Introduction to photovoltaic modules (monocrystalline silicon, polycrystalline silicon, heterojuncti

　　Photovoltaic modules, also known as solar panels, are the most important components in solar power generation systems. A complete photovoltaic module is composed of dozens of solar cells, junction boxes, and frames. Due to the fact that individual solar cells cannot be directly used as power sources, in order to be used as power sources, several individual cells must be connected in series, parallel, and tightly packaged into components.

　　The principle of solar power generation is that sunlight shines on the semiconductor p-n junction of photovoltaic cells, forming new hole electron pairs. Under the action of the p-n junction electric field, holes flow from the p-n region to the n region, and electrons flow from the n region to the p region. After connecting the circuit, current is formed. Its function is to convert solar energy into electrical energy and send it to a battery for storage, or to drive the load to work.

　　Three solar cell panel technologies

　　1. Crystal silicon solar cell technology differs from monocrystalline silicon and polycrystalline silicon. The advantage is that the photoelectric conversion rate is high, with a conversion rate of over 21%. The disadvantage is that the crystal silicon solar cell technology is currently the mainstream technology in the market, which is more expensive.

　　2. Thin film solar cell technology has the advantages of low material consumption and low price. The major disadvantage is that the photoelectric conversion rate is only half of that of crystalline silicon, but the conversion efficiency is only 6% -10%, so the market share has always been very low.

　　3. The advantage of new solar cell technology is high conversion rate and low cost. Perovskite photovoltaic cells are expected to be a new type of solar cell product with the fastest mass production speed. The theoretical efficiency limit of single junction perovskite cells can reach 33%, higher than crystalline silicon cells and thin film cells. However, the biggest drawback of perovskite photovoltaic cells is that their efficiency decay is relatively severe, and they will not be used on a large scale until the efficiency decay technology is solved.

　　Polycrystalline silicon photovoltaic modules and monocrystalline silicon solar modules

　　1. Polycrystalline silicon photovoltaic modules: Photovoltaic modules processed using polycrystalline silicon wafers. Polycrystalline silicon is made from polycrystalline silicon block materials using the ingot casting process (square silicon ingots).

　　2. Single crystal silicon photovoltaic modules: Photovoltaic modules processed using single crystal silicon wafers. Single crystal silicon is produced using polycrystalline silicon block materials using a rod pulling process (circular silicon rods).

　　P-type and N-type photovoltaic modules

　　1. P-type photovoltaic module: A photovoltaic module assembled using P-type solar cells. P-type solar cells are silicon wafers that infiltrate the trivalent element "boron" during the doping process of the cells, and "gallium" can also be added. The conversion rate of photovoltaic modules for P-type batteries has been mass-produced in 2023, ranging from approximately 21.1% to 21.5%.

　　2. N-type photovoltaic module: A photovoltaic module assembled using N-type solar cells. N-type solar cells are silicon wafers that infiltrate the pentavalent element "phosphorus" during the doping process of the cells, and "arsenic" can also be added. The conversion rate of photovoltaic modules produced in 2023 for N-type batteries is approximately 22.1% to 22.5%.

　　Types of photovoltaic module structure processes

　　1. Half piece structure process: Cut one battery cell into two pieces and then assemble them into photovoltaic modules.

　　2. Laminated tile structure process: Cut a battery cell into five to six long strip small pieces, and then use conductive adhesive to overlap the edges of multiple small battery cells to assemble photovoltaic modules.

　　3. Flexible component technology: Flexible components, also known as lightweight components, can be bent and are particularly suitable for installation on curved roofs. One solution is to replace glass panels with flexible panels based on the laminated tile photovoltaic module technology, and the other is to use thin film cells to make flexible photovoltaic modules.

　　Classification of solar cell panel dimensions

　　(1) Introduction to 182 size and 210 size battery cells

　　1. Manufacturer of 182 photovoltaic module lineup: refers to photovoltaic modules with a single cell size of 182 (182mm * 182mm).

　　2. Manufacturer of 210 photovoltaic module lineup: refers to photovoltaic modules with a single cell size of 210 (210mm * 210mm).

　　(2) Introduction to Dimensions and Cells of Rectangular Photovoltaic Modules

　　1. Rectangular photovoltaic module size: On July 7, 2023, 9 domestic photovoltaic module manufacturers reached an agreement to unify the size of rectangular photovoltaic modules to 2382mm * 1134mm.

　　2. Size of rectangular solar cells: On August 8, 2023, six domestic photovoltaic module manufacturers reached an agreement to unify the size of rectangular solar cells to 182.2mm * 191.6mm.

　　Comparison of Technology Routes for P-type Photovoltaic Modules and N-type Photovoltaic Modules

　　(1) P-type battery cell technology route

　　1. BSF technology, also known as aluminum back field battery and aluminum back field passivation technology, has a conversion efficiency of less than 20%. In 2015, it was the mainstream battery technology in the photovoltaic industry and occupied 90% of the market. Due to its low conversion rate, it is now basically phased out.

　　2. PERC technology refers to emitter passivation and back contact technology. The conversion efficiency is about 23%. Currently, mainstream technology has the highest market share, and most P-type photovoltaic modules use PERC technology, with an actual conversion rate of over 21%. In 2020, the proportion of PERC batteries in the global market exceeded 85%, and currently it is mainly double-sided PERC.

　　(2) N-type battery cell technology route

　　1. The IBC full back electrode contact battery has steadily improved its conversion efficiency year by year, with an average conversion efficiency of 24.5% in mass production and a theoretical upper limit of 26.2%.

　　2. HJT heterojunction battery, an intrinsic thin film heterojunction battery technology, is based on crystalline silicon solar cells as the substrate, and then superimposed with thin film solar technology. The main classification still belongs to the N-type module technology route. There are two types of heterojunction batteries, HJT and HIT, with an average conversion efficiency of 24.73% in mass production and a theoretical upper limit of 27.5%.

　　3. TNC passivation contact battery, currently the mass production conversion efficiency of TNC battery has exceeded 25.1%

　　4. TOPCon oxide layer passivation contact battery technology has a maximum efficiency of over 25% in mass production, with a theoretical conversion efficiency limit of 28.7%.

　　(3) Who has more development prospects for P-type and N-type photovoltaic modules

　　1. The theoretical ultimate efficiency of N-type TOPCon batteries is 28.7%, and the conversion rate of mass-produced N-type photovoltaic modules in the market is around 22.1% to 22.5%. There is still significant room for improvement in subsequent technologies.

　　2. The theoretical ultimate efficiency of P-type PERC batteries is 24.5%, and the conversion rate of mass-produced P-type photovoltaic modules is currently around 21.1% to 21.5%. The technological development space is approaching the bottleneck, and there is little room for further technological improvement.

　　3. According to the latest technological trends of various battery cell manufacturers, the P-type mainly focuses on PERC technology, while the N-type has four or five types of battery cell technology in progress. Although the current production of N-type photovoltaic modules is low and the price is high, in the long run, the market share of N-type photovoltaic modules will exceed that of P-type photovoltaic modules. It is expected that N-type photovoltaic modules will become mainstream photovoltaic module products after 2025.

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