Tesla is expanding ties with South Korea’s LG Energy Solution, striking a deal to buy $4.3 billion worth of battery cells for energy storage systems that will be made in Lansing, Michigan.

The plant was formerly developed for a joint venture between LG and General Motors before the automaker decided to retreat from that initiative in late-2024, selling its stake to LG as part of a pullback in the automaker’s electric vehicle investments.

While Tesla still makes most of its revenue from EVs, the company is investing in its more rapidly growing energy business, as data centers drive up electricity demand. Tesla’s Megapacks can store power produced using intermittent sources like solar or wind, or during off-peak hours, then make it available for use when demand is high.

Tesla currently sells Powerwall backup batteries for residential use with its solar installations, and much larger Megapack and Megablock systems for utility-scale power storage. Last year, revenue in the company’s energy segment increased 27% to $12.8 billion, accounting for 13% of total revenue. Total revenue dropped due to a 10% decline in the auto business.

Details of the Tesla-LG partnership were announced during an Indo-Pacific Energy Security Summit in Japan, according to a release from the U.S. Department of the Interior. The Trump administration announced a total of $56 billion in private sector commitments at the event.

A spokesman with LG Energy Solution said the company “will establish dedicated production lines at our Lansing facility to deliver on this agreement.” LG last year retooled the facility to build LFP (lithium iron phosphate) prismatic cells, later confirming a $4.3 billion deal with an unnamed company.

GM continues to have a significant presence in and around the Lansing battery plant, but the company has largely retrenched from the EV market, announcing $7.6 billion in related write-downs.

Tesla, meanwhile, expects its energy business to “have very high growth for as far into the future as we can imagine,” CEO Elon Musk said during the company’s fourth-quarter earnings call in January. Chief Financial Officer Vaibhav Taneja cautioned that the energy segment expects “margin compression” from low-cost competition and the cost of tariffs.

Tesla’s competition includes companies like BYD in China and climate-tech startups like Form, which is making iron-air batteries, and others.

WATCH: Why the EV factory boom in the U.S. south is suddenly in trouble

Democratic Sen. Elizabeth Warren is calling President Donald Trump’s bluff after he claimed to be “ending” the affordability crisis during his State of the Union address, opening a new front in the battle that could determine November’s midterm elections.

“Your claims are directly at odds with the day-to-day experiences of American households, who are struggling with rising costs of essentials, including food, housing, health care, child care, and electricity,” Warren, D-Mass., wrote in a letter to Trump, which was shared exclusively with CNBC after being sent late Wednesday. 

“Despite your claims, you have not ‘solved’ affordability or ‘defeated’ inflation. Instead, over the past year, prices have skyrocketed for American households,” Warren, the top Democrat on the Senate Banking Committee, wrote.

Warren’s letter is the launching point for a frontal assault on Trump and congressional Republicans ahead of the 2026 midterms, which could be decided over affordability. Trump’s approval rating on the economy has plummeted as voters express concern about the high cost of living, a contrast with an economy he said was “roaring” during his State of the Union address. 

Now, Democrats are hoping to seize the opportunity to leverage affordability and kick Republicans out of power in Congress. Warren made clear the letter is only her first foray into knocking the president on affordability, as Democrats race around the country selling their economic message before November. 

“Over the coming weeks, I will be writing to Administration officials, companies, and industry representatives directly about your chaotic tariffs and failed economic policies — seeking answers for the American people who are being forced to pay more on everything from groceries to housing,” Warren said.

Warren late Wednesday also sent a letter to Amazon CEO Andy Jassy saying the online retailer was tardy in publicly saying that Trump’s tariffs had contributed to price increases on its platform since their enactment. She also asked Amazon to respond to a series of questions about its future plans on price hikes given Trump’s pledge to find ways tariffs in place. 

Trump has at times suggested he is getting serious about addressing affordability concerns. He’s called for a cap on interest on credit cards, which he did not mention in his speech. He’s also called for a ban on institutional investors from buying homes, which he did mention. Both are also priorities of Warren’s and the progressive left.

But in his State of the Union address, Trump laid blame solely on Democrats for affordability and argued his administration has solved the problem, as polls consistently show increased economic concern from voters. 

“You caused that problem,” the president said. “They knew their statements were a dirty, rotten lie. Their policies created the high prices, our policies are rapidly ending them.”

While overall inflation has cooled significantly from recent highs, the cost of many everyday goods remains high, especially compared to before the Covid-19 pandemic. Electricity prices have skyrocketed amid increased demand from data centers, grocery prices remain high and housing costs have remained inflated. Trump’s tariff agenda has also contributed to lingering high prices. 

Trump doubled down on issuing tariffs through other means during his address, after the Supreme Court knocked down the authority he had been using to implement them. 

The tariffs will “remain in place under fully approved and tested alternative legal statutes,” he said. 

To Warren, that only provided ammunition. 

“Rather than providing relief to consumers, you are pursuing additional across-the-board tariffs through other mechanisms — opening the door to yet another wave of price hike,” she said in her letter.