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February 7, 2020

Volume 7 Issue 8

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Cutting Oils in Demand for Solar Panels

Vietnam’s increasing number of solar plant installations is boosting overseas demand for silicon wafer cutting oil used in solar panel manufacturing, an industry insider told Lube Report.

“The demand for lubricants in solar plants is limited and not large, but I think the demand for lubricants for silicon wafer cutting oil in the solar panel manufacturing process is still growing,” said Takeshi Mitomi, chief engineer of Idemitsu Lube Asia Pacific Pte.

However, “most silicon wafers are made in China. Therefore, it’s important to note whether silicon wafer cutting will be performed in Vietnam in the future,” when projecting potential demand for silicon wafer cutting oils in the country, he added. Some silicon wafers are manufactured in India and Taiwan.

Vietnam’s cumulative solar panel photovoltaic installation is expected to reach 5.5 gigawatts or 44 percent of Southeast Asia’s total capacity for 2019. In 2018, Vietnam had only 134 megawatts, or 0.134 GW, said Wood Mackenzie, a global consultancy, in a press release.

In March 2016, the Vietnamese government revised its National Power Development Plan 7 and increased the targeted share of electricity production from renewables – excluding hydropower – from 6.5 percent in 2020 to 10.7 percent in 2030. The government is preparing the draft for Plan 8 this year.

Vietnam does not manufacture finished solar panels. “Currently, solar panels are made and imported from China and India, so I believe the demand for lubricants in Vietnam is limited. Competition among silicon wafer companies is fierce worldwide, and players are being eliminated,” said Takeshi.

Some examples of wafer cutting fluid manufacturers in China are Liaoning Oxiranchem and Liaoning Kelongchem. Solar panels are made of polysilicon square ingot blocks, which are then ground and sawn into solid beams. Wire saws then slice those beams into thin wafers

Another company that makes silicon wafer cutting oils is Chemetall North America, based in the United States. According to its website, the sophisticated wire saws cut the beams using either diamond coated wire or slurry of silicon carbide. Thousands of wafers are sawn simultaneously on production wire systems, Chemetall states, and a wire failure must be avoided to prevent the loss of multiple, expensive wafers. Application of the optimum coolant for the diamond wire or the optimum silicon carbide slurry for plain, uncoated wire is mandatory to improve wire life and provide consistent sawing results, the company said.

According to Chemetall, wire sawing continues to evolve as demand for thinner wafers grows – which means more wafers per unit length of silicon block or ingot. Using thinner wire makes the saw more prone to breakage, the company states on its website, which requires new formulations of coolants, abrasive suspension vehicles and abrasive slurries.

“Technically, the trend [solar power panel manufacturing] is changing rapidly, and silicon wafer makers and lubricants makers need to constantly develop new products in anticipation of the next trend,” Idemitsu’s Takeshi added.

Takeshi said Idemitsu is developing new products with an evaluation machine dedicated to silicon wafer cutting in the laboratory. The company completed the construction of its solar power plant in Khanh Hoa Province, on the south central coastline of Vietnam, in May last year.

Solar panels at a site in Vietnam.

Photo: Nguyen Quang Ngoc Tonkin/Shutterstock

Photovoltaic solar panels at a site in Ninh Thuan, Vietnam. The country's increasing number of solar plant installations is boosting overseas demand for silicon wafer cutting oil used in solar panel manufacturing.