The United Auto Workers strike against the Big Three U.S. automakers continues, but union President Shawn Fain said Friday that the labor stoppage isn't expanding as the walkout closes out its third week.

In a 2 p.m. Facebook Live event, Fain said General Motors agreed in writing that electric battery manufacturing will be covered in the next contract between GM and the union. He described that as a major win that will change the auto industry.

He said the threat of a strike at another major GM plant convinced the company to change its stance.

"We were about to shut down GM's largest moneymaker in Arlington, Texas," Fain said. Full size-SUVs for the Chevrolet, GMC, and Cadillac brands are made there.

Electric vehicle manufacturing plants, and the people who work there, have been an important point in the strike. The employees at those plants aren’t members of the UAW, and they make less money than union members.

Ford, GM, and Stellantis, the former Fiat Chrysler, all partner with South Korean companies to make those batteries.

“We've been told the EV future must be a race to the bottom, and now we’ve called their bluff," Fain said. "The plan was to draw down engine and transmission plants, and permanently replace them with low-wage battery jobs."

General Motors said it is continuing to negotiate. It did not confirm the concessions Fain described.

About 25,000 auto workers have gone on strike since the UAW's contract with Ford, Stellantis, and General Motors expired at midnight ET on September 15. It was the first time the union simultaneously went on strike against all three companies.

Since then, the UAW had announced additional strike locations every Friday, with more workers walking off the job at noon ET each time. That changed this week.

The UAW's other demands

The union wants to include 40% annual pay raises over four years; a 32-hour workweek, down from the current 40; an end to wage tiers; better pensions for retirees; cost of living adjustments; and improved healthcare. They cite record profits for the car companies in recent years and the benefits union members gave up after the 2007-08 Great Recession nearly took down the Big Three.

The automakers have offered record contracts with pay increases of around 20% as well as bonuses and other improved benefits, but that hasn’t been enough to keep the strike from stretching on.

While workers from all three companies are striking, the UAW has spared the companies additional strikes at different times to reward them for making progress in talks. A week ago, GM and Ford were targeted for strike expansions while Stellantis, which makes Dodge and Chrysler and Jeep vehicles, was not.

It's a strategy intended to keep the companies off-guard and snarl their production and supply lines while taking fewer workers off the job. Soon after it started, the automakers began laying off workers in various locations, saying there was no work for them because of strikes elsewhere.

GM has laid off more than 2,100 employees since the strike began, with Ford adding more than 600, and Stellantis has furloughed around 370 people.