April 9 (Reuters) - Duracell, the battery maker owned by

Warren Buffett's Berkshire Hathaway ( BRK/A ), has been sued by

BASF for allegedly stealing trade secrets related to

the German chemical company's lithium ion battery technology,

court documents showed.

In a heavily redacted complaint made public on Tuesday in

Delaware federal court, BASF said the trade secrets related to

its efforts over several years to manufacture lower-cost

materials for high-powered batteries.

Duracell did not immediately respond to requests for comment

on Wednesday.

In the complaint, BASF said it invested substantial

resources in creating a proprietary and trade-secret process for

producing high-performance cathode material, a battery component

it called "crucial".

But it said Duracell misappropriated secrets while the

companies had a collaboration agreement, shared details with a

third party, and arranged for manufacturing under the false

pretense that BASF's process came from Duracell.

By "cutting BASF out of its role as developer and supplier,"

Duracell caused "substantial and irreparable injury," justifying

damages, BASF said.

Lithium ion batteries are used in many products including

consumer electronics, electric vehicles, appliances, toys and

energy storage systems.

BASF announced a plan in December 2023 to separate its

battery chemicals business and two other businesses into

autonomous units, to help boost earnings.

Berkshire bought Duracell from Procter & Gamble ( PG ) for

about $2.9 billion in 2016.

The case is BASF Corp. v. Duracell U.S. Operations Inc, U.S.

District Court, District of Delaware, No. 25-00404.