Analysis of Technical Difficulty of Concentrating Photovoltaic Power Generation System

Because of the low density of solar energy, the average intensity of the sun's light reaching the ground is 1 kilowatt/square meter; the conversion rate of monocrystalline silicon can reach 23%, polycrystalline can reach 16%, and the thin film can only reach 8%. The gallium arsenide cell sheet with the highest conversion efficiency can reach 35% or more, but the overall conversion efficiency of a solar power system made with gallium arsenide is only about 25%.

Therefore, in order to reduce the price of solar power generation systems, it is a good solution to increase the sunlight intensity. To increase the light intensity, it is necessary to use a convex lens or a Fresnel lens or a reflector to increase the light. This can greatly reduce silicon and arsenic. The use of helium to reduce the price of solar power systems; this is the origin of CPV (concentrating photovoltaic power generation system).

Second, the technical difficulties of the CPV system

The principle of CPV solar power generation system is relatively simple. Why is it that there are few companies in the world that have made particularly stable and cheap power generation systems! In principle, in the CPV field, the higher the convergence factor, the cheaper the cost but the way to use the spotlight. The following questions will appear.

1, so that single crystal silicon high magnification light

Although gallium arsenide can withstand 1,000 times the light intensity, now gallium arsenide is expensive, and arsenic in gallium arsenide is highly toxic, making it impossible to drastically reduce manufacturing costs. In addition, the international environment is the theme of environmental protection. It can't be used in large quantities at the same time. In the end, it can only be monocrystalline silicon; however, monocrystalline silicon can only withstand light intensity of 3 to 5 times. Concentrating 3 to 5 times in CPV field can hardly reduce costs. A significant reduction in costs must be around 10. In order to achieve a 10-fold concentration, special monocrystalline silicon must be used.

2, heat dissipation:

Ordinary silicon led/''target=''_blank''>Photonics panels can reach 75 degrees Celsius in summer at noon, and ordinary silicon panels will blistering at twice the intensity of sunlight in a long time. 5 times of sunlight intensity will blistering in 10 minutes, and in 10 times of sunlight intensity, it will bubble for 5 minutes. After bubbling, solar cells will be oxidized and will be greatly reduced in a short time. Efficiency, in addition to the uneven heating after bubbling, often burst the battery, so that the system is completely unavailable.

If solar panels use aluminum or copper heat sinks to dissipate heat naturally, they require a large number of heat sinks, which are particularly expensive, and are even more expensive than silicon wafers. If forced air cooling is used, a large amount of electrical energy must be used, which is not worth the loss. , And the fan's life and reliability is not high, in order to achieve high reliability must have error checking and redundant settings, this will increase the cost several times, if the fan is broken at noon in the summer, the entire silicon photovoltaic panel may Was completely burned. If water cooling is used in addition to electricity, the cost is not cheap. Water cooling requires more pumps and more connection points. It also requires pumps. The fault point is bound to be more, and the reliability is worse than air cooling. Of course, the efficiency of water cooling is higher than that of air cooling. However, it is not available in solar systems where the failure rate determines a one-vote veto system.

3, reflectors:

Ordinary mirrors and plastic reflectors have different coefficients of thermal expansion and shrinkage between the reflective layer and the skeleton layer (such as glass). In the outdoor 2 to 4 years, the reflective surface will fall off. It may not be used in the desert in high temperature and poor conditions for several months. And the rate of reflection will slowly decline.

In addition, thin aluminum plates with high reflectivity are also used at home and abroad, but such aluminum plates cannot withstand hail and cannot be scrubbed. If scrubbing causes permanent damage, this aluminum plate has a service life of about 8 years, and the light reflectance decreases year by year, 8 years. Basically only 40% of the light reflectance, far from the requirements of the solar system for 25 years; aluminum plate has a protective film, but the protective film is expensive, not to prevent hail, can not solve all the problems. In addition, in order to reduce the cost of aluminum plates are generally about 0.3 mm, so that processing is particularly difficult, and processing costs are particularly high.

4, tracker:

Photovoltaic cells only work at the focal point of the condenser, because the earth is spinning every moment, so tracking devices must be used to ensure that the photovoltaic cells are in the focus of the condenser; the tracker is one of the main systems of the CPV system. Without a tracker system, it can't run. In addition to ensuring that the system can operate, the tracker can generate an average of 30-40% more electricity than a system without tracking. However, the tracker is a mechanical structure. After many years of operation, it will fail and there will be wear and tear. If the tracker fails, the system cannot operate (there is no power supply). If there is wear, the tracking accuracy will be reduced because of the tracking of the CPV system. Accuracy is required. If the accuracy is reduced, a power generation system cannot operate normally.

Third, the solution

In order to solve the problems of the CPV solution system and master the core technology of the CPV system, General Manager Chen Pingjian of Beijing Anxin Hi-Tech Co., Ltd. led his R&D team from March 2008 to invest millions of funds after more than two years of research. After numerous unsuccessful failures, they finally successfully solved the core technology of concentrating 10 times of monocrystalline silicon, and have obtained or are applying for more than 8 patents.

1, so that single crystal silicon high magnification light

After several improvements, we have finally manufactured a single-crystal silicon photovoltaic cell that can withstand 15 times the light intensity, and it is 15% more than the power of the same kind of cell, far exceeding the world's similar products.

2, heat dissipation:

Into dozens of designs, on 10 trials and modifications, finally designed a unique set of cheap radiators, radiators do not require any power, no moving parts, very stable; at an external temperature of 45 degrees, 13 In the case of multiple focusing light, the temperature of the photovoltaic cell can be guaranteed within the specified range. Unpowered, non-moving parts mean maintenance-free, high stability, and will not change performance over time. It is the radiator with the lowest heat/price ratio in the same product.

3, reflectors:

Reflector plate design and production is still relatively smooth, after more than six months of thinking about a successful production, the reflector's light rate is about 77%, the service life will not be less than 25 years, the reflective rate will not be reduced year by year, can It is subjected to hail and can be scrubbed at a price of about 200 yuan per square meter; in addition we have designed a unique processing method that can be processed in a particularly simple manner. Completely solve all the problems of other reflectors.

4, tracker:

After 10 improvements, we have designed a full-motion tracker, that is, the whole is on a big plate, and the east-west rotation is the overall rotation. North-south couplings are also uniformly pitched, greatly providing the stability of the system. Reduced cost and reduced wind resistance. In addition, a special bushing was designed. The water is not afraid of sand. The service life is 100,000 times (the total life span of our entire system is 18,000 times). In addition, the intelligent control system can have In the case of cloud obstruction, the concentrator can always be aimed at the sun as long as the system can generate electricity as soon as the sun comes out, completely solving the shortcomings of existing trackers.

Fourth, the system price

Since our CPV system solves almost all problems, the cost has been greatly reduced compared to existing solar power generation systems. The 500-kilowatt system can achieve 0.8 yuan/kWh; 1 megawatt can achieve 0.7 yuan/kWh; 2 megawatts can achieve 0.6 yuan/kWh; 10 megawatts can be 0.5 yuan/kWh; The Energy Bureau has determined that only solar power can reach a subsidy of 0.8 yuan/kWh, and it can be achieved using our CPV system.