With the major technological changes in most links of the photovoltaic industry chain slowing down, 0BB (no main grid) technology is becoming the main technology for the industry to reduce costs and increase efficiency. The industry believes that 0BB technology has developed from "optional" to "mandatory", which is the optimal solution for N-type photovoltaic modules to reduce costs and increase efficiency.

0BB technology is accelerating import

Shen Wenzhong, director of the Solar Energy Research Institute of Shanghai Jiaotong University, regards 0BB technology as one of the biggest highlights of technological progress in the photovoltaic industry this year. He said: "Heterojunction and 0BB technology have more advantages in structure and more obvious cost reduction. 0BB technology can reverse the disadvantage of heterojunction in single watt cost."

the reporter noticed that BC route (back contact technology) recently released 0BB technology developed based on metal copper coating on behalf of enterprise aixu stock (600732.SH), becoming the first enterprise to apply 0BB technology in photovoltaic BC cell technology route. Jingke Energy (688223.SH) said that the company has a clear plan for future efficiency improvement and cost reduction, and 0BB technology has been introduced on schedule. Tongwei Stock (600438.SH) introduced 0BB technology in July last year, in December of the same year, the conversion efficiency of the heterogeneous junction 0BB module reached 24.31%.

OBB technology is essentially an evolution of the gate line process.

Different from MBB (multi-main gate) and SMBB (super multi-main gate) technology, OBB technology improves the light receiving area by not printing the main gate at the battery end. The thinner the gate line, the more beneficial it is to reduce the amount of silver paste to reduce the cost, while reducing the shading of the battery sheet and improving the power generation efficiency.

Xia Hengliang, deputy general manager of Aixu, told reporters: "The 0BB technology of photovoltaics means removing the main grid and directly connecting the solder ribbon and the fine grid. After removing the main grid, the light receiving area of the battery increases, and the electrical loss is reduced due to the shorter path of electronic transmission."

from the perspective of manufacturing, BC technology superimposes OBB technology, which means that after all the main grid and fine grid on the front are moved to the back of the photovoltaic module, the number of solder joints on the back of the photovoltaic module is at least 25% more than that of OBB of other technologies. In the case of the same area, the welding point is 25% more, and the process difficulty is greatly improved.

"At present, the above-mentioned difficulties in manufacturing have been overcome and are moving towards large-scale commercial use." According to Xia Hengliang, the company's 0BB technology adopts silver-free metal coating process and copper electrodes. Under external force or harsh thermal expansion and cold contraction environment, the welding belt and electrodes are not easy to separate, which can solve the problems of photovoltaic BC battery heating warpage, welding uniformity, battery chip crack rate, etc.

according to the first financial reporter, at present, in terms of TOPCon (tunneling oxide layer passivation contact technology) and 0BB technology, chint group has completed GW-level mass production, jingke energy is about to enter GW-level mass production, trina solar energy, a new energy and other enterprises are also in the layout. In terms of heterojunction and 0BB technology, Oriental Sunrise (300118.SZ) has completed mass production, Tianhe Solar Energy, Tongwei shares are also in the layout.

Cost Reduction Advantage

Silver paste accounts for about 37.5 percent of the non-silicon cost of PERC batteries (P-type battery technology).

From an economic point of view, in order to further reduce the unit silver consumption and thus help reduce the cost of photovoltaic modules, the market research and development direction towards 0BB technology, that is, the use of copper wire welding belt instead of the original silver main grid directly to collect the fine gate current, and to achieve the interconnection between the cells.

"The price of silver may soon be so high that solar power cannot afford it." The head of a photovoltaic cell factory told First Financial Reporter that the amount of silver used by photovoltaic has accounted for more than 15% of the global silver production. The agency predicts that the global silver production this year will be 31000 tons, of which 26300 tons are primary (mineral silver) and 5800 tons are recycled silver. However, the demand for silver this year is 36000 tons, which means there is a shortage of 5000 tons of silver.

"The company has completed the full import of laser-assisted sintering technology, and 0BB technology has completed preliminary testing, which can significantly increase power and reduce costs, and will be gradually imported in accordance with the company's plan." Jingke Energy's management recently said during the 2023 performance presentation that the combination of 0BB technology and special network board technology is expected to be reduced to about 80mg/tablet by the end of this year. Silver-clad copper and copper electroplating technologies have been simultaneously validated and are expected to have the opportunity to be applied to production in the next two years.

In addition, in the context of the photovoltaic in the downward cycle, the industry's demand for 0BB this cost-effective process is more urgent.

Take the current mainstream N-type technology-TOPCon technology and heterojunction technology as an example. According to agency estimates, TOPCon technology into 0BB technology, the total manufacturing cost decreased by about 0.012 yuan/watt to 0.019 yuan/watt; heterojunction technology into 0BB technology, the total manufacturing cost decreased by about 0.042 yuan/watt to 0.050 yuan/watt. Assume that the unit value of the new 0BB string welding machine is 0.021 billion yuan/GW, and the unit value of the 0BB string welding machine of the stock transformation is 0.015 billion yuan/GW.

String welding companies are expected to benefit

The string welding equipment is the core link to realize the 0BB process.

The industry believes that with the gradual introduction of OBB technology into TOPCon and heterojunctions, related equipment such as string welders and auxiliary materials (welding belts) are expected to be the first to benefit.

take otvey (688516.SH) as an example, the company released a message in mid-March this year, saying that at present the company's 0BB technology has broken through the technical bottleneck on TOPCon, reducing the silver consumption of a single chip by more than or equal to 10%, and increasing the power of photovoltaic modules by more than or equal to 5W, thus realizing cost reduction and efficiency increase for photovoltaic products.

"The company has completed more than 120 related patent applications and has now reached the conditions for mass production of the TOPCon 0BB welding process." Otway said.

Guojin Securities predicts that by 2026, the market space corresponding to 0BB string welding machine will be 8.4 billion yuan, and the market space is expected to reach 19.4 billion yuan from 2024 to 2026. Head string welding equipment manufacturers are expected to benefit directly.

However, the penetration of the 0BB process requires downstream PV module manufacturers to make corresponding capital expenditures on the equipment side, and if PV module prices remain depressed, it will put more pressure on the profitability of the industry, thus affecting the equipment orders of the related companies.

There are also potential risks that the 0BB process is not progressing as expected. Guojin Securities believes that 0BB photovoltaic module series welding accuracy requirements are high, domestic manufacturers in the technical route of the different emphasis may lead to the dispersion of research and development forces. If the slow progress of 0BB process development delays the full introduction of 0BB technology in PV modules, it may have an impact on the performance of the relevant companies.