the devices do not operate during these tests, but appropriate functionality measurements need to be made before and after the tests. A relatively long-term test (i.e., 1 000 h at +80 °C) is specified for high-temperature storage. The reason for this is that in some cases this test has been found to stimulate failure modes in much the same manner as a high-temperature operations test.
11 .4.2 Procedure The basic procedure for this test is to soak the sample set in an oven or climatic chamber at 80 °C for 1 000 h. The relative humidity inside the oven or chamber should not exceed 40 %. This test follows the IEC 60749-6 but customized to a temperature of 80 °C. The product shall be in its shipping packaging. Visual inspections and performance tests pre and post stress are required.IEC 62787 pdf download.