Although it is in the period of industry adjustment, investment and financing institutions are full of confidence in the photovoltaic industry. Recently, the authoritative domestic securities institutions issued a report from the technical point of view to analyze the technical trend of future photovoltaic modules, and continue to recommend investors to pay attention to photovoltaic.

Bifacial Solar Panels one-sided assembly

The Bifacial Solar Panel module consists of two toughened glass, EVA film and solar cell sheet through laminator high temperature lamination.It includes tempered glass layer, material layer (PVB, PO, EVA or ionic polymer), single crystal or polycrystalline battery pack layer, material layer and tempered glass layer arranged from top to bottom.

All the performances have been improved and the scope of application has been significantly expanded. Because the Bifacial Solar Panels module is pressed by Bifacial Solar Panels, its weatherability and power generation efficiency are better than the traditional module. Especially for the photovoltaic power station, the agricultural greenhouse photovoltaic power station and the photovoltaic power station in the area of high humidity, acid rain or salt fog, the advantages of the Bifacial Solar Panels module are more obvious.

The permeability is zero and the attenuation rate, efficiency and life are optimized simultaneously. The backplane material of single glass module is an organic material. Water vapor can penetrate the backplane and cause the rapid degradation of EVA resin. The decomposition product contains acetic acid. Acetic acid will corrode the silver grid and confluence strip on photovoltaic cells, which will reduce the power generation efficiency of the module year by year.The zero permeability of glass reduces the power loss of the components, improves the power generation efficiency, decreases the attenuation rate by about 0.2 percentage points, and prolongs the life of the components by 5 years to about 30 years.

Good mechanical performance, stable and reliable power generation. The wear resistance, insulation, waterproofing and bearing capacity of glass are better than those of back plate, which can reduce the cracks in parts of components and make the components more stable and reliable in power generation. In addition, the fireproofing level of Bifacial Solar Panels components has been raised from C level to A level, and the fireproofing performance has been significantly improved.

Aluminum-free frame design, effectively solve the PID.The Bifacial Solar Panels module is designed without frame. Without aluminium frame, the electric field leading to the occurrence of PID can not be established, which greatly reduces the possibility of the occurrence of PID attenuation.

Low attenuation, long life and over 20% increase in power generation

Bifacial Solar Panels module can increase power generation by about 3% with lower attenuation rate, but glass instead of backplane penetration.The power loss is caused by the increase of light quantity, so the combined power generation gain of the Bifacial Solar Panels module is about 1%:

Gain: Low attenuation rate contributes 3% to the increase of power generation. Because the attenuation rate of the double-glass module is about 0.2 percentage points lower than that of the single-glass module, the power generation of the double-glass module is 3% higher than that of the traditional module under the same power generation conditions.

Loss:The transmittance increases and the power loss is 2%. Because the EVA film is transparent, there is no leakage between the white backplane reflecting the batteries.As a result, the amount of light that produces photoelectric effect in batteries decreases due to the higher transmittance, and the power loss of the components will be at least 2%.

The use of white EVA as the back packaging material will cause the phenomenon of white EVA overflow to block the battery, which can not solve the power loss problem perfectly.

In addition, the sealing mode of the Bifacial Solar Panel module will affect the function of the water resistor, and the wind pressure tolerance will be affected to some extent after losing the protection of the aluminium frame.

Double-sided battery assemblies

The back of the double-sided battery is printed with aluminium slurry, which is similar to the front of the grid. The back of the battery is covered with aluminium instead of local aluminium.The incident light from the back can enter the battery from the area not covered by the Al layer to realize the double-sided photoelectric conversion function, which is equivalent to increasing the light area of the battery, thereby increasing the power generation.Similar to single-side double-glass module, the back of double-side power generation module is encapsulated with glass or transparent backplane, which optimizes the performance of the module and increases the light transmission on the back.

Compared with single-side double-glass module, the performance and applicability of double-side double-glass module are further strengthened on the basis of zero permeability, excellent mechanical properties, less heat spot damage and low PID probability.

Low working temperature, reduce power loss. Temperature will affect the open-circuit voltage, short-circuit current, peak power and other parameters of solar cell. The peak power loss is 0.35%-0.45% when the temperature rises by 1 C. The back of the double-sided battery is a high-transparent SiNx material. Infrared light can penetrate the battery without being absorbed by the battery. The temperature under normal operation is 5-9 C lower than that of the conventional module, which reduces power loss.

It can be installed vertically and can be used in a wide range. Under the ideal installation inclination, height from the ground and ground reflectivity, the two-sided power generation module can make full use of the reflected light and scattered light in the environment to generate electricity. Therefore, in addition to the traditional installation method, the two-sided power generation module can also be installed vertically, which is suitable for fencing, solar curtain wall, highway sound insulation wall, daylighting agricultural greenhouse and other occasions.

Double-sided power generation, power generation gain 5%~30%.

At the system level, power generation gains range from 5% to 30%. The performance of double-sided power plant system is mainly affected by system design and installation environment. Under the condition of the same nominal peak power and installation location, the output gain of double-sided power generation module is 15%~20%, and the gain can reach 30% with the increase of module height and ground albedo.The gain can even exceed 50% after using oblique uniaxial or tracking equipment.

The efficiency of the back side of the battery is slightly lower than that of the front side, and the light transmission from the back leads to a slight decrease in the front side efficiency. Because the laser hole still needs a grid to guide the photogenerated current, most areas of the back side of the battery are still covered with Al/Ag slurry, and the conductivity of the aluminum grid is not as good as that of the silver grid, so the aluminum grid line is wider and the coverage of the back side is as high as 30%-40%. Therefore, the area of light absorption on the back side is limited. Chemical efficiency(10%-15%) was significantly lower than the positive (20%). At the same time, since the back is made up of all Al layers.The positive efficiency of the battery may decrease by 0.2-0.5% with the change of local coverage and the increase of light transmission.

The generation gain is affected by the reflection background, component orientation, installation angle and ground height: the installation angle of the two-sided generation module can be from 0 to 90 and the bigger the angle is, the more the generation gain of the conventional component will be; the power output will increase significantly after matching with the tracking device such as the tracking axis; the lighter the background color is, the higher the background reflectance is, the more the generation will increase; the higher the height of the two-sided generation module is, the higher the module and the ground The larger the space between the components, the larger the surrounding reflective surface on the back of the components can receive, and the more power generation.

Half cell Solar Panels battery assembly

Halving current reduces working temperature and special series-parallel structure reduces occlusion loss Half-cell Solar Panel battery technology uses laser cutting method to cut the standard battery sheet (156 mm x 156 mm) into two Half-cell Solar Panels batteries (156 x 78 mm) along the direction perpendicular to the main grid of the battery and then weld them in series. In order to be consistent with the electrical parameters of the components consisting of the whole battery, the series and parallel connection of the batteries should be carried out inside the components. One possible way of connection is to connect 20 Half-cell Solar Panels in series with another 20 Half-cell Solar Panels in parallel, then connect the second one in series with the whole, and then connect the third one in series, still using three bypass diodes.

Because the voltage of solar cell is independent of area, and the power is proportional to area, the voltage of Half-cell Solar Panels is unchanged, the power is halved and the current is halved compared with the whole cell.

Considering both the support and the land use rate, it can reduce the loss of power generation caused by occlusion. When conventional photovoltaic modules are installed on photovoltaic power plants for module array arrangement, there are usually two ways: longitudinal arrangement and lateral arrangement. Longitudinal assembly has the advantages of easy installation, high support utilization rate and small area occupation. The disadvantage is that when shadows, dust, water stains, snow and so on in the morning and evening result in occlusion, the power loss of the longitudinal assembly is more than that of the transverse assembly. With its special parallel-series structure, the Half-cell Solar Panels module can improve the support and land use efficiency while reducing the power loss caused by shadow shading.

When the working temperature decreases, the probability of hot spot decreases. Due to the reduction of internal current and internal loss, the working temperature of components and junction boxes decreases, and the probability of hot spot and the risk of damage of the whole components are also greatly reduced. Under the outdoor working condition of the module, the temperature of the Half-cell Solar Panels module itself is about 1.6 C lower than that of the conventional whole-piece module.

Resistance loss reduced by 75% and power increased by 5-10W

Halving the current reduces the resistance loss and increases the power by 5 to 10 W.

The current of the battery slice is reduced to 1/2 of the original current by welding in series, so the resistance loss of the battery slice is reduced to 25% (P = I2R). Thanks to the reduction of loss power, the filling factor and conversion efficiency have been improved, which is 5-10W (+2%~4 z) higher than that of 120 components of the same type.Low working temperature reduces power loss caused by temperature rise. The outdoor working temperature of the Half-cell Solar Panel module is about 1.6 C lower than that of the conventional module. The output power of the Half-cell Solar Panels module is 0.672% higher than that of the whole module under the same conditions according to the calculation of the power temperature coefficient of the module - 0.42%/(-1.88W higher than that of the ordinary module based on the estimation of 280W power).(Source: Guojin Securities)

Related reading: Bifacial Solar Panels,Half-cell Solar Panels