Lithium-ion Battery Separators: Innovation Is the Key

By Sun Dongquan, China Plastics Processing Industry Association

Upsurge expected for China-made alternatives

Sixty one enterprises have announced plans to invest in the lithium-ion battery separator sector in China, of which 19 in vesters confirm to use wet process and 29 investors faver dry process. In 2016, China’s capacity to make lithium-ion battery separators reached 2.3 billion m2/a, output was expected to grow 70.21% YoY, and the market share of China-made products climbed constantly.
Rapid capacity expansion drove prices all the way down: the average annual price of lithium-ion battery separators made by a wet process was RMB6.2/m2 in 2013, and around RMB4/m2 in October 2016, down nearly 50% during that period. The average annual price of lithium-ion battery separators made by the dry process was around RMB2-3/m2, down significantly from three years ago (see Figure 1).
New projects identified for the 13th Five-year Plan period (2016-2020) are listed in Table 1. In addition, it is estimated that more than 10 other Chinese companies intend to enter the sector, and total capacity is expected to exceed 4.0 billion m2/a by the end of 2018. Competition will be fiercer, and profitability will decline further.
Foreign producers and local enterprises presently coexist in China separator market. Low-end and mid-market is diversified, competition is fiercer, and local producers dominate there. However, in the mid-and high-end market, where technical thresholds and product quality are high, foreign enterprises and a few leading domestic enterprises now dominate, but it is expected that an upsurge of China-made alternatives will appear during 2017-2018. And then in 2019, China will achieve self-sufficiency of 80% with regard to lithium-ion battery separators, leaving only a small-volume market share for imported products.  

Wet process and dry process promote each other in competition

In the last two years, with the power battery market blossoming, wet-coating separators have been increasingly popular. According to a survey, few enterprises own dry biaxial stretching technology, but the demand for dry biaxially stretching coated separators is growing rapidly.
At present, the shipment growth of separators made by a dry process is due mainly to the dry uniaxially stretching separators, while the shipment growth of separators made by a wet process is driven by the power market, replacing imports and export growth. The wet process has been embraced by domestic lithium-ion battery and separator enterprises. At present, most producers still use production lines imported from Japan, Korea, Europe and the United States; and China-made wet separator equipment has great market prospects.
The dry process and wet process compete with each other and promote each other. The wet separators combining with coats are highly acclaimed in ternary systems, the dry biaxially stretching coated separators have great room for growth in ferric lithium phosphate battery applications, and three-layer composite separators will probably become the highlight among dry biaxially stretching coated separators.

Table 1   New lithium-ion battery separator projects identified for the 13th Five-year Plan period (2016-2020)

Producer    Process    Number of production lines    Capacity
(million m2/a)
Hunan Chinaly New Material Co., Ltd.    Wet    8    200
Tianjin DG Membrane Tech Co., Ltd.    Wet    4    200
Sinoma Science & Technology Co.,  Ltd.    Wet    4    200
Anhui Tianhong New Material Shares Co., Ltd.     Dry biaxial stretching     2    
Cangzhou Mingzhu Plastic Co., Ltd.     Wet    6    180
Huianhui (Tianjin) New Energy Technology Co., Ltd.            
Suzhou GreenPower New Energy Materials Co., Ltd.    Wet    4    150
Hefei Jieshi New Materials Co., Ltd.        10    
Liaoyuan Hongtu LIBS Technology Co., Ltd.    Wet    1    45
Chongqing Yuntianhua Newmi-Tech Co., Ltd.    Wet    6    250
Hefei Senior New Energy Materials Co., Ltd.    Wet    6    250
Zhejiang Nanyang Technology Co., Ltd.    Dry biaxial stretching    1    90
Henan Xinxiang Xinrui Battery Material Co., Ltd.    Dry biaxial stretching    1    40
Jiangmen Loongcentury Technology Co., Ltd.?     Dry uniaxial stretching    2    80
Jiangsu Anreda New Materials Co., Ltd.     Dry uniaxial stretching    2    80
Foshan Yingbolai  Technology Co, Ltd.?     Dry uniaxial stretching    1    40
Anhui Tongling Crystal Electronic Co., Ltd.    Wet    2    80
Hunan Runyuan New Materials Co., Ltd.    Wet    2    80


Localization of production lines

At present, most of China’s separator production equipment is imported. Qingdao Zhongkehualian New Material Co., Ltd. has ability to compete with foreign makers of wet process equipment. To compete in manufactur dry process equipment, local enterprises like Guilin Electrical Equipment Scientific Research Institute and Beijing Research Institute of Automation for Machinery Industry still need to catch up.
In addition, domestic enterprises should pay attention to the development of special separator for materials. Sinopec Beijing Research Institute of Chemical Industry has developed China-made special material for dry process lithium-ion battery separators, and after the promotion conducted by the BOPP Special Committee of China Plastics Processing Industry Association in the last three years, this material is used by separator makers. Sinopec Shanghai Research Institute of Petrochemical Technology is developing a specialty material for wet process lithium-ion battery separators, and will also conduct its promotion and application.
The domestic separator market will develop toward high-end separator products with high porosity and thin film. For example, China Haisum Engineering Co., Ltd. tries to manufacture lithium-ion battery separator by paper-making method, has achieved favorable initial results in laboratory research. The company’s next major effort is research on related technologies that meet industrialization requirements and gradual expansion of the power of test batteries, so that the research project can eventually meet the requirements of industrialization.