A U.S. battery-cell factory that had been in the works between General Motors Co. and LG Energy Solution has been shelved indefinitely, people familiar with the matter said, marking a pause in the fast-growing partnership between GM and the Korean battery supplier.

Talks in recent months between GM and LG Energy executives ended without an agreement to move forward on what would have been the fourth U.S. battery plant to be developed by the companies through their 50-50 joint venture, Ultium Cells LLC, the people said.

GM executives over the past year have several times said they were close to outlining details for a fourth U.S battery-cell factory. Ultium Cells, run by executives from GM and LG Energy who were dispatched to the joint venture, operates a new plant in Ohio and is developing two others, one in Tennessee and one in Michigan, representing a total investment of more than $6.5 billion. 

GM is in discussions with at least one other battery supplier to proceed with an additional U.S. battery-cell factory, some of the people familiar with GM’s plans said. Details of those discussions couldn’t be learned. “We’ve been very clear that our plan includes investing in a fourth U.S. cell plant,” GM said, declining to discuss specifics.

GM said it is on track to hit one million EV sales annually in North America in 2025.

Plans for a fourth GM-LG factory were scratched in part because LG Energy executives in Korea were hesitant to commit to the project given the rapid pace of LG’s recent U.S. investments, some of the people familiar with the matter said. In addition to the three joint factories with GM, LG Energy last year disclosed plans for a battery-cell plant with Ram-maker Stellantis NV in Windsor, Ontario; as well as a joint factory with Honda Motor Co. , to be built in Ohio.

The uncertain macroeconomic outlook also was a factor in LG’s decision, some of the people with knowledge of the talks said.

As the GM-LG venture has evolved, the companies have been at odds on other aspects of the business, including the pace of ramping up production at the Ohio factory, which opened in late August, some people with knowledge of the relationship said. GM wanted a more-accelerated start of battery-cell output at the facility than did LG executives, the people said.

In September, GM Chief Executive Mary Barra

visited LG Energy’s headquarters in Seoul to meet with LG Energy Solutions Chief Executive Youngsoo Kwon to discuss the ramp-up plan for the Ohio facility, some of the people familiar with the matter said.

In October, Ms. Barra told Wall Street analysts that a slower-than-expected start at the Ohio plant would cause GM to miss its EV-sales target for North America through 2023. GM had expected to sell 400,000 EVs from early 2022 through the end of this year, but instead pushed out the time frame until mid-2024. Ms. Barra at the time said it took longer than expected to hire and train workers and establish operations at the facility.

Officials from the two companies also disagreed on the process for workers at the 900-employee Ohio factory to form a union, people familiar with the matter said. GM executives supported a so-called card check process, which is a less-formal and quicker path to unionizing than a confidential vote. LG executives rejected that idea and pressed to instead have the workers vote through a formal election.

In December, workers at the Ohio facility voted overwhelmingly to be represented by the United Auto Workers.

Ultium Cells last year disclosed that it was seeking tax incentives to potentially build a facility in Northwest Indiana, the intended site of the now-shelved facility. GM still is eyeing that location for a future cell factory, according to people with knowledge of the company’s plans.

Auto makers are racing to churn out electric cars, prodded by tightening environmental regulations globally and the success of Tesla Inc., whose value in recent years soared past those of traditional car companies. Strong consumer demand for the limited number of EVs on the U.S. market has added pressure on auto makers to scale up EV output, while also lining up future supplies of batteries and their raw materials.

For now, GM’s joint-venture arrangement with LG is critical to the auto maker’s ambitions to eventually overtake Tesla as the U.S. electric-vehicle sales leader. The Ultium partnership is the battery provider for many of the EVs that GM plans to introduce in the next few years using a new mechanical layout of batteries, motors and other components that can be used across multiple EV models.

Their partnership is among the first of several car-company tie-ups with battery makers aimed at securing enough supplies to support the auto industry’s ambitious EV production targets over the next decade.

Car makers and battery manufacturers in the last few years have outlined plans to build roughly a dozen large battery-cell factories in North America. In the last two years, the amount of investment pledged for battery production totaled nearly $40 billion, according to data from the Center for Automotive Research.

Write to Mike Colias at mike.colias@wsj.com and River Davis at river.davis@wsj.com