January 09, 2019 Source: Photovoltaic headlines

After more than ten years of development in the photovoltaic industry, battery fabrication and component packaging technology have entered a new stage of development, from mortar cutting to diamond wire cutting, from polycrystalline to single crystal, from Al-BSF to PERC and from single crystal. Multi-faceted battery and other changes. After PERC, various new technologies such as shingles, half-chips, multi-main grids, double-glass, heterojunctions, and ingot single crystals are blooming everywhere, indicating the bright future prospects of the photovoltaic industry.

Experts who study the roadmap for photovoltaic technology believe that the most advanced GW-class battery processing technology will affect the gradual improvement of battery performance in the next 12-18 months, and the next 3-5 years is expected to trigger the next important turning point. In the market, mainstream PV products are the lowest cost products. In the photovoltaic industry, the overall market size (depending on battery production) and the company's ability to finance capacity expansion or upgrade technology are the two most important factors driving advances in photovoltaic technology.

So, what are the emerging technologies in terms of capacity and market demand? What is the performance improvement space, market capacity and capacity in the next few years? Will it trigger a major new shift in the industry? The international energy network/photovoltaic headline is now closely combined with relevant industry research reports and data, so that the masters can understand the performance level and capacity profile of photovoltaic technology in the current and future years, which will help the development prospects of the industry to be better. understanding.

Tile technology

One of the core technologies of the technology is the unique cell connection technology, which replaces the solder ribbon in the traditional technology and improves the connection between the cells. Under the same area of the shingle structure, more than 6% of the cells of the conventional component can be placed, thereby improving the conversion efficiency.

The shingles are compatible with PERC, half-piece, double-sided, etc., and can be added 15-25W. At present, the PERC is stacked, which can be changed from a conventional 305 watt perc component to a 320 W tiling component. In 2019, it can also be changed from a 310 W conventional PERC to a 320-325 W tiling component. In this case, the price is The premium will be relatively good compared to the profit of the product.

At present, the conversion efficiency of the Zhonghuan shingle components has reached 19.4%, exceeding the requirements of the front runners and super front runners.

In 2017, Oriental Ring, a joint venture between Dongfang Electric, Zhonghuan and SunPower, invested 5 billion yuan to build 21 production lines for shingle components with a planned production capacity of 5GW. Overseas manufacturers include Sunpower and Sailaver, Artes and so on.

The existing capacity of the tile assembly is 3GW, and the shipment in 1018 is 1GW. The largest market is China, and the mainland market accounts for half. Overseas markets are mainly exported to Australia, and others are also available. Expected 3.5 GW in 2019; 2020 will usher in a concentrated outbreak of tiling technology.

From the perspective of the stacking of ships in 2018, most of them are mainly single crystal perc, and then a small amount is a polycrystalline tile assembly. If you analyze it from the size, the main thing is that the Oriental Ring and Sunpower are 72-piece versions, and most of the other manufacturers are 60-piece versions.

Double-sided component

Double-sided components, as the name implies, are components that can generate electricity both on the front and back. And it can be superimposed with many technologies such as PERC, half-chip, and tile, and the contribution of power cost reduction can reach up to 18%. The biggest advantage of the double-sided component is the “increased power generation per watt” under the same conditions.

Double-sided double-glass battery pack technology is simple in technology, low in mass production, power generation gain can reach 5%~30%, and the cost is basically no increase. The ability to reduce the cost is the strongest in high-efficiency component technology, and no other technology is used. In the case of the system, the increase of 5%~30% of the power generation capacity of the double-sided power generation technology can reduce the cost of electricity to 0.02~0.1 yuan kWh, and the lowest to 0.438 yuan kWh, which is 3.8%~18.5%.
There are 40 photovoltaic companies in the world producing double-sided components. The domestic production enterprises include 17 companies such as Jingao, Jingke, Yijing, Tianhe, Longji and Dongfang Risheng. In 2018, the global double-sided component planning capacity exceeds 15GW (if the manufacturer starts production in the fourth quarter, the actual production capacity is about 3.75GW). It is estimated that the planned capacity of double-sided components in 2019 will reach 25.74GW, which is the growth year for double-sided components.

In the bidding for 38 projects of the eight major bases, the bidding enterprises applied for double-sided technology for 54 times, and the double-sided technology won the bid of 2.58GW, accounting for 52%. In the third batch of front-runner projects, double-sided technology accounted for 53% of the application of the leader base project; in the technology-led base project, double-sided technology accounted for 66%. The total number of double-sided double-glass components is about 2.6 GW, accounting for 52%.

PERC technology

PERC (Passivated Emitter and Rear Cell), passivated emitter and back cell technology, originally originated in the 1980s, the biggest difference from conventional batteries in the back surface dielectric film passivation, using local metal contact, greatly reducing the The surface recombination speed increases the light reflection of the back surface.

The upgrade of PERC battery production line only needs to increase the back passivation coating and laser grooving on the basis of the existing production line, which can achieve 1% efficiency improvement on P-type single crystal silicon and 0.6 on polysilicon. % efficiency improvement. In 2018, nearly all of the single crystal cells used the PERC process, and the average efficiency of mass production of the cells reached 21.8%. The polysilicon PERC has begun to enter the industrialization stage, and the average mass production of the cell is 20.6%. Future PERC battery components will reach 325-330W. The photoinduced attenuation of PERC more crystalline conventional batteries is 6~10% higher.

A total of 37 PV companies worldwide produce PERC batteries, with 26 domestic companies. In the past two years, the first-tier manufacturers such as Trina, Jingke and Tongwei have flocked to the production capacity of PERC batteries, and Longji has also completed the upgrade to PERC technology.

The gross profit margin of Perc batteries is much higher than that of conventional batteries, with a single-sided perc of 19.5% and a double-sided perc higher than 22%. From the results of the 2017 5GW PV application leader project, the scalar volume of the PERC component reached 3.274GW, accounting for 65%. In the winning PERC battery, the single crystal PERC is about 90%, and the polycrystalline PERC is about 10%. By the end of 2017, the global PERC capacity has reached 30GW; by the end of 2018, the global PERC capacity will reach 80GW or more; by the end of 2018, the market share of PERC batteries will exceed 30%.

Formally due to the simple upgrade process of PERC battery, the photoelectric conversion efficiency is obviously improved, and it will become the mainstream technical route for battery chip manufacturing in the next few years. At the end of 2019, the international PERC battery capacity is expected to exceed 100GW. By 2020, the global PERC capacity is expected to increase to 120GW. The industry predicts that PERC technology will remain in the mainstream in the next 3-5 years.

Half chip technology

Half-chip is the technology of packaging the battery after 1/2-cut. It essentially reduces the internal resistance of a single cell, and can be used to package polycrystalline or package single crystal components. The advantage of half-chip technology is to improve package efficiency. Half-chip components have lower package losses, typically between 0.2% and 0.5%, while conventional components are typically >1.5%. The second is to reduce the temperature rise of the components. The temperature of the half-piece assembly is 2 ° C ~ 4 ° C lower than the conventional components, which can reduce hot spots and cracks. Experimental data shows that the power generation in this part can be increased by more than 1%. The third is to reduce the occlusion loss.

The half-chip technology is applied to the final 60-piece package of ordinary polycrystalline cells, and the overall power is only increased by 5W; while applied to single-crystal perc cells, it can bring 8-10W of power boost. Double-sided + half-chip: power increased by 5~10W, power generation gain 5%~30%, the cost is basically the same, the minimum electricity cost can reach 0.434 yuan / kWh, reduce 0.023~0.104 yuan / kWh, a decrease of 4.3% ~19.3%.

Representative production companies include Dongfang Risheng, Jingao, Jingke, Longji, Artes, Aikang, Yijing Optoelectronics, GCL Integration, REC Solar, Zhengxin Optoelectronics, and Hanwha. Longji shares broke the 360-watt power in the 60-type single-crystal PERC half-chip assembly, setting a new world record. According to PVinfolink data, as of August 2018, the production capacity of half-chip components has exceeded 18GW, of which the operating capacity of Yijing Optoelectronic Half-chip components is more than 800MW, and it is continuing to expand.

In terms of market, in the bidding for 38 projects of the eight major bases, half of the technology won the bid for two projects totaling 200MW. The market share of half-cell batteries will increase from 5% in 2018 to 40% in 2028. It is expected that the tiling will reach a real development after 2020. Prior to this, "PERC + half-chip" will become a transitional technology.

Heterojunction technique

HIT is an abbreviation of HeterojunctionwithIntrinsicThin-layer, which means an intrinsic film heterojunction. The solar cell has a maximum efficiency of 26.3%. The key technology of the heterojunction cell is the ultra-thin intrinsic amorphous silicon layer i-a-Si, which can greatly reduce the surface recombination of crystalline silicon, thereby obtaining a high open circuit voltage (up to 750 mV). HDT (Hetero-junction Double-side Technology) high-efficiency heterojunction battery is a double-sided light-receiving heterojunction solar cell with low production process temperature, high conversion efficiency, low temperature coefficient, double-sided power generation, etc. A highly efficient solar cell with high cost performance and high technical difficulty in chemical products.

Heterojunction cells have a series of advantages such as high energy conversion efficiency, simple low temperature manufacturing process, thin silicon wafer application, low temperature coefficient and low CTM, and double-sided power generation. The first year of the new component can be attenuated by less than 1%. The heterojunction battery has high temperature and high power generation. At noon of the day, the power generation of the HIT battery is 8-10% higher than that of the general crystalline silicon solar cell, and the power generation of the double glass HIT component is more than 20% higher, with higher users. Additional value.

In 2017, domestic HIT batteries have formed a capacity of 1GW, but the output is limited, only 60MW, the average conversion efficiency is 22.7%, the planned production capacity will be 2.5GW in 2018, and the total production capacity will reach 3.5GW. In terms of mass production, of course, Sanyo, Japan, has an existing capacity of 1 GW and a mass production efficiency of 23%. In addition, there are more mature HIT technologies such as Panasonic, Keneka, Sunpreme, Solarcity, Fujian Lanshi, Jinneng, Zhongzhi (Taixing), Shangyu and other enterprises.

The heterojunction technology has a high threshold and high cost, and has not yet reached the stage of mass production. The key to achieving low-cost mass production is localization of equipment, improved yield and productivity, and lower costs for wafers, low-temperature silver paste, TCO targets, and cleaning and texturing chemicals. Therefore, it is the process cost problem that restricts the future development of heterojunction cells. Only when the cost is reduced can the market be gradually occupied.

MBB multi-main gate technology

MBB (Multi-Busbar, MBB) is also called multi-main gate component. It usually refers to the battery adopting more finer main gates. The main gate lines are 10 or more, and more thinner solder ribbons are used for interconnection between the cells. . The development process of MBB component technology is: 3BB→4BB→5BB→reflective solder ribbon→MBB. In 2013, domestic PV companies Linuo Photovoltaic, Zhongli Tenghui, Suntech, Artes, and Hairun Photovoltaic successively launched four main grid batteries; Zhongdian Electric directly introduced five main grid products. In terms of equipment, multi-main grid welding machines have been localized. Domestic equipment companies such as Ningxia Mavericks, Otway, and Wuxi Pilots can achieve multi-main grid welding. It is expected to usher in a larger scale in the second half of this year. Capacity expansion.

The main features of the multi-main grid technology are: it can greatly reduce the consumption of silver paste in the production process of the battery, and at the same time improve the output power of the module, reduce the cost and increase the efficiency, improve the reliability of the crack resistance, and increase the value of the color. Can be compatible with half-chip technology. With the continuous development of production technology and technical equipment in the past two years, MBB components have gradually entered mass production from the laboratory. From the welding process, domestic multi-main grid welding machines adopt traditional welding methods, which tend to mature and process yield. The indicators are close to the regular level. N-type single crystal twelve-gate double-glass assembly, the half-chip component has a higher front-side power improvement of 6.14W than the whole-piece component; and an overall increase of 16.07W compared to the five-grid whole.

In 2017, Zhengxin Photovoltaic, GCL, Jingke, Tianhe, Zhongsheng and other companies have launched 12 main grid products. At present, the domestic multi-main grid has an existing production capacity of about 1.7 GW. Although relatively small capacity is currently available, multi-main gate technology has already taken a place in the technology leader, which will accelerate the multi-main gate technology to a more mature stage, and it is expected that the actual mass production volume will accelerate. According to the prediction of relevant institutions, the three main grids will gradually disappear in the next few years, and the five main grids have become the mainstream today. It is expected that multi-main grid technology will be applied on a large scale in the next two or three years. In this regard, experts said that MBB industrial equipment gradually matured in 2018, which paved the way for MBB mass production. Multi-main grid capacity will increase in 2019, but greater growth may be after 2020.

Double glass technology

As the name suggests, the double-glass photovoltaic module refers to a photovoltaic cell assembly formed by two glass and solar cells, which are formed by a string of wires and connected in parallel to the lead ends. According to the closeness of the combination of photovoltaic modules and buildings, double-glass photovoltaic buildings can be divided into BIPV and BAPV.

The advantages of double-glass PV modules are: ordinary component warranty is 25 years, dual-glass photovoltaic components are 30 years; life cycle is higher, the power generation is 21% higher than ordinary components; glass wear resistance is very good; glass insulation is better than Backboard; low attenuation rate, high fire rating, and almost zero water permeability.

In fact, double-glass components were first used in BIPV. In the BIPV project, PV modules, as part of the building components, in addition to meeting the PV performance requirements, also need to meet the architectural requirements of construction mechanics, fire protection, aesthetics, lighting, and sound insulation. At present, double glass has been widely used in power plant types such as surface floating power stations, fish-light complementary, agricultural light complementary, BIPV, and front-runner projects. With the promotion of double-sided batteries and the demand of the front-runner base, the double-glass components can be expected in the future.

Double glass component technology represents enterprises: China Energy Conservation, Jingao, Tianhe, Longji, Ruiyuan Dingtai, Amarton, Linyang. In 2017, the output of double-glass components will be 2.6GW, which is expected to increase to 13.4GW in 2018. In 2017, domestic double-glass component shipments reached approximately 2GW, and global shipments reached approximately 3GW, accounting for only 3% of global component shipments. Compared with the single-sided battery, the double-glass double-sided component can achieve 8%-30% power generation gain, and the future will inevitably lead to the substitution effect of the double-glass component on the traditional component, and the double-glass component has a huge replacement space. Double-sided double glass is currently the most significant reserve technology for cost-effective improvement. It is expected that its market penetration will increase from 1% in 2017 to 42% in 2021.

Double-glass components have been used in BIPV for more than 10 years. Some experts predict that the double-glass components will still be the main form of BIPV. As their advantages are recognized by the industry, they will also be widely used in BIPV. In the future, double-glass Components may come in many forms, but symmetric structures will become the main form of double-glass components. Ultra-thin double-glass components will be the future direction of development; currently, double-glass components have a longer life, higher power generation, and more Low attenuation rate and lower cost in the future.

Diamond wire technology

There are two main types of cutting of polycrystalline silicon solar wafers: one is mortar cutting, that is, the use of steel wire to drive silicon carbide particles and silicon wafers in the mortar to act, and then cut; the other is diamond wire cutting, that is, electroplating Method The diamond particles are fixed in a nickel-based alloy layer on the surface of the stainless steel, and the wire saw and the diamond particles move together for cutting. Compared with mortar cutting technology, diamond wire saw cutting technology has the advantages of fast cutting rate, small environmental load and easy recovery of cutting sawdust. It is the mainstream technology of current silicon wafer cutting production.

At present, the dimensional accuracy requirements of silicon wafers are getting higher and higher, and gradually progress toward large diameter, small thickness, small incision loss and high quality surface, which leads to the industrial trend of continuous thinning of diamond wires. In recent years, the diamond wire in the industry has been thinned at a rate of 5-10 μm per year, and the demand for 60 μm and finer specifications is strong in the future. At the same time, the bond strength and resistance between diamond abrasive grains, resins, and bus bars are increasing.

Diamond wire cutting increases machine productivity by a factor of 1.5 and reduces the cost of using photovoltaic modules by 10%. At present, the combination technology of "Golden Wire + Black Silicon + PERC" can effectively improve the battery conversion efficiency. In the first half of 2018, diamond wire cutting technology was widely used in the field of photovoltaic crystal silicon cutting.

From a global perspective, since the manufacture and application of diamond wire originated in the United States, Japan and other countries, the main diamond line providers are concentrated in Japan and the United States, including Japan Asahi, Japan Joint Materials (ALMT), and US DMT. . With the start of Chinese companies entering the market in 2014, the market price of products has declined, and global production capacity has gradually concentrated in China. At present, the total installed capacity of domestic diamond wire accounts for about 70% of the world's total, mainly concentrated in Yangling Meichang, Muller New Materials, Tony Electronics and other companies.

In 2018, Dongni Electronics, Muller New Materials, Yangling Meichang, the company's total production capacity of about 22.2 billion meters of electroplating diamond wire capacity and 14.9 billion meters of resin diamond line capacity.

From the market demand of diamond wire, the demand for diamond wire for global silicon wafers is expected to reach 30.9 billion meters in 2018, of which the demand for diamond wire for monocrystalline silicon is about 12.2 billion meters, and the demand for diamond wire for polysilicon is about 18.7 billion meters. The global total demand is 56.7 billion meters. At the end of 2018, the planned total production capacity of 13 diamond line manufacturers will reach 91.9 billion meters, and the diamond line industry will enter the stage of overcapacity.

Ingot single crystal technology

The technical advantages of polycrystalline ingot silicon wafer products are high productivity, low light decay and low package loss; Cz single crystal products have high conversion efficiency, low dislocation density, and can be made by ingot casting process, and monocrystalline silicon produced by ingot casting method. The film combines the technical advantages of both. After superimposing the PERC technology, the efficiency of the cast single crystal module is 19.897%, and the difference in efficiency from the Cz single crystal is at least 0.18%, and the cost is reduced by 20%. Moreover, the optical decay of the ingot single crystal is 0.5% or more lower than that of the Cz single crystal product.

The ingot monocrystalline silicon wafer can also be better compatible with downstream end products. Since there is no cornering, the silicon wafer area is 100% available, which is 2% larger than the Cz single crystal area. High-efficiency ingot monocrystalline modules (60 pieces) can be packaged to 310 watts. Under the same power output condition, the price of the ingot single crystal module is 0.06 yuan/W lower than that of the Cz single crystal, and the cost of the electric power is 0.006 yuan/degree. Further development of cast single crystals faces four process challenges, namely seed crystal cost, single crystal ratio, high dislocation density and utilization. In China, the main companies studied include Jingao, Qihui Sunshine, Changzhou Tianhe, Poly GCL, Anyang Phoenix Photovoltaic, and Jiangxi Saiwei.

In the case that single crystals and polycrystals are severely squeezed by the market, ingot single crystals will stand out as a new favorite of the market because of their multiple technical advantages. From the current market point of view, the development and production of cast single crystals has begun to re-accelerate, at least 20 ingot manufacturers have been or are ready to open the production of cast single crystal, GCL, Jingke, Xuyang Reddy already have medium batch With the supply capacity, LDK, Artes, Rongde and Huan Tai completed the previous technical reserve. In April 2018, GCL-Poly announced the investment of 20GW ingot crystal production line in Qujing, Yunnan.

A number of companies have announced that the casting single crystal efficiency is 0.3-0.5% lower than that of single crystal. For example, the average mass production efficiency of “Xin single crystal” PERC of GCL is 21.3-21.5%; New Saiwei’s “Single Crystal” green water The series, the average efficiency is 21.3%, etc.; and the price of each piece of ingot single crystal is 0.2-0.3 yuan lower than that of single crystal.