Asahi Kasei has opened a Hipore wet-process lithium-ion battery separator coating line at its Celgard plant in Charlotte, North Carolina.
The line gives the Japanese materials company its first North American coating and supply capacity for wet-process separators. Commercial production is scheduled to begin during the second half of its 2026 financial year, which ends in March 2027.
Asahi Kasei now producing both dry- and wet-process separators in Charlotte
Asahi Kasei held an opening ceremony on 20 August, coinciding with the 40th anniversary of the Charlotte factory. The site has produced Celgard dry-process battery separators since 1986 and will now supply both wet- and dry-process products.
Wet-process separators are manufactured by using a solvent to create microscopic pores in a polyolefin membrane. The separator electrically isolates a lithium-ion cell’s electrodes to prevent short circuits while allowing lithium ions to pass through the electrolyte.
Asahi Kasei has not disclosed the investment or production capacity attributable specifically to the Charlotte line.
The project forms part of a ¥40 billion ($270 million) expansion announced in 2023, involving additional coating equipment at existing plants in Charlotte, Hyuga in Japan and Pyeongtaek in South Korea.
Together, those investments were designed to add approximately 700 million square metres of annual coating capacity. Asahi Kasei said the expansion would raise its total separator coating capacity to around 1.2 billion square metres annually, sufficient for batteries in an estimated 1.7 million electric vehicles.
Toyota Tsusho America has secured a preferential share of the Charlotte plant’s output under a capacity rights agreement signed in 2025. Supplies of coated Hipore separator to the company are due to begin in mid-2027.
Asahi Kasei said the arrangement would help maintain utilisation of the coating line while giving Toyota Tsusho a stable regional source of automotive separator material. The volume covered by the agreement has not been disclosed.
Ryu Taniguchi, president of Asahi Kasei Battery Separator Corporation, said: “Opening the Charlotte coating line is a key milestone in establishing our North American supply platform for battery separators.
“By leveraging Celgard’s experienced workforce and established operations, we are expanding our North American product portfolio to include both Celgard dry-process and Hipore wet-process technologies.”
Asahi Kasei said energy storage systems were becoming an increasingly important source of North American battery demand as growth in the electric vehicle market moderated.
The company is also constructing an integrated Hipore base-film and coating plant at Port Colborne in Ontario, Canada, through a joint venture in which Honda holds a 25% interest.
The C$1.56 billion ($1.13 billion) plant was designed to produce 700 million square metres of coated separator annually, enough for about one million electric vehicles, and employ more than 300 people.
Commercial production was originally scheduled for 2027. Asahi Kasei was reported in April to have postponed the start until 2029 or later after Honda deferred its planned Ontario electric vehicle manufacturing complex amid weaker demand forecasts.
Construction work at Port Colborne has nevertheless continued. In its latest statement, Asahi Kasei said the project was “progressing according to plan”, but did not give a revised commercial production date.
Photo: ribbon cutting at the Charlotte, North Carolina plant (© Asahi Kasei)
