Myth 1: Photovoltaic wafers should be the same size as semiconductor wafers.
The truth: Photovoltaic silicon wafers have nothing to do with the size of semiconductor silicon wafers, but need to be analyzed from the perspective of the entire photovoltaic industry chain.
Analysis: From the perspective of the industry chain, the cost structure of the photovoltaic industry chain and the semiconductor industry chain is different; at the same time, the increase of the semiconductor silicon wafer does not affect the shape of a single chip, so it does not affect the back-end packaging and application, while the photovoltaic cell If it becomes larger, it has a great impact on the design of photovoltaic modules and power plants.
Myth 2: The bigger the component size, the better. 600W is better than 500W components, and 700W and 800W components will appear next.
The truth: Big for big, bigger is better for LCOE.
Analysis: The purpose of module innovation should be to reduce the cost of photovoltaic power generation. In the case of the same life cycle power generation, the main consideration is whether large modules can reduce the cost of photovoltaic modules or reduce the BOS cost of photovoltaic power plants. On the one hand, oversized components do not bring about the cost reduction of components. On the other hand, it also brings obstacles to the transportation of components, manual installation, and equipment matching at the system end, which is harmful to the cost of electricity. The bigger the better, the bigger the better view is questionable.
Myth 3: Most of the new PERC cell expansions are based on 210 specifications, so 210 will definitely become mainstream in the future.
The truth: Which size becomes the mainstream still depends on the value of the whole industry chain of the product. At present, the 182 size is better.
Analysis: When the size dispute is unclear, battery companies tend to be compatible with large sizes to avoid risks. From another perspective, the newly expanded battery capacity is all compatible with 182 specifications. Who will become the mainstream depends on the value of the entire industry chain of the product.
Myth 4: The larger the wafer size, the lower the component cost.
The truth: Considering the cost of silicon to the component end, the cost of 210 components is higher than that of 182 components.
Analysis: In terms of silicon wafers, the thickening of silicon rods will increase the cost of crystal growth to a certain extent, and the yield of slicing will drop by several percentage points. Overall, the cost of silicon wafers of 210 will increase by 1~2 points/W compared with 182;
The larger silicon wafer is conducive to saving the cost of battery manufacturing, but 210 batteries have higher requirements on manufacturing equipment. Ideally, 210 can only save 1~2 points/W in battery manufacturing cost compared with 182, such as yield, Efficiency has always been different, the cost will be higher;
In terms of components, 210 (half-chip) components have high internal losses due to excessive current, and the component efficiency is about 0.2% lower than that of conventional components, resulting in a cost increase of 1 cent/W. The 55-cell module of 210 reduces the module efficiency by about 0.2% due to the existence of long jumper welding strips, and the cost further rises. In addition, the 60-cell module of 210 has a width of 1.3m. In order to ensure the load capacity of the module, the cost of the frame will increase significantly, and the cost of the module may need to be increased by more than 3 points/W. In order to control the cost of the module, it is necessary to sacrifice the module. load capacity.
Considering the cost of silicon wafer to the component end, the cost of 210 components is higher than that of 182 components. Just looking at battery cost is very one-sided.
Myth 5: The higher the module power, the lower the BOS cost of the photovoltaic power station.
Truth: Compared with 182 components, 210 components are at a disadvantage in BOS cost due to slightly lower efficiency.
Analysis: There is a direct correlation between module efficiency and the BOS cost of photovoltaic power plants. The correlation between module power and BOS cost needs to be analyzed in combination with specific design schemes. The BOS cost savings brought by increasing the power of larger modules at the same efficiency comes from three aspects: the cost savings of large brackets, and the cost savings of high string power on electrical equipment. The saving of the installation cost calculated by the block, of which the saving of the bracket cost is the largest. Specific comparison of 182 and 210 modules: both of them can be used as large brackets for large-scale flat-ground power stations; on the electrical equipment, since the 210 modules correspond to the new string inverters and need to be equipped with 6mm2 cables, it does not bring savings; in terms of installation costs, Even on flat ground, the width of 1.1m and the area of 2.5m2 basically reach the limit of convenient installation by two people. The width of 1.3m and the size of 2.8m2 for the 210 60-cell module assembly will bring obstacles to the installation of the module. Back to module efficiency, 210 modules will be at a disadvantage in BOS cost due to slightly lower efficiency.
Myth 6: The higher the string power, the lower the BOS cost of the photovoltaic power station.
Fact: Increased string power can bring BOS cost savings, but 210 modules and 182 modules are no longer compatible with the original design of electrical equipment (requires 6mm2 cables and high-current inverters), and neither will bring BOS cost savings.
Analysis: Similar to the previous question, this point of view needs to be analyzed in combination with the system design conditions. It is established within a certain range, such as from 156.75 to 158.75 to 166. The size of the component changes is limited, and the size of the bracket carrying the same string does not change much. , inverters are compatible with the original design, so the increase in string power can bring BOS cost savings. For the 182 modules, the module size and weight are larger, and the length of the bracket is also significantly increased, so the positioning is oriented towards large-scale flat power plants, which can further save the BOS cost. Both 210 modules and 182 modules can be matched with large brackets, and the electrical equipment is no longer compatible with the original design (requires 6mm2 cables and high-current inverters), which will not bring BOS cost savings.
Myth 7: 210 modules have low risk of hot spot, and the hot spot temperature is lower than 158.75 and 166 modules.
Fact: The hot spot risk of the 210 module is higher than that of the other modules.
Analysis: The hot spot temperature is indeed related to the current, the number of cells, and the leakage current. The leakage currents of different batteries can be regarded as basically the same. Theoretical analysis of the hot spot energy during laboratory testing: 55cell 210 modules 60cell 210 modules 182 modules 166 modules 156.75 modules, 3 modules after actual measurement (IEC standard test conditions, shading ratio 5%~ 90% of the tests separately) the hot spot temperature also does show a relevant trend. Therefore, the hot spot risk of the 210 module is higher than that of the other modules.
Misunderstanding 8: The junction box matching 210 components has been developed, and the reliability is better than the junction box of the current mainstream components.
TRUTH: The junction box reliability risk for 210 components is significantly increased.
Analysis: 210 double-sided modules require a 30A junction box, because 18A (short-circuit current) × 1.3 (double-sided module coefficient) × 1.25 (bypass diode coefficient) = 29.25A. At present, the 30A junction box is not mature, and the junction box manufacturers consider using double diodes in parallel to achieve 30A. Compared with the junction box of mainstream components, the reliability risk of single diode design increases significantly (the amount of diodes increases, and the two diodes are difficult to be completely consistent) .
Myth 9: 210 components of 60 cells have solved the problem of high container transportation.
Fact: The shipping and packaging solution for 210 components will significantly increase the breakage rate.
Analysis: In order to avoid damage to the components during transportation, the components are placed vertically and packed in wooden boxes. The height of the two wooden boxes is close to the height of a 40-foot high cabinet. When the width of the components is 1.13m, there is only 10cm of forklift loading and unloading allowance left. The width of 210 modules with 60 cells is 1.3m. It claims to be a packaging solution that solves its transportation problems. The modules need to be placed flat in wooden boxes, and the transportation damage rate will inevitably increase significantly.