As the demand for solar energy continues to grow, the reliability and durability of photovoltaic (PV) modules become increasingly important. The backsheets of PV modules play a critical role in protecting the internal components and ensuring long-term reliability. Therefore, testing the performance of backsheets under different conditions is essential to evaluate their durability and reliability. One such test is the pressure cooker test (PCT), which is an accelerated aging test that evaluates the moisture resistance of backsheets in a short period of time.
What is a Pressure Cooker Test (PCT)? A pressure cooker test is an accelerated aging test that evaluates the moisture resistance of backsheets in a short period of time. The test is conducted by subjecting the backsheets to high-pressure steam at a temperature of 121°C and a relative humidity of 100% for a period of time. The pressure cooker apparatus is designed to simulate the effects of long-term exposure to moisture and high temperatures, which are common in outdoor environments.
The pressure cooker apparatus is an effective equipment to evaluate the durability and reliability of backsheets under extreme conditions. The Wewon’s pressure cooker apparatus can help identify potential failure modes and provide insights into the degradation mechanisms of backsheets. Furthermore, the PCT test can help manufacturers design more reliable and durable backsheets for PV modules.
| Equipment Model | WEW-PCT-410-HP | WEW-PCT- 450-HP | WEW-PCT- 570-MA | WEW-PCT- 710-PA |
| Chamber Capacity（L） | 16 Liters | 24 Liters | 40 Liters | 50 Liters |
| Test Room (mm) | φ230 x 410 | φ260 x 450 | φ300 x 570 | φ300 x 710 |
| Overall Dimensions | W525 x H410 x D595 | W535 x H440 x D655 | W620 x H490 x D765 | W600 x H980 x D450 |
| Power Voltage (V) | 220 Voltage | 230 Voltage | 220 Voltage | 230 Voltage |
| Current[A) / Power[W] | 9A/2026W | 13A/2770W | 14A/3226W | 14A/3000W |
| Equipment Heater (W) | 1400 W | 1800 W | 2300 W | 2300 W |
| Dry Heater (W) | 526 W | 870 W | 826 W | 600 W |
| Water Consumption | 200-450 CC | 280-350 CC | 350-700 CC | 1000-1200 CC |
| Temperature Test | +134℃ ±1℃ | +121℃ ±1℃ | +134℃ ±1℃ | +121℃ ±1℃ |
| Test Dry Time | 0, 15 min | 15, 30 min | 15, 35 min | 30, 40 min |
| Water Tank Capacity | 4200 CC | 4200 CC | 8400 CC | 9500 CC |
| Equipment Weight (Kg) | 44 KGS | 54 KGS | 77 KGS | 84 KGS |
Why is PCT Important for Photovoltaic Modules? The backsheets of PV modules play a critical role in protecting the internal components from moisture and other environmental factors. Therefore, it is essential to evaluate the durability and reliability of backsheets under different conditions. The PCT test is an important tool for evaluating the moisture resistance of backsheets in a short period of time. The PCT test can help identify potential failure modes and provide insights into the degradation mechanisms of backsheets. By understanding the degradation mechanisms, manufacturers can design more reliable and durable backsheets for PV modules. Furthermore, the PCT test can help ensure that backsheets meet the industry standards for long-term reliability and durability.
How is Pressure Cooker Test (PCT) Conducted? The pressure cooker test is conducted by subjecting the backsheets to high-pressure steam at a temperature of 121°C and a relative humidity of 100% for a period of time. The test is typically conducted for 100 hours, although longer test times may be used to simulate more extreme conditions. During the test, the backsheets are placed in a pressure cooker and subjected to the high-pressure steam. After the test, the backsheets are evaluated for changes in appearance, yellowing index, and peeling strength. Peeling strength is measured using parts of the test sample areas, and the yellowing index is measured with a chroma meter according to ASTM E313.
To ensure the durability and dependability of photovoltaic (PV) modules, several non-standard test protocols have been devised. The challenge with these tests lies in replicating the degradation phenomena observed during outdoor exposure, as there are several factors that contribute to degradation, including temperature, humidity, temperature cycles, and UV light. These factors interact with each other, making it difficult to isolate and reproduce the degradation of the PV module’s performance and materials. Studies have shown that a combination of damp heat (DH) and UV irradiation tests can effectively reproduce degradation phenomena.
Additionally, sequential tests that include DH, thermal cycle (TC), humidity freezing (HF), and dynamic mechanical load (DML) tests have been proposed to simulate the failure of PV modules. Sequential tests for backsheets have also been studied to improve correlation with field results, as the reliability of the backsheet may be a crucial challenge for floating PV models. These sequential tests are critical to ensuring the long-term reliability of PV modules.
In addition to non-standard test protocols, extended IEC tests have been developed to ensure the long-term reliability of PV modules. These tests include extended DH tests or extended TC tests. To save time during such extended tests, pressure cooker tests (PCTs) or high accelerated stress tests (HASTs) have been utilized. These tests can quickly assess the durability of PV encapsulants and investigate relevant degradation mechanisms of PV modules by subjecting them to higher relative humidity (100%), water vapor pressure, and temperatures ranging from 105 to 130 ℃. PCTs and HASTs are useful tools for evaluating the long-term reliability of PV modules in a shorter period of time.
Pressure Cooker Tester – Pressure Cooker Test (PCT)