AsianFin -- In China's rapidly evolving energy storage market, the age of big battery cells has arrived—and with it, a heated race among giants like CATL, BYD, and EVE Energy to redefine how the world stores power.

Contemporary Amperex Technology Co. Ltd. (CATL), the world's top battery maker, on Tuesday announced the mass production and delivery of its latest large-capacity storage cell, a 587Ah model, marking its most aggressive move yet in an escalating capacity arms race.

The milestone comes just weeks after Envision AESC rolled its own 500+Ah cell off the line, and as SVOLT gears up for commercial production of a massive 770Ah unit later this quarter.

This surge in larger battery formats underscores an industry-wide shift: as costs per kilowatt-hour become the defining metric of competitiveness, companies are betting that bigger cells can unlock dramatic gains in energy density, system integration, and overall affordability.

"Bigger isn't just better—it's necessary," said Zheng Yelai, co-president of CATL's marketing division. "The goal is to simultaneously improve safety, performance, and cost-effectiveness. It's a full-stack optimization problem."

The race began in earnest in 2020, when CATL debuted its 280Ah battery cell. Within two years, that format had become the industry standard. By 2023, the market pivoted again, with leading manufacturers introducing 300Ah-plus cells to serve the growing demand for utility-scale storage. In 2024, EVE launched 628Ah cells, SVOLT unveiled a 710Ah version, and REPT followed with a 564Ah unit.

Now, with production lines humming and multiple players targeting mass deployment in 2025, the big-cell revolution is moving from the lab to the field. CATL's new 587Ah cell, manufactured at its Shandong facility, promises to cut system components by 40% and overall storage costs by 15%, according to the company.

It's a familiar playbook: reduce part count, simplify integration, and squeeze more energy into less space. For operators of grid-scale storage, where containerized 20-foot battery units are common, the math adds up. EESA estimates that switching from 280Ah to 314Ah cells in a 5MWh system can save $420,000 through fewer cells, lower infrastructure costs, and improved efficiency.

But making batteries bigger isn't just about scaling dimensions. As energy density rises, so do safety risks. A single defect in a high-capacity cell can trigger catastrophic failure. Globally, at least 167 safety incidents involving energy storage systems have been reported this year alone.

"The biggest issue we see today is the mismatch between advertised specs and real-world performance," said Zheng. "Cycle life claims often exceed 10,000 cycles, but actual projects show less than half that. Without standardized aging tests, buyers are flying blind."

Some manufacturers have tried to sidestep engineering challenges by simply stretching legacy cell designs. The result: reliability issues, overheating risks, and in some cases, project failures that have shaken investor confidence in the sector.

CATL says it took a different approach. Instead of enlarging cells or increasing compression, it focused on internal chemistry improvements—developing high-density cathode coatings and fast ion transport channels to achieve a 10% boost in volumetric energy density without compromising stability. Its 587Ah cell also uses a winding (jelly-roll) process rather than stacking, reducing cut points by 90 times and slashing self-discharge rates.

"We believe software and power electronics can't solve fundamental electrochemical flaws," Zheng added. "The weakest link still defines the system."

The timing is critical. In February, China scrapped its longstanding policy requiring new solar and wind projects to include energy storage—a signal that the sector is transitioning from policy-driven to market-driven. That puts intense pressure on battery makers to deliver solutions that not only work but pay off over the long term.

For CATL, that means optimizing everything from raw materials to system architecture. The company's "3D safety defense" strategy—featuring safe electrolytes, non-diffusive anodes, and heat-resistant separators—is designed to tackle thermal risks at the source.

At stake is more than just market share. As energy storage becomes a pillar of the global clean energy transition, the companies that master large-capacity cell technology will wield significant influence over future grid infrastructure.