Hithium unveils 587 Ah cell and 6.25MWh storage system

Chinese battery energy storage specialist Hithium presented its new ∞Cell 587Ah energy storage cell and the corresponding ∞Power 6.25MWh 2-hour storage system at the 13th Energy Storage International Conference and Expo (ESIE2025) in Beijing last week. The manufacturer also announced that the ∞Cell had begun global sampling in April 2025, with the ∞Power system slated for mass production in the second half of the year.

Engineers from Hithium explained the rationale behind the 587 Ah specification during the launch, underscoring the technical challenges that constrain energy storage design: container space, maritime transport weight limits (50t), the 1500 V system voltage ceiling, and the need to balance system architecture with the performance characteristics of lithium iron phosphate (LFP) chemistry. Rather than chasing ever-larger capacity for its own sake, Hithium grounded its innovation in practical limitations—such as the 20-foot container size and a 50-ton shipping threshold—and used those constraints as the basis for reverse-engineering an optimized cell.

The result is an energy density of 415 Wh/L, striking a balance between performance, safety, and competitiveness in levelised cost of storage (LCOS), the company says. Hithium’s engineering calculations, factoring in system voltage, weight constraints, and BMS chip capacity, concluded that a configuration of four racks with eight clusters in a >6MWh system provides the most efficient architecture for 2-hour energy applications. From this baseline, a multi-objective optimization algorithm pointed to 587 Ah as the ideal cell capacity for achieving cost-performance equilibrium.

Further, the cell’s dimensions—73.5 × 286 × 216mm—represent an optimal format that supports mechanical integrity, safety, and thermal efficiency, all while maintaining strong economic advantages, the company says. Building on this foundation, Hithium has enhanced the ∞Cell with improved materials, manufacturing processes, and structural design. The company reports that the 587 Ah cell achieves a 94.5% energy efficiency rate, a cycle life exceeding 10,000 cycles, and compliance with both GB/T and UL safety standards. Compared with a 314 Ah cell, the ∞Cell offers a 6.5% increase in volumetric energy density.

The cell is integrated into Hithium’s newly launched ∞Pack+ platform, designed for universal application across large-scale storage projects. The ∞Power 6.25MWh 2-hour system fits within a standard 20-foot container and boasts five core features: standardization, ease of maintenance, high safety, efficient internal layout, and broad compatibility. To streamline operations and maintenance, the system incorporates Hithium’s patented external active balancing technology, which enables maintenance without shutdown, cutting service time by an estimated 90%. A newly developed triple shut-off valve addresses typical liquid cooling system maintenance bottlenecks, reducing fault-handling time by over 60%.

On the safety front, the system includes ultra-low thermal conductivity insulation pads that meet the latest GB/T 36276-2023 safety and thermal runaway standards. It also features a dual-layer Battery Management System (BMS), combining functional safety with cybersecurity protection and achieving a SIL2 safety level.

Hithium stated that several downstream system integrators have already begun incorporating the 587Ah cell into their own storage platforms. The company believes the 587Ah specification is poised to become a new industry benchmark for LFP-based storage capacity.

Founded in 2019, Hithium quickly emerged as a prominent force in electrochemical storage innovation. From 2022 to 2024, its batter cell sales surged from 3.3 GWh to 28.3 GWh, while storage system deliveries grew from 1.0 GWh to 5.3 GWh.

According to the 2024 global energy storage battery shipment rankings by the China Energy Storage Alliance (CNESA), Hithium now ranks third among Chinese companies, trailing only CATL and EVE Energy.