Tesla’s battery ambitions face new setback

The issue surfaced after Tesla quietly introduced its own 4680-based battery packs in some European Model Y Long Range vehicles, replacing supplier-made batteries without notifying customers. Some drivers described the change as a downgrade because of reduced driving range and slower charging performance, News.Az reports, citing Korea Herald.

Tesla’s new battery pack reportedly reduced the vehicle’s driving range from 661 kilometers to 609 kilometers. The company’s in-house cells were also said to have lower energy density than LG Energy Solution’s batteries and required more time to charge from 10% to 80%.

The controversy has renewed debate over Tesla’s long-running attempt to reduce dependence on outside battery suppliers. When Elon Musk introduced the 4680 battery program in 2020, he described it as a major technological breakthrough designed to cut costs and improve efficiency.

Industry experts, however, say large-format battery production is far more complex than simply increasing battery size. According to a senior researcher at a major Korean battery manufacturer, larger cells create additional challenges involving heat control, internal resistance and consistent energy distribution.

The researcher compared the process to cooking multiple packs of noodles at the same time, saying larger batteries require much more precise thermal management to avoid uneven performance inside the cell.

The report also highlighted the technological advantage Korean battery companies have built through years of mass-production experience. Experts said firms such as LG Energy Solution and Samsung SDI continue to lead in manufacturing stability, charging efficiency and quality control for next-generation cylindrical batteries.

Tesla has been steadily expanding its internal battery production strategy since partnering with Panasonic at Gigafactory Nevada in 2017. Controlling battery manufacturing is considered critical because batteries account for roughly 30% to 40% of an electric vehicle’s total cost.

Despite Tesla’s push for independence, the latest developments suggest the company may still face major hurdles in scaling advanced battery technology for mass production.