IEEE1513 Temperature Cycle Test , Humidity Freezing Test and Thermal-humidity Test 1
Among the environmental reliability test requirements of Cells, Receiver, and Module of concentrated solar cells have their own test methods and test conditions in temperature cycle test, humidity freezing test, and thermal-humidity test, and there are also differences in the quality confirmation after the test. Therefore, IEEE1513 has three tests on temperature cycle test, humidity freezing test and thermal-humidity test in the specification, and its differences and test methods are sorted out for everyone's reference.
Reference source: IEEE Std 1513-2001
IEEE1513-5.7 Thermal cycle test IEEE1513-5.7 thermal cycle test
Objective: To determine whether the receiving end can properly withstand the failure caused by the thermal expansion difference between the parts and the joint material, especially the solder joint and package quality. Background: Temperature cycling tests of concentrated solar cells reveal welding fatigue of copper heat sinks and require complete ultrasonic transmission to detect crack growth in the cells (SAND92-0958 [B5]).
Crack propagation is a function of the temperature cycle number, the initial complete solder joint, solder joint type, between the battery and the radiator due to the thermal expansion coefficient and temperature cycle parameters, after the thermal cycle test to check the receiver structure of the packaging and insulation material quality. There are two test plans for the program, tested as follows:
Program A and Program B
Procedure A: Test receiver resistance at thermal stress caused by thermal expansion difference
Procedure B: Temperature cycle before humidity freezing test
Before pretreatment, it is emphasized that the initial defects of the receiving material are caused by actual wet freezing. In order to adapt to different concentrated solar energy designs, temperature cycle tests of program A and Program B can be checked, which are listed in Table 1 and Table 2.
1. These receivers are designed with solar cells directly connected to copper radiators, and the conditions required are listed in the first row table
2. This will ensure that potential failure mechanisms, which may lead to defects occurring during the development process, are discovered. These designs adopt different methods and can use alternative conditions as shown in the table to debond the radiator of the battery.
Table 3 shows that the receiving portion performs a program B temperature cycle prior to the alternative.
Since program B mainly tests other materials on the receiving end, alternatives are offered to all designs
Table 1 - Temperature cycle procedure test for receivers
Program A- Thermal cycle
Option
Maximum temperature
Total number of cycles
Application current
Required design
TCR-A
110℃
250
No
The battery is welded directly to the copper radiator
TCR-B
90℃
500
No
Other design records
TCR-C
90℃
250
I(applied) = Isc
Other design records
Table 2 - Temperature cycle procedure test of the receiver
Procedure B- Temperature cycle before wet freezing test
Option
Maximum temperature
Total number of cycles
Application current
Required design
HFR-A
110℃
100
No
Documentation of all designs
HFR-B
90℃
200
No
Documentation of all designs
HFR-C
90℃
100
I(applied) = Isc
Documentation of all designs
Procedure: The receiving end will be subjected to a temperature cycle between -40 °C and the maximum temperature (following the test procedure in Table 1 and Table 2), the cycle test can be put into a single or two boxes of gas temperature shock test chamber, the liquid shock cycle should not be used, the dwell time is at least 10 minutes, and the high and low temperature should be within the requirement of ±5 °C. The cycle frequency should not be greater than 24 cycles a day and not less than 4 cycles a day, the recommended frequency is 18 times a day.
The number of thermal cycles and the maximum temperature required for the two samples, refer to Table 3 (Procedure B of Figure 1), after which a visual inspection and electrical characteristics test will be carried out (refer to 5.1 and 5.2). These samples will be subjected to a wet freezing test, according to 5.8, and a larger receiver will refer to 4.1.1(this procedure is illustrated in Figure 2).
Background: The purpose of the temperature cycle test is to accelerate the test that will appear in the short term failure mechanism, prior to the detection of concentrating solar hardware failure, therefore, the test includes the possibility of seeing a wide temperature difference beyond the module range, the upper limit of the temperature cycle of 60 ° C is based on the softening temperature of many module acrylic lenses, for other designs, the temperature of the module. The upper limit of the temperature cycle is 90 ° C (see Table 3)
Table 3- List of test conditions for module temperature cycles
Procedure B Temperature cycle pretreatment before wet freezing test
Option
Maximum temperature
Total number of cycles
Application current
Required design
TCM-A
90℃
50
No
Documentation of all designs
TEM-B
60℃
200
No
Plastic lens module design may be required