As a renewable energy source, solar energy is becoming more and more widely used. There are also more and more companies turning photovoltaic modules into products and pushing them into the to C market. Solar panels, energy storage power supply, and inverters like 2000w inverter or 3000w inverter, can form a distributed small power station that can store and utilize energy. Therefore, as a home solar power system, it is favored by more and more users.

The grade of these solar panels is an important factor affecting their efficiency and performance, so how to judge the solar panel grading? What are the factors that determine the solar panel grading? This article will give you a detailed introduction.



1. What is the solar panel grading?

The solar panel grading can be divided into Grade A, Grade B, Grade C and Grade D. Grade A modules can be divided into two grades, A+ and A-. The same is true for Grade B. The cost difference between different solar panel grading is also very big. So what kind of solar panel is called Class A, and what kind is Class D?

Here we will give you a brief introduction below:

  • Grade A modules: Grade A cells are the highest quality cells that can be used in modules;
  • Grade B modules: Grade B cells are slightly lower than Grade A, and they are complete cells whose components can be downgraded for use;
  • Grade C modules: Grade C cells are seriously poor in appearance and have missing corners. They are only suitable for cutting into small components and supplying them to customers with special needs;
  • Grade D modules: Grade D cells are broken pieces and are supplied to customers with special needs or for special processing.


2. How to tell the grading of solar panels?

Judge the solar panel grading based on the following two points:

① Appearance

  • Look at the surface: Look carefully at the surface of the tempered glass. Products of average quality are relatively rough, and residual silica gel on the surface will reduce the power generation efficiency of the panel.
  • Look at the battery sheet: Check whether there are chips or cracks on the LFP battery sheets. Some non-compliant manufacturers may use broken battery sheets to splice them together. This method has great risks and will affect the safe use of the entire solar panel.
  • Look at the back: Look at the quality under pressure on the back. If there are any unevenness after being pressure-bearing, such as bubbles, wrinkles, etc., it will be regarded as a relatively low-quality product.
  • Look at the border: Check whether it is straight and even. Due to the low barriers to entry in the solar panel industry, many small manufacturers use manual framing methods. If the shape is not strictly rectangular, the firmness will be greatly reduced.
  • Look at the silicone: Check whether the silicone is evenly distributed around the back and whether it has penetrated tightly into the gap between the back panel and the frame.
  • Check the welding: Carefully observe whether there are leaks in the string welding of the battery cells. Also check whether the battery cells are arranged in an orderly manner.
  • Look at the junction box: Finally, check whether the junction box is firm, whether the junction box cover can be firmly and tightly attached to the junction box, and whether the outlet wire lock can rotate freely and can be tightened.


② The way of purchase

Whether you purchase from an authorized dealer of a regular big brand manufacturer, and whether you have a warranty contract, invoice, etc., determines whether you can purchase Grade A components while enjoying after-sales service and long-term warranty service. Now The shelf life of solar panels from regular manufacturers can generally reach more than 20 years.

3. Factors affecting solar panel grading

① Component quality

With the rise of solar power industry, many component factories have joined the market. Some module factories will conduct strict factory inspections during the production process of photovoltaic modules, and classify the modules of solar panel grading into classes A, B, C, and D based on performance and appearance.

Some small component factories simply follow the trend and purchase old battery cells, then process them and resell them. For those who are new to the industry, it will be easy to buy these B- and C-class components, which will break down within a few years. Class A components have excellent performance and a lifespan of at least 25 years. Generally speaking, only Class A components can be circulated openly on the market.

The following are general application scenarios for A, B, and C-level components:

  • Class A components: Mainly used in ground power stations, distributed power stations, household systems, etc., with a lifespan of more than 25 years.
  • Class B components: Mainly used in street lights, off-grid systems, battery vehicles, etc., with a life span of 5 years. Such components are components downgraded from Class A, or produced from Class B materials.
  • Class C components: Mainly used in areas with underdeveloped electricity consumption, such as remote areas, and their service life is unknown.


② Type of solar batteries

The quality of crystalline silicon cells determines the quality of solar panels and solar panel grading. Solar panels are composed of "crystalline silicon batteries", and then the solar panels are formed by packaging technology. Therefore, the type and quality of the "invisible cells" are one of the important determinants of the power generation efficiency and service life of solar panels, also the solar panel grading.

These off grid solar batteries are divided into monocrystalline silicon and polycrystalline silicon by type. As the technology matures, monocrystalline silicon has gradually become mainstream due to its price and efficiency advantages. Because the cells that make up the battery panel are graded, including three solar panel grading: A, B, and C.

  • Grade A battery cells are basically free of defects and may have a few scratches.
  • Grade B battery cells may have defects such as pulp leakage, false printing, and broken grids.
  • Grade C battery cells are mainly recycled cells, which may have problems such as chipping, large areas of false printing, falling strings, and severe contamination.

These solar battery cells are all legal and are used in solar panels as qualified products. The price, power generation effect, and service life of different quality levels will be different, but as qualified products, Grade B and C battery cells are low-priced and can be used by some businesses. This also explains the huge difference in market prices for the same 100-watt solar panels of different solar panel grading.

The silicon material used in solar battery cells is very fragile and easily damaged. After the solar cell panel completes the packaging process, it needs to be fully inspected by EL testing equipment. Solar panels that show cracks and black agglomerations under the EL test are B-class or C-class solar panels, and these black shadows are broken grids and cracks.

Invisible to the naked eye, everyone will think that there is no difference between these solar panels, but in actual use, there will be a huge difference in power generation efficiency and lifespan between the two. Splinters and fragments will not only affect power generation efficiency and usage, but also cause safety hazards due to local cell current short circuits.


③ Solar panel surface packaging material

To consider the light transmittance, you also need to consider its waterproof and other properties. The surface material is divided into tempered glass, textured tempered glass, PET, EFFE, TPT, etc. However, if you calculate one square meter, the usable area will often be larger than the actual coverage area.

So how to choose surface packaging materials? The actual selection of surface materials affectcs solar panel grading, and must be determined based on the usage scenarios and service life of the product. For example:

  • Glass: The service life of glass is relatively long, up to 15-25 years, and its corrosion resistance is relatively high, but its volume and weight are far greater than other products.
  • PET: The life of PET is relatively short, only about 3-5 years, and the price is relatively cheap. However, if you use it at the beach or in a corrosive or foggy place, it can easily lead to problems such as surface degumming.
  • ETFE membrane: Originally a building material, has good light transmittance and weather resistance. It also has an IP67 waterproof rating, is wear-resistant and corrosion-resistant, and has a service life of about 8-10 years.
  • Adhesive: EVA, milky white solid. After high-temperature lamination, it becomes a transparent liquid. Its main function is to bond the surface material of the solar panel, the cells, and the back sheet of the solar panel together. It can ensure the light transmittance of the surface material and facilitate mass production.
  • Backplane material: There are mainly double panels, single panels, epoxy panels, etc. The choice of these materials is determined by the power of your solar panel. The greater the power, the higher the requirements, but if the surface material you use is harder, the requirements for the back material can be lower.


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