[PV Panel Quality] Lessons Learnt by Panasonic
Performs more than 20 types of unique tests, in addition to conforming to international standards
The Nishikinohama Plant of Panasonic Corp is positioned as the mother plant that controls the production process of the company's solar cell business (Fig. 1 & 2).
Reproduction of harsh natural environments, including light, high temperature, high humidity
Multiple single-story buildings run alongside a large building that accommodates the production line at the Nishikinohama Plant. One of these buildings houses the facilities for accelerated degradation tests of solar panels. I entered the building wearing large sunglasses, having been requested "to wear the glasses to prevent damage to your eyes." Inside the building, the solar panels were being illuminated by huge lights (Fig. 3).
The solar panels were enclosed in a "high temperature/high humidity tank," which reproduces a high temperature/high humidity environment, and were illuminated through a glass panel. The accelerated degradation test that Panasonic calls the "combined light test" is performed under this environment. The facility reproduces severe natural environments.
The international standards for solar panel durability tests are specified by the International Electrotechnical Commission (IEC), and Japanese Industrial Standards (JIS) standards conform to the IEC standards. High temperature/high humidity tests are included in the test items of IEC and JIS, but the "combined light test" where light is irradiated under the high temperature/high humidity environment is unique to Panasonic.
Normal "high temperature/high humidity tanks" incorporate a housing made of steel and are covered with insulation materials, and the internal area is not visible from the outside. For combined light tests, Panasonic constructed custom-made high temperature/high humidity tanks that have glass panels in parts of the housing, aiming to irradiate the panels inside.
"In actual service environments, solar panels are exposed to multiple stresses," said Shingo Okamoto, manager of the Technology Group, Solar Business Unit, Eco Solutions Company of the Panasonic Group. "We improve the reliability by adding our own tests that are stricter than the tests required by IEC and JIS."
"Essential for quality control are design and development with consideration for durability, tests to check reliability and safety, reflection of the test results in design and development and production control to realize the designed quality," he said.
Panasonic performs more than 20 types of tests exclusive to the company, in addition to the tests required by the international standards, and reflects the results in development and design, Okamoto said.
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