Polypore’s Celgard Files Suit Against Sumitomo Over Batteries

Polypore International Inc.’s Celgard unit filed a patent-infringement suit against Sumitomo Chemical Co. over lithium-ion battery technology used in electronics and electric vehicles.

The complaint, filed Feb. 22 in federal court in Charlotte, North Carolina, claims Sumitomo is infringing a patent issued in 2002 for a separator in high-energy rechargeable batteries. The separators prevent short circuits that can reduce efficiency and limit safety problems from overheating.

Sumitomo Chemical makes the chemicals and materials for lithium ion batteries that use Celgard’s invention without permission, according to the complaint. The separators are used in batteries made by Panasonic Corp. for laptop computers, Celgard said in the suit.

“Celgard has a long history of innovation in lithium-ion battery separators and is a world leader in this technology,” Polypore Chief Executive Officer Robert Toth said in a statement. “We have a responsibility to our customers, partners, and shareholders to safeguard the investments we make in innovation.”

Tokyo-based Sumitomo Chemical has filed a trademark application to use the name “Pervio” for its separators, according to the complaint.

Polypore is seeking a court ruling that prevents the future use of the invention, plus cash compensation.

Polypore, based in Charlotte, also makes Duralife automotive batteries, and separators for health-care products like hemodialysis machines and beverage filtration machines. Weakness in the end market for electronic devices and electric vehicles were blamed for a 4 percent drop in fourth-quarter sales to $180.2 million, Polypore said Feb. 20.

The case is Celgard LLC v. Sumitomo Chemical Co., 13cv122, U.S. District Court for the Western District of North Carolina (Charlotte)