Establishment of joint venture in China for dry-process LIB separator | 2021 | News | Asahi Kasei
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Establishment of joint venture in China for dry-process LIB separator

September 22, 2021
Asahi Kasei Corp.

Asahi Kasei’s wholly owned subsidiary Polypore International, LP (Polypore) and Shanghai Energy New Materials Technology Co., Ltd. (SEMCORP) reached agreement in January 2021 to establish a joint venture in China for dry-process separator* for lithium-ion batteries (LIBs). With the receipt of the necessary regulatory approvals, the joint venture has been established as described below.

Based on a license from Polypore’s subsidiary Celgard, LLC, for technology and intellectual property related to dry-process polypropylene (PP) separator, the joint venture will manufacture and sell high-quality, high-performance dry-process separator in China for LIBs used in energy storage systems (ESS) and electric-drive vehicles (EDVs).

  • *A thin microporous film of polyolefin placed between the cathode and anode of lithium-ion batteries. It prevents contact between the electrodes which would cause a short, while allowing lithium ions to pass between the electrodes. Dry-process separator uses polypropylene (PP) as the main component and is manufactured with a solvent-free process. Wet-process separator uses polyethylene (PE) as the main component with plasticizer, and its manufacturing process uses solvent to extract the plasticizer.

The LIB market in China is the world’s largest and growing rapidly centered on EDV applications. As the Chinese government enacts policies for decarbonization, significant additional growth is forecasted in ESS applications in combination with renewable energy. The new joint venture is expected to meet growing demand for dry-process separators for ESS applications.

Corporate profile of the joint venture

Company name
Jiangxi Enpo New Materials Co., Ltd.
Gaoan City, Jiangxi Province, People's Republic of China
Paid-in capital
CNY 84 million (incremental rise to 454 million planned)
SEMCORP 51%, Polypore 49% (each indirectly through a subsidiary)
Manufacture and sale of dry-process LIB separator
100 million m2/year by mid-2022; 1 billion m2/year by 2028 planned

The joint venture will leverage Celgard’s cutting-edge dry-process separator production process technology, quality control know-how, and intellectual property rights in combination with SEMCORP’s top-level production process control and cost control capabilities in China to expand in the Chinese LIB market for ESS applications.

Celgard has been a market leader with research, development, and manufacturing know-how for over 40 years since inventing the dry-process LIB separator. With its manufacturing know-how for thin dry-process separator enabling higher energy density in high-performance LIBs, Celgard has provided customers with stable supply of high-quality cutting-edge separator essential for the manufacture of high-performance LIBs. Celgard has established a broad portfolio of patents for coated and uncoated LIB separator used not only in ESS but also in a wide range of EDV and consumer electronics applications.

SEMCORP is China’s leading manufacturer of wet-process LIB separator, with over 10 years of experience in the manufacture and sale of wet-process separator. With 6 manufacturing sites in China having a total production capacity of 3.5 billion m2/year, SEMCORP supplies over 100 different separator grades including base film and coated membrane. Leveraging its capabilities for stable quality, high yield, high productivity, and superior cost control, SEMCORP has established a track record of supplying top-tier LIB manufacturers.

The joint venture will provide advanced solutions to meet rapidly growing demand for LIB separator by adopting Celgard’s cutting-edge dry-process membrane technology, manufacturing know-how, and equipment through its technology license for single-layer PP and coextruded multi-layer PP membrane. It is scheduled to start production in 2022 with a capacity of 100 million m2/year with plans to raise capacity to 1 billion m2/year by around 2028 in line with demand growth.

“By joining Celgard’s specialized knowledge in technology, processing, and material science together with SEMCORP’s outstanding management ability in China, the joint venture will not only be able to provide a wide range of solutions to customers but also stimulate further development of the LIB industry overall,” notes Celgard President Lie Shi. “I am thrilled to have this partnership with SEMCORP. The joint venture will supply highly cost-competitive high-performance separator for LIBs in China for ESS and EDV applications. The combination of our two companies’ strengths will provide new solutions for the world’s challenges related to the environment and energy.”

“This joint venture will let us capture a huge opportunity in the ESS market with dry-process separator just like SEMCORP captured an opportunity in the EDV market with wet-process separator,” adds SEMCORP Chairman and CEO Paul Xiaoming Lee. “By combining Celgard’s highest-level technology and know-how with SEMCORP’s rich operational experience in China, track record of mass-producing high-quality separator, and cost-competitiveness, this joint venture with Polypore will be a revolutionary supplier of dry-process separator.”

About the Asahi Kasei Group’s LIB separator business

As a pioneer of LIB separator, Asahi Kasei has supported the development of the LIB industry since the dawn of the LIB in the early 1990s though the development, manufacture, and sale of Hipore™ wet-process separator. To keep pace with recent rapid demand growth accompanying the trend for electrification of vehicle drive systems, Asahi Kasei is expanding its plants in Moriyama, Shiga, and Hyuga, Miyazaki, Japan, to raise Hipore™ production capacity to 1.35 billion m2/year in fiscal 2023, approximately double the production capacity of fiscal 2020. Since acquiring Polypore, parent company of the leading dry-process separator manufacturer Celgard, in 2015, Asahi Kasei has supplied the LIB industry with broad-ranging solutions leveraging both wet-process and dry-process technology. The joint venture will license technology from Celgard, the leading dry-process separator manufacturer, and based on that technology will aim to develop the newly evolving ESS market in China. This will enable the entry into a new market which the Asahi Kasei Group could not develop independently, contributing to further growth. Asahi Kasei expects to contribute to a carbon-neutral society by supporting the growth and expansion of the LIB industry as a global leading LIB separator company.

About Celgard and Polypore

Celgard, LLC specializes in the development, manufacture, and sale of coated and uncoated dry-process microporous membrane used as LIB separator. Celgard, LLC is a wholly owned subsidiary of Polypore International, LP. Polypore specializes in microporous membrane for electric-drive vehicles, conventional vehicles, energy storage, and other special applications as a global company with sites in 9 countries around the world. For more information, please visit and


SEMCORP (formal name: Shanghai Energy New Materials Technology Co., Ltd.) is a global leader in the development and production of high-performance separator and coated separator for LIBs. SEMCORP currently has 6 manufacturing sites in China and is planning to expand to other countries in order to provide fuller services for EDV, consumer electronics, and ESS applications. For more information, please visit