Separator is an important part of lithium-ion battery and its main function is to prevent electrical malfunction. The quality of the separator determines the battery’s capacity, cycle life span, and safety. It makes up 30% of the total manufacturing costs of a battery pack.

Asahi Kasei Corporation (Japan), Tonen Chemical Corporation (Japan), and Celgard (U.S) together control more than 80% global market share of separator. Due to high entry barriers such as technology intensity and high capital requirement, the investment risk is higher than other parts of supply chain resulting in fewer players in this particular field.

Coin-Nanotech Innovations Co. supplies separators for both Ni-MH and Lithium batteries in Taiwan while in China only Shenzhen Senior Technology Material Co. and Jinhui Hi-Tech of Foshan Plastics Group Co. are relatively mature in producing separators used in batteries.