Testing and classification of solar cell modules

Component test

The purpose of the test is to calibrate the output power of the battery, test its output characteristics, and determine the quality level of the components. The content of solar cell module parameter measurement should include insulation resistance, insulation strength, working temperature, reflectivity, and thermomechanical stress, in addition to some commonly used parameters that are the same as those of single solar cells. Insulation resistance measurement is to measure the insulation resistance between the output terminal of the component and the metal substrate or frame. Do safety inspections before measurement, including the square array that has been installed and used. First, check the ground potential, electrostatic effect, and whether the metal substrate frame, support, etc. are well grounded. An ordinary megohmmeter can be used to measure the insulation resistance, but a megohmmeter whose voltage level is roughly equivalent to the open circuit voltage of the square matrix to be tested should be selected. When measuring the insulation resistance, the relative humidity of the atmosphere should not exceed 75%. Insulation strength is the ability of the insulation itself to withstand voltage. When the voltage applied to the insulation exceeds a certain critical value, the insulation will be damaged and lose its insulation function. Generally, the dielectric strength of power equipment is expressed by breakdown voltage; and the dielectric strength of insulating materials is expressed by average breakdown electric field strength, referred to as breakdown field strength. The breakdown field strength refers to the voltage at which breakdown occurs divided by the distance between the two electrodes to which the voltage is applied under the specified test conditions.

In both the indoor test and the outdoor test, the requirements for the shape, size, and size of the reference component are inconsistent. In the case of indoor testing, the structure, material, shape, size, etc. of the reference component are required to be the same as the component under test as much as possible. When measuring outdoors under sunlight, the above requirements can be slightly relaxed, that is, reference components with smaller dimensions and not exactly the same shape can be used. In the measurement of module parameters, it is better to use a reference module to calibrate the irradiance than to directly use a standard solar cell to calibrate the irradiance.

The ground solar cell module operates in the outdoor environment for many years. It must be able to repeatedly withstand various harsh climatic conditions and other changeable environmental conditions, and ensure that its electrical performance does not deteriorate seriously within a fairly long rated life (usually more than 15 years). Before and after each project, it is necessary to observe and check whether there are any abnormalities in the appearance of the components, and whether the maximum output power has dropped by more than 5%. Any abnormal appearance or a drop of more than 5% of the maximum output power is considered unqualified, which is a common requirement of all tests.

High-voltage testing refers to applying a certain voltage between the component frame and the electrode leads to test the voltage resistance and insulation strength of the component to ensure that the component is not damaged under harsh natural conditions (such as lightning strikes, etc.).

Vibration and shock test: The purpose of vibration and shock test is to assess its ability to withstand transportation. The vibration time is 20min in the normal direction and 20min in the tangential direction, and the number of shocks is 3 times in the normal direction and 3 times in the tangential direction.

Hail test: The steel ball used in the simulated hail test weighs about 227g, and the drop height depends on the material of the module cover (tempered glass: height 100cm, high-quality glass: 50cm), and it falls toward the center of the solar cell module.

Salt spray test: The solar cell modules used in the offshore environment should undergo this test. After storing in the mist of 5% sodium chloride aqueous solution for 96 hours, check the appearance, maximum output power and insulation resistance. More stringent inspections include ground solar radiation test, torsion test, constant humidity and heat storage, low temperature storage and temperature alternating test, etc.

wrap up and store

The solar cell modules can be packaged and put into storage after they are qualified.

Classification of solar cell modules

With the development of amorphous silicon solar cells, the same super-gloss packaging method as crystalline silicon solar cells is also being studied. The integrated solar cell substrate glass is directly used as the protective plate of the light-receiving surface, and the connection of each unit cell does not use wires, so the assembly process of the module can be particularly simple. According to the purpose and scale of use, solar cells are divided into various types of modules:

① Components used in electronic products. In order to drive electronic products such as calculators, watches, radios, TVs, chargers, etc., voltages of 1.5V to tens of volts are generally required. The voltage generated by a single solar cell is less than 1V, so to drive these electronic products, multiple solar cell components must be connected in series to achieve the required voltage.

②Condensing type components. The solar cell power generation system works under the focused sunlight, and it is divided into two types: lens type and mirror type. The large-area convex lens necessary for condensing light uses a lens, which connects the curved surfaces of the divided convex lens together. There are two types of reflective type. One is to use a parabolic mirror with solar cells on the focal point, and the other is to place solar cells on the bottom and reflectors on the side. In addition to monocrystalline silicon solar cells, solar cells often use gallium arsenide solar cells with higher conversion efficiency. In addition, there are fluorescent concentrating panel solar cells, which convert the absorbed solar cell light into fluorescence through the fluorescent panel, and the fluorescence propagates in the fluorescent panel, and finally is collected at the end where the solar cell is placed.

③ Hybrid components. The solar-thermal hybrid module is a device for more effective use of solar energy, allowing solar energy to generate electricity and heat. Such hybrid components include concentrating-type light-heat hybrid components and concentrator-type light-heat hybrid components, and so on.

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