Apple Inc. has convinced a U.S. Patent and Trademark Office administrative law tribunal that prior inventions render some claims in a Uniloc 2017 LLC battery charging patent invalid.

The Patent Trial and Appeal Board voided more than half of the claims in Uniloc’s U.S. Patent No. 6,661,203, which involves “charging, discharging, and recharging rechargable batteries under adverse thermal conditions.” Apple had challenged the patent at the PTAB in an inter partes review, in which the board weighs the validity of patent claims in light of prior art.

The Aug. 19 decision is the latest in a running battle between Apple and Uniloc over technology patents that has played out at the PTAB and in courts.

Apple argued that two U.S. patents and a Japanese patent application rendered claims in the ‘203 patent obvious to a person of ordinary skill in the art, meaning an individual knowledgeable about the relevant technology.

Apple began its PTAB challenge to the ‘203 patent in 2018, after Uniloc sued the company in federal court for infringing the patent with its iPhones, iPads, and other devices. Uniloc has also accused HTC America Inc., LG Electronics USA Inc., and other large companies of infringing the patent.

Apple argued in its IPR petition that it could show that battery systems similar to those in Uniloc’s patent “were known in the prior art.”

Uniloc, in responding to the challenge, said in a filing that “conclusory statements” made by Apple “rely on speculation outside the four corners of a reference” and fall short of bringing a “prima facie case” on obviousness grounds.

The PTAB didn’t completely invalidate the ‘203 patent. Apple didn’t convince the board that the asserted prior art rendered four other claims of the patent invalid.

Ethridge Law Group, counsel for Uniloc, and Haynes and Boone LLP, representing Apple, didn’t immediately respond to requests for comment.

The case is Apple Inc. v. Uniloc 2017 LLC, P.T.A.B., No. IPR2018-00523, 8/19/19.