China will account for more than 60% of the world’s production of wet-process separators for Li-ion batteries, with more than 10 billion square meters capacity, according to China-based market intelligence firm CCM. Now, Shanghai Energy, the largest supplier in the country, will build the largest production base, strengthening China’s leading role in the new energy industry.

Separators are a key element in rechargeable lithium-ion batteries with liquid electrolytes. During normal operation, the separator prevents electronic conduction (i.e., shorts or direct contact) between the anode and cathode while permitting ionic conduction. The separator also plays a safety role, shutting down at temperatures below those at which thermal runaway can occur.

Separators are usually manufactured via a wet or dry process. In the dry process, polypropylene (PP) or polyethylene (PE) is extruded into a thin sheet which is then annealed at 10-25 °C below the polymer melting point such that crystallite size and orientation are controlled. The sheet is then rapidly stretched in the machine direction to achieve slit-like pores or voids at 35-45% porosity.

Producing polyolefin separators in a “wet” or “gel” process involves the extrusion of a plasticizer/polymer mixture at elevated temperature, followed by phase separation, biaxial stretching, and extraction of the pore-former (i.e., plasticizer). The resulting separators have elliptical or spherical pores and porosity in the 40-50% range.

The resulting separators have strong chemical resistance, abrasion resistance, and good wettability with organic solvents, and have found wide use in lithium batteries.

According to CCM, China’s Li-ion battery separator industry will experience shift in the near future, preferring wet process separators for production instead of dry process separators.

In the past, the global lithium battery separator market was mainly shared by manufacturers in Japan, America, South Korea, and China. However, China has been making large investments in recent years for lithium battery manufacturing, which supports the goal to become the leading nation in the new energy market.

In 2016, Shenzhen Senior Technology Material sold 120 million square meters of dry-process separators, ranking first in China, followed by Cangzhou Mingzhu Plastic and Xinxiang Zhongke. In 2016, the sales leader of wet-process separator came to Shanghai Energy New Materials and it sold 100 million square meters, with customers including Samsung, LG, BYD, and CATL. In 2016, the top three by wet-process separator sales in China were Shanghai Energy, Suzhou GreenPower, and Foshan Jinhui Hi-tech Optoelectronic.

On 19 March 2018, Shanghai Energy held a signing ceremony for its new materials project in Wuxi City, Jiangsu Province. Reportedly, this project, located in Xishan Economic & Technological Development Zone with a total investment of USD789.24 million, is aimed at constructing 16 imported fully automated separator manufacturing lines, 40 coating lines and 5 imported aluminium-plastic film production lines, and establishing a premium marketed separator R&D center.

When the project is finished and put into operation, Shanghai Energy will become the world’s largest wet process separator producer.

Shanghai Energy, founded in 2010, is mainly producing wet process separator and functional coating separator for Li-ion batteries. It has more than 20 patents regarding technologies for Li-ion battery separator, separator deformation inspection equipment.

Shanghai Energy is now running 6 production lines. Meanwhile, it has 3 production bases respectively located in Shanghai, Dongguan and Zhuhai, combined production capacity at 320 million m²/a. To date, Shanghai Energy has established stable partnerships with many leading battery manufacturers such as LG Chem, BYD and Guoxuan High-Tech and has become the only certified supplier to Samsung SDI in China.

According to market intelligence firm CCM, China’s energy storage battery market developed vigorously in recent years. In 2017, the output of energy storage batteries increased by 13% YoY, and the corresponding output value was rising up by 7% YoY.

Though its future potential is predictable, the energy storage battery market is still restricted by relevant policies, pricing, electricity supply, among others. That is to say, energy storage batteries are still applied in a small range of areas. Its production capacity and growth rate both remain relatively small. Currently, the China-made energy storage battery is mainly used in communication base station, user-side peak shaving, off-grid power station, micro-grid, rail transit and UPS.

The battery separator industry in China is showing an incredible growth currently. This trend will lead very likely to a domination of this industry in the whole separator industry in the near future, CCM suggests.