Photovoltaic module common three major quality issues

The common quality problems of photovoltaic modules are hot spots, cracking, and power attenuation. Since these quality problems are hidden within the panel, or only after the photovoltaic power plant has been in operation for a period of time, it is difficult to identify the panel when it is accepted into the market, and it needs to be detected by professional equipment.

Hot Spot Formation Causes and Detection Methods

Thermal components of photovoltaic modules refer to components that are exposed to sunlight. Some of the solar cells are blocked and cannot work. As a result, the temperature of the covered parts is much higher than that of the uncovered parts, resulting in burnt dark spots resulting from excessive temperatures. The formation of hot spots of photovoltaic modules is mainly composed of two internal factors, namely the internal resistance and the dark current of the cell itself.

The hot spot endurance test is a test for determining the ability of a solar cell module to withstand the hot spot heating effect. The solar cell module was tested with reasonable time and process to show that the solar cell can be used under the specified conditions for a long period of time. The hot spot detection can be detected with an infrared thermal imager. The infrared thermal imager can use the thermal imaging technology to display the measured target temperature and its distribution with a visible heat map.

Crack formation and detection methods

Hidden cracking refers to the occurrence of small cracks in the cell. The cracking of the cell will accelerate the power attenuation of the cell and affect the normal service life of the component. At the same time, the cracking of the cell will expand under the mechanical load, which may lead to open circuit damage. Hidden cracks can also cause hot-spot effects.

The occurrence of cracking is caused by a combination of factors, such as the uneven force of the components, or the violent shaking during transportation and transportation, which may cause cracking of the battery. PV modules will be tested for EL imaging before leaving the factory. The instrument used is the EL detector. The instrument uses the principle of electroluminescence of crystalline silicon and uses a high-resolution CCD camera to capture the near-infrared image of the module to acquire and determine the defects of the module. The EL detector can detect the presence or absence of cracks, debris, imaginary welding, broken gates, and abnormalities in single-cell batteries with different conversion efficiency.

Power attenuation classification and detection methods

PV module power attenuation refers to the phenomenon that the output power of the module gradually decreases with the increase of the illumination time. Photovoltaic module power attenuation can be roughly classified into three categories: first, the power attenuation of the module due to destructive factors; second, the initial photo-induced attenuation of the module; and third, the degradation of the module. Among them, the first category is the attenuation that can be controlled during the installation of PV modules. For example, strengthening the unloading and transporting of PV modules and controlling the installation quality can reduce the probability of cracking and chipping of the battery cells of the modules. The second and third categories are the process problems that need to be solved in the production of photovoltaic modules. Photovoltaic module power attenuation test can be completed by PV module IV characteristic curve tester.

Photovoltaic module installation quality control

Photovoltaic module installation quality control is the management and control of the entire process of unloading, transporting and installation of photovoltaic modules. Through scientific management, the probability of artificial damage to components is effectively reduced, and the risk of cracking is reduced.

Photovoltaic module unloading vehicle

After the component transport vehicle arrives at the designated unloading site, it is first necessary to confirm whether the quantity of the box is consistent with the manifest, and check that the component outsourcing is equipped with no deformation, collision, damage, scratches, etc., and make relevant records. Before the unloading, the unloading personnel shall have a safe disclosure, and check whether the unloading personnel are in good mental condition, whether the labor insurance products (safety helmets, reflective vests, labor insurance gloves, etc.) are fully equipped, and whether the lifting appliances are working properly;

Check the slings and wire ropes for damage, and use slings and wire ropes that do not meet the requirements or damage. Photovoltaic module unloading pay attention to "slow" and "steady", the components should be placed on a flat, solid ground, is strictly prohibited skew, to prevent dumping, and PV module placement area does not affect road traffic.

PV modules are shipped

Photovoltaic module transport refers to transporting a complete tank photovoltaic module from a concentrated area of ​​photovoltaic modules to a module installation site through a mechanical device or a transport vehicle. Photovoltaic modules need to be controlled within 5km/h to prevent components from chipping due to bumps and bumps. The components should be placed on the flat ground near the PV bracket, and the roads should be clear and the vehicles should be allowed to pass. Photovoltaic modules that have been unpacked at the construction site need to be laid flat on the front, with wooden pallets or battery packs on the bottom. It is forbidden to lay diagonally or float on the panel. It is strictly forbidden to squeeze the lead wires and plugs of the panel and to prohibit the back of the module. Direct exposure to sunlight.

Photovoltaic module installation

Photovoltaic module installation is the largest part of the project, the most problematic link, but also the core part of the quality control of the entire process of unloading, transporting and installation of photovoltaic modules. The unpacking and acceptance of PV modules is an indispensable operation procedure before the installation of the components. The identification of the PV modules identifies whether the product model and parameters meet the contract requirements; through the appearance inspection of the PV modules, the appearance of the components is confirmed to be good, with no obvious damage and scratches. Through the PV module open-circuit voltage, short-circuit current performance tests to determine whether the normal performance of the component is normal, you can ensure that the quality of the product before the installation of components qualified.

In addition, in order to verify the quality of PV modules, it is also an important part of the quality control of components to send samples of several panels of different batches to a professional inspection agency for inspection after the PV modules are delivered to the construction site.

There are two common mounting methods for PV modules, namely bolt mounting and briquetting. Regardless of the type of installation, it is necessary to ensure that the torque value of the component fixing bolts satisfies the product or design document. In addition, the installation method of the briquette needs special attention to the problem of virtual pressure of the edge pressure block and the medium pressure block. Photovoltaic modules should be classified and assembled in accordance with the voltage and current parameters of the components during installation. The allowable deviation of the photovoltaic module installation should meet the requirements in the following table.

The indirect plug-in of PV modules should be firmly connected, and the connection between external cables and plug connectors should be tinned. After PV modules are connected, the open circuit voltage and short-circuit current of the PV array string should be tested. For photovoltaic modules with frame, follow the drawings and The specification requires reliable grounding. During the installation of PV modules, special attention must be paid to the following precautions:

1) PV modules of the same size and same specifications can be connected in series;

2) It is forbidden to install photovoltaic modules under rain, snow or windy weather conditions;

3) It is forbidden to connect the positive and negative fast connectors of the same PV module connection line;

4) The use of photovoltaic module backplane (EVA) will be forbidden after damage occurs;

5) It is forbidden to step on the battery board to avoid damage to components or personal injury;

6) It is strictly forbidden to squeeze or use a sharp object to beat, collide, scratch the photovoltaic module tempered glass;

7) The unpacked battery board at the construction site must be laid flat on the front and the bottom is covered with wooden pallets or battery packs. It is forbidden to stand upright, lay diagonally or hang it open, and it is forbidden to directly expose the back of the module under sunlight;

8) The components should be handled by two people at the same time during handling, and they should be handled with care and light to avoid large shocks, so as not to cause the photovoltaic components to crack;

9) It is forbidden to lift the assembly by pulling the junction box or the connecting cable;

10) When installing the upper panel, it is necessary to pay attention to the battery panel scratches already installed in the handling process;

11) It is forbidden for the installer to use the tool to touch the battery board at will, resulting in scratches;

12) Do not touch the live parts of the PV module string.

13) For components with an open circuit voltage exceeding 50V, and/or components with a maximum system voltage exceeding 50V, there shall be a warning sign that indicates the risk of electric shock.

Active Ingredient:     Quaternary ammonium salt cationic surfactant 
Chemical Name:       Formaldehyde-free Fixing Agent  
Chemical Family:     PolyDADMAC

CAS No.:                   26062-79-3  

1.Formaldehyde-free Fixing Agent 

2.Has no free formaldehyde,no peculiar smell,no irritation to skin, accord to eco request  

[Description]:

        Formaldehyde-free Fixative Color Fixing Agent is belongs to polymerization polyDADMAC, a cationic polymer. It can make up of macromolecular compound with dye, then achieve to improve soaping and rub fastness of fabrics. It can be used for color fixing for dyeing and printing of reactive dyed fabrics as cotton, linen, silk, and direct dyed fabrics.

[Specification]:

              Appearance:  Brownish yellow viscous liquid

              Ionic character:  Cationic

              PH Value:  5-8 (1% aqueous solution)

              Dissolution:  Dissolve in cold water easily.

              Composition: Special polymer compound

[Dilution Method]:

With 4-6 times the water and stir to dissolve dilution.

[Direction for Usage]:(To dilute finished product as an example)

A. Padding Process: 5-20g/L, temperature 40°C-60°C, PH Value:5-8, One-dip-one-nip or Double-dip-double-nip.

B. Dipping process: 1-4% (O.W.F), Room temperature 40°C-60°C, PH Value:5-8, bath ratio:1:8-12,Time: 20-30 min.

[Properties]:

1. Concentrated Formaldehyde-free Fixative Fixing Agent has good color fixing property, can obviously improve the dyeing or printing of fabric soaping, washing fastness and wet rubbing fastness.

2. Can be used for much of the association between dye fixation, anti fading property, does not affect the dyeing or printing of fabric vividness. No effect for the original feel, processing fabric has excellent hydrophilic.

3. Formaldehyde-free Fixative  widely used for dyeing or printing of the direct, active dye fixing finishing, good fixation effect, especially for the red dye and Cuilan dyes, particularly prominent, fixation is better than the general Formaldehyde-free Fixative.

4. The dye PH value for a wide range, acid, alkali resistance, resistance to hard water, high temperature resistance, an environment-friendly products, does not contain formaldehyde.

Fixative (Dye-Fixing Agent)

Fixative,Dye-Fixing Agent,Organic Dye-Fixing Agent,Reactive Dye-Fixing Agent

Shandong Tiancheng Chemical Co., Ltd. , https://www.akdchemical.nl