(Report Producer/Author: Minsheng Securities, Deng Yongkang, Guo Yanchen)
01. Industry trend: P-type is still dominant, and N-type is expected to take over the baton
P-type battery: PERC dominates and is close to the limit of conversion efficiency
Crystalline silicon cell technology is based on silicon wafers as a substrate, and is divided into P-type cells and N-type cells according to the differences of silicon wafers. There is no essential difference in the principle of power generation between the two batteries, and both are based on the PN junction for photogenerated carrier separation. The solar cell that diffuses phosphorus on the P-type semiconductor material to form an n+/p-type structure is a P-type cell; a solar cell that injects boron on the N-type semiconductor material to form a p+/n-type structure is an N-type cell.
The production process of P-type batteries is relatively simple and low cost, mainly BSF batteries and PERC batteries. Before 2015, BSF batteries accounted for 90% of the market; after 2016, PERC batteries took over the baton, and by 2020, PERC batteries accounted for more than 85% of the global market.
PERC (PassivatedEmitterRearCell) - emitter and back-passivation battery technology, different from conventional batteries in the back, PERC batteries use a passivation film to passivate the back, replacing the traditional all-aluminum backfield, enhancing the reflection of light in the silicon-based inner back, reducing the composite rate of the back, so that the efficiency of the battery is increased by 0.5%-1%. In 2020, the average conversion efficiency of single/poly cells produced at scale will reach 22.7% and 19.4%, respectively. P-type mono cells have adopted PERC technology, and the average conversion efficiency has increased by 0.5 percentage points year-on-year.
Due to the theoretical conversion efficiency limit of P-type monocrystalline silicon PERC cells is 24.5%, it is difficult to significantly improve the efficiency of P-type PERC monocrystalline cells; and the light decay phenomenon generated by P-type silicon wafer-based cells has not been completely solved, which makes it difficult for P-type silicon cells to have further development. Compared with traditional P-type monocrystalline cells and P-type polycrystalline cells, N-type batteries have the advantages of high conversion efficiency, high bifacial rate, low temperature coefficient, no light decay, good weak light effect, and longer carrier life.
N-type battery: the advantage is obvious, it is expected to take over the baton
The life of a small number of carriers of N-type silicon wafers is at least one order of magnitude higher than that of P-type silicon wafers, which will greatly improve the open circuit voltage and short-circuit current of the battery, resulting in higher cell conversion efficiency; N-type silicon wafers are mainly incorporated with phosphorus, and boron-oxygen atomic pairs will not be formed in the material (that is, the main reason for photo-induced attenuation of P-type batteries), so the initial photo-induced attenuation of N-type silicon cells and components is almost zero; The temperature coefficient of N-type batteries is low, and the power generation is increased. Every time the temperature of the traditional P-type battery is increased by one degree, the output power is reduced by 0.4% to 0.5%, while the temperature coefficient of the N-type battery is only about half of the former; N-type batteries have good spectral response under weak light conditions, and double-sided batteries achieve "dual-core power generation", and the power generation can be increased by 20% to 30% in a suitable installed environment.
02 TOPCon: Unveiling the curtain on the transformation of battery technology, it is expected to enjoy the technology premium
Process technology
TOPCon (TunnelOxidePassivatedContact) – Oxide layer passivation contact. There is no essential difference between the front and conventional N-type solar cells or N-PERT solar cells, and the core technology of the battery is the passivation contact on the back. The back of the cell is composed of a layer of ultra-thin silicon oxide (1~ 2 nm) and a layer of phosphorus-doped microcrystalline amorphous mixed Si film, which together form a passivation contact structure. The passivation performance is activated by annealing process, during which the crystallinity of the Si film changes, from a microcrystalline amorphous mixed phase to polycrystalline. Annealed at annealing temperature of 850°C, iVoc > 710mV, J0 at 9-13fA/cm2, showing excellent passivation properties of the passivation contact structure.
This structure can block the few sub-hole recombination, increase the battery open circuit voltage and short circuit current. Ultra-thin oxide layer can make multi-son electron tunneling into the polycrystalline silicon layer while blocking the few electron hole composite, ultra-thin silicon oxide and heavily doped silicon film good passivation effect makes the surface of the silicon wafer band bending, thereby forming a field passivation effect, the probability of electron tunnel penetration is greatly increased, the contact resistance drops, improving the open circuit voltage and short circuit current of the battery, thereby improving the cell conversion efficiency.
advantage
Advantage 1: The theoretical conversion efficiency is high and the performance is excellent. TOPCon is a tunnel-through oxide layer passivation contact developed on the basis of the N-type battery process. (TunnelOxidePassivatedContact) technology, which can greatly improve the VOC and conversion efficiency of N-type batteries. According to theoretical calculations, the potential efficiency of passivated contact solar cells (28.7%) is closest to the theoretical limit efficiency of crystalline silicon solar cells (29.43%), and much higher than perC's 24.5%. At present, the mass production efficiency of TOPCon mainstream batteries is about 23.7-23.8%, and some battery manufacturers have announced that they have achieved 24.0%+; many companies, including Jolywood, have achieved laboratory efficiency of more than 25%, and the future prospects are broad.
Advantage two: it is expected to extend the life cycle of the PERC production line and have low marginal investment costs. BOTH TOPCon and PERC are high-temperature processes, and the existing traditional P-type battery equipment process is retained and utilized to the greatest extent, mainly adding LPCVD/PECVD/PVD equipment for polycrystalline silicon/amorphous silicon deposition, boron diffusion and other equipment. The battery technology and production line equipment are more compatible, and TOPCon can be upgraded from the PERC production line without the need for a new production line. If you consider upgrading from the PERC production line, you only need to increase the investment amount of 0.5-100 million yuan / GW, and the marginal investment cost is better than other N-type technology routes. Under the pressure of depreciation of large-scale PERC production line equipment assets, the transformation to TOPCon is conducive to reducing the risk of sunk. The old PERC capacity can be remodeled and expanded to TOPCon, which can adopt the tubular LPCVDn-poly-Si or PECVDn-poly-Si technology route. In the future, it is expected that with the decline of non-silicon costs and the further improvement of yield and efficiency, TOPCon will quickly narrow the cost gap with PERC and become a new generation of mainstream products.
Industrialization Progress – Yield & Economy
Yield rates still need to be improved. TOPCon overall yield is 93-95%; PERC battery yield is between 97-98%.
The reasons for the low yield: 1) There are more processing steps, and the current technical route is not uniform, and multiple technical routes are parallel. 2) The high temperature process leads to warpage, debris and other problems are more prominent, and the uniformity of LP tunneling and oxidation leads to the occurrence of dark films and dirt, which also reduces the yield performance. 3) Card slot printing, etc. appears during the tunneling oxidation process. The above problems are expected to gradually improve with the acceleration of industrialization. (Source: Future Think Tank)
Cost structure: The cost component of TOPCon batteries per watt is mainly silicon wafers, silver paste and depreciation, accounting for 62.5%, 15.8% and 3.7% of the cost respectively.
Silver paste: According to PVInfolink statistics, as of the end of 2021, the non-silicon cost of TOPCon batteries has been able to be lower than RMB0.3/W, compared with the current average RMB0.21-0.23/W of PERC cells, there is still a gap, mainly because the single consumption of silver paste is higher, the front and back of TOPCon use silver paste, M6TOPCon batteries use silver paste about 130mg higher than PERCM6 batteries about 60mg; but now the back can use silver aluminum paste to reduce costs.
Depreciation: At present, the investment in PERC single GW equipment is 120-150 million yuan; TOPCon is about 200-250 million yuan. The main new equipment is LPCVD/PECVD equipment for amorphous silicon deposition and coating equipment. In the future, with the improvement of equipment efficiency, the decline in equipment prices, and the increase in production scale, depreciation costs are expected to decline further.
Industrialization progress - capacity planning
Manufacturers have accelerated THE CAPACITY planning of TOPCon and promoted the industrialization process. In the past two years, domestic enterprises have basically reserved TOPCon transformation space for perC's new production line for subsequent upgrades. The PERC production capacity of many first-line large factories has gradually stopped, and the current expansion plans have also shifted to the construction of N-type technology production lines. Entering the second quarter, the TOPCon production capacity of many manufacturers, including Jinko, has begun to be released, and it is expected to enjoy the technology premium.
Major enterprises: LONGi, Jolywood, Jinko, Trina Solar, Oriental Risheng, etc. Most of them are vertically integrated enterprises, due to the large existing capacity of PERC batteries, since 2019, the new PERC production capacity has basically reserved TOPCon interfaces for subsequent upgrades.
Conversion efficiency: Jolywood is one of the earliest enterprises to lay out TOPCon, and the average conversion efficiency of its TOPCon battery mass production batch is 24.2%, and some products reach 24.5%. TopCon currently announced the highest laboratory conversion efficiency of 25.4% in mid-2021. JinkoSolar is the first company in TOPCon to achieve GW-level shipments, and it is expected that JinkoSolar's single-quarter TOPCon shipments in the second quarter are expected to exceed 1GW.
Capacity planning: With reference to PVInfoLink and Jibang New Energy statistics, by the end of 2022, the industry's TOPCon production capacity is expected to exceed 40GW, and it is expected to reach about 80GW by the end of 2023.
03. HJT: Strong technological breakthrough, clear cost reduction path
HJT (HeterojunctionwithIntrinsicThin-film) – intrinsic thin film heterojunction battery. It has a symmetrical double-sided cell structure with N-type crystalline silicon in the middle. The eigen-amorphous silicon film and the P-type amorphous silicon film are deposited sequentially on the front, thus forming a P-N junction. The eigen-amorphous silicon film and the N-type amorphous silicon film are deposited sequentially on the back side to form a dorsal surface field. In view of the poor conductivity of amorphous silicon, a transparent conductive film (TCO) is deposited on both sides of the cell for conduction, and finally a screen printing technology is used to form a double-sided electrode.
Advantage one: the process flow is short. The HJT battery process mainly includes 4 links: fleece, amorphous silicon deposition, TCO deposition, screen printing; far less than PERC (10) and TOPCON (12-13). Among them, amorphous silicon deposition mainly uses the PECVD method. There are currently two methods of TCO thin film deposition: RPD (reactive plasma deposition) and PVD (physico-chemical vapor deposition). Sumitomo Heavy Industries has patents for RPDs, while PVD technology is mature and there are many manufacturers providing equipment.
Advantage two: high conversion efficiency. This is mainly due to the double passivation of N-type silicon substrates and amorphous silicon to substrate surface defects. At present, the mass production efficiency has generally been more than 24%; the technical route of more than 25% has been very clear, that is, the existing doping is replaced by doped nanocrystalline silicon, doped microcrystalline silicon, doped microcrystalline silicon oxide, and doped microcrystalline silicon carbide on the front and back surfaces; HJT may be improved to more than 30% in the future.
Advantage three: no LID and PID, low attenuation. Since the substrate of HJT batteries is usually N-type monocrystalline silicon, and N-type monocrystalline silicon is phosphorus-doped, there is no boron-oxygen complex, boron-iron complex, etc. in P-type crystalline silicon, so HJT cells are immune to LID effect. The surface of the HJT battery is deposited with A TCO film, no insulating layer, so there is no chance of the surface layer being charged, which structurally avoids piD occurrence. HJT batteries decay by 1-2% in the first year, and then 0.25% per year thereafter, which is much lower than the attenuation of percyc battery-doped gallium blades (2% in the first year, and 0.45% per year thereafter), and therefore the power generation per W of the HJT battery is about 1.9%-2.9% higher than that of double-sided PERC batteries throughout its life cycle.
Industrialization progress - economy
The current high cost is an important factor limiting the large-scale industrialization of HJT technology. 1, HJT and PERC process route is completely different, can not be extended, can only be new production line, and HJT and mainstream PERC production equipment is not compatible, so PECVD and other membrane and vacuum equipment input will bring higher conversion costs to enterprises. 2. HJT battery cost structure: silicon wafer cost, non-silicon materials (silver paste, target materials, gases and chemicals, etc.), equipment depreciation, other manufacturing costs (including labor, power costs), etc. The high cost of HJT batteries is mainly reflected in the slurry, target materials and equipment. 1) Because the conductivity of the low-temperature silver paste required by HJT is relatively weaker, and the welding tension is low, the consumption is relatively large, and the localization rate of low-temperature silver paste is low, making its price currently significantly higher than that of high-temperature silver paste. 2) HJT requires additional deposition of a transparent conductive layer, and targets such as ITO (PVD route) or IWO (RPD route) used are more expensive. 3) HJT equipment investment is high. At present, the investment in HJT equipment is 400 million to 450 million yuan / GW, which is more than twice that of PERC (about 150 million to 200 million yuan / GW).
Cost Reduction Path - Device cost reduction
Before 2019, HJT equipment was mainly provided by foreign brands such as Meyer Burger, YAC, AMAT, and Sumitomo of Japan, and the equipment cost was about 1-2 billion/GW; in 2019, Maiwei, Junshi, Jiejia Weichuang, etc. promoted import substitution, and the equipment cost fell to 5-1 billion/GW; in 2020, the European veteran leader Meyer Borg withdrew from competition; and the cost of HJT equipment fell to 500 million/GW in 20 years. At present, the domestic equipment manufacturers Maiwei, Jiejia, Junshi have the ability to supply HJT equipment; with the localization of HJT equipment, the current investment cost has dropped to 450 million yuan / GW left right, but compared with PERC's 150-200 million yuan / GW and TOPCon's 200 million yuan / GW is still higher, high equipment investment costs not only affect the enthusiasm of early investment, but also mean that the depreciation in the future non-silicon cost is higher, in addition, the current large-scale production of HJT manufacturers is insufficient, The depreciation cost of HJT is at least 0.03 yuan /W higher than PERC.
04. IBC: The potential is large and it is expected to usher in development
IBC (Interdigitated BackContact) – Cross-finger back-contact battery technology. The P/N junction, the substrate and the contact electrode of the emission region are made on the back of the battery in the shape of an interphalange. Core technology: how to prepare a good quality, forked finger-like spaced p-zone and n-region on the back of the battery. By printing a layer of boron-containing fork finger diffusion mask layer on the back of the battery, the boron on the mask layer diffuses into the N-type substrate to form a p+ region, while the area of the unprinted mask layer is formed after phosphorus diffusion to form an n+ region. Pyramidal suedes are prepared on the anterior surface to enhance the absorption of light while forming an anterior surface field (FSF) on the anterior surface. The use of ion implantation technology can obtain p-region and n-region with good uniformity and precise and controllable junction depth, but the high cost has not yet been industrialized. IBC batteries have a complex process, using semiconductor technologies such as masking and lithography many times, and the cost is almost twice that of conventional batteries.
Advantages and disadvantages
Advantages: 1) the front of the battery without gate line occlusion, can eliminate the metal electrode shading current loss, to achieve the maximum utilization of incident photons, compared with the conventional solar cell short-circuit current can be increased by 7% left right; 2) due to the back contact structure, do not have to consider the grid line occlusion problem, can be appropriately widened grid ratio, thereby reducing the series resistance and has a high filling factor; 3) the surface passivation and surface trap light structure can be optimized design, can obtain a lower front surface composite rate and surface reflection, thereby improving Voc and Jsc 4) Beautiful appearance, especially suitable for photovoltaic building integration, with good commercial prospects;
Disadvantages: 1) The process flow is complex, and it is necessary to prepare the P and N regions arranged in a fork finger spaced on the back of the battery, and form metallization contacts and grid lines on top of them, the key processes include diffusion doping, passivation coating, metallization grid line three aspects, the need for multiple masking and lithography technology, in order to prevent leakage, the gap area between the p-area and the n-area also needs to be very precise, and the process research and development capabilities of battery manufacturers are higher. 2) The substrate material requirements are higher, and higher sub-particle life is required: Because the IBC battery belongs to the back junction battery, in order to make the photogenerated carrier as little or no combination as possible before reaching the back p-n junction, a higher oligono diffusion length is required. 3) IBC's complex process steps make its production cost much higher than that of traditional crystal silicon cells; because the conversion efficiency of mainstream PERC cells has reached 23%, TOPCon cells and HJT cells can also reach 24.5%, and the efficiency premium obtained by IBC cells is difficult to cover the increased costs, and the competitiveness is not obvious.
Industrialization progress
UnPowery leads: In 1975, Schwartz and Lambert first proposed the concept of back-contact photovoltaic cells; in 1984, Stanford Professor Swanson developed an IBC-like PointContactCell (PCC) solar cell, which converts 19.7% efficiency under the concentrating system; In 1985, Professor Swanson founded SunPower; in 2004, SunPower's Philippines plant (25MW capacity) mass-produced first-generation IBC batteries with a conversion efficiency of up to 21.5% and a module price of $5-6/W.
SunPower's latest generation of IBC batteries: absorbing the technical advantages of PASSivation contact of TOPCon batteries, retaining the copper electrode process; from the perspective of battery structure, the mass production process has been simplified, and the conversion efficiency has reached more than 25%.
05. Investment Analysis
Photovoltaic cells, after the wave rushes
Technology iteration has always been the key to promoting the development of the photovoltaic industry. The past few years is the rapid expansion stage of PERC battery applications, into 2022, the technical iteration of photovoltaic cells has officially ushered in a new era, TOPCon, HJT, IBC and other cell technologies with higher conversion efficiency will move from the laboratory to the industrial chain, in the process of forming a virtuous cycle of production - scale effect cost reduction - continuous expansion, enterprises that enjoy technology dividends are expected to usher in the dual advantages of market share increase + enjoy technology premium.
Analysis of key companies
LONGi Shares: The integration strategy continues to advance, and R&D and production expansion go hand in hand
Accelerate the expansion of production capacity and consolidate the leading position in the industry. 2021Q1-Q3 company module shipments of about 27GW, of which exports 25-26GW. Module shipments in the third quarter of a single quarter were about 10GW, basically flat month-on-month, of which the export scale was about 9.0GW. Since the company first became a module shipment leader in 2020, the current leading position is stable, with the continuous improvement of the concentration of the module industry, it is expected that in 2022, the company's module production capacity will exceed 80GW, shipments will exceed 60GW, continue to strengthen the leading position; at the same time, the company's silicon wafer and cell production capacity is still expanding, and the integration strategy continues to advance. (Source: Future Think Tank)
Be forward-looking and lay out the next generation of technology. In January 2022, Taizhou Longji Leye annual output of 4GW monocrystalline cell project EIA information disclosure, LONGi plans to transform the original annual output of 2GW mono cell project production line, transformed into 8 HPBC high-efficiency monocrystalline cell production lines, is expected to form an annual output of 4GW of cell production line, this technology on the basis of P-type silicon wafers combined with TOPCon and IBC technology, in the back of the cell to build a fork PN junction, and the use of TOPCon tunneling passivation principle, while IBC has a front gateless line, Characterized by high conversion efficiency, the company is expected to form product differentiation and establish a new moat through this technology. In addition, LONGi has a layout in both HJT and TOPCon technologies, and has repeatedly set world records for conversion efficiency, highlighting the strength of the leader.
JinkoSolar: A leading enterprise in integrated components, N-type leads the technological transformation of the industry
The cumulative shipment volume ranked first, and the integrated production capacity continued to expand. As of September 30, 2021, the company's cumulative shipments reached 80GW, ranking first in the world. In 2021, the company's battery sheet projects such as Shangrao in Jiangxi, Chuxiong in Yunnan, and Hefei in Anhui were put into operation, with a balanced increase in production capacity and an improvement in integration efficiency. By the end of 2021, the company has a silicon wafer production capacity of 32.5GW, a cell of 24GW (including 0.9GW of N-type silicon wafers), a module production capacity of 45GW, and an estimated shipment volume of 23.55GW, ranking the forefront in the world.
N-type TOPCon cells are accelerated and have a first-mover advantage. The company is the first line component manufacturer in China to mass-produce and release N-type components. In 2018, the company invested in the establishment of a pilot line of N-type batteries, invested in a GW-level N-type battery test production line in 2019, and in 2021, the efficiency of the company's laboratory N-type monocrystalline cells reached 25.4%, and has achieved a stable mass production efficiency of 24.5%, with a yield rate of 99%. The company's 16GW N-type TOPCon battery project in Hefei phase I 8GW has been successfully rolled off the production line in January this year, and it is expected that the company's TOPCon production capacity will reach 16GW in 2022, and shipments will exceed 10GW. Compared to Perc, the N-type TOPCon is about 5%-6% faster in terms of efficiency and about 3%-4% higher in power generation performance, and the first-mover advantage of new technologies can make products more competitive while allowing companies to enjoy the premium of new technologies.
Excerpts from the report:
(This article is for informational purposes only and does not represent any of our investment advice.) For usage information, see the original report. ）
Featured report source: [Future Think Tank].