On April 11th, Narada launched the 690Ah ultra-large capacity energy storage battery, which marks a significant technological advancement for Narada in the era of large lithium-ion batteries, breaking through the current size specifications of 280/314Ah batteries and substantially increasing the capacity of individual cells.

The new energy storage battery, based on the 690Ah size specification, is compatible with capacities ranging from 650Ah to 750Ah. A 20ft energy storage system equipped with this battery is able to achieve a capacity up to 6MWh.

A variety of prominent technological innovations provide Narada 690Ah battery with an exceptionally long lifespan of over 20 years, a volumetric energy density of 380-440Wh/L, a cycle life of up to 15,000 cycles, and more than 2 kilowatt-hours of energy per cell, with an energy efficiency exceeding 96%. In the meantime, the system is able to maintain zero degradation over five years.

Five-Year 'Zero' Degradation Achieves Cost Reduction and Efficiency Improvement in Energy Storage Systems

Under the tide of ultra-capacity energy storage batteries, the core goal for most companies remains to further reduce costs. With larger battery capacities, fewer batteries and components are needed during the process of system integration, resulting in higher efficiency.

Compared to the industry-standard 280/314Ah battery solutions, Narada's 690Ah ultra-large energy storage battery achieves cost reduction and efficiency improvement across cell level, system level, and manufacturing, thus enhancing the overall profitability of energy storage projects.

At the battery level, the Narada 690Ah ultra-large energy storage battery would reduce the number of structural components such as battery cases and foil materials by 50%, while stacking efficiency is increased by 150%. From a system design perspective, the significant reduction in the number of battery series and parallel connections allows for a 50% reduction in system electrical connection components.

Compared to the 280Ah battery solution, the Narada 690Ah battery has achieved a reduction in comprehensive costs at the battery level of over 10%, while cost reductions at the PACK and system levels exceed 25%. Integration and manufacturing efficiency has been increased by 75% and 22% respectively. "This simplification in design makes battery management easier and significantly reduces system maintenance costs," said Jiayuan Xiang, Vice President and Chief Engineer of Narada.

Furthermore, batteries account for a significant portion of energy storage system costs, and battery degradation is a major concern for investors. The Narada 690Ah ultra-large energy storage battery employs a low-expansion, low-lithium-consumption negative electrode,  extremely stable electrolytes, and solid electrolyte technology. These features stabilize the anode interface and ensure uniform lithium distribution, addressing the challenges of anode collapse and lithium dendrites. Additionally, with dual lithium supplementation technology at both the cathode and anode, it compensates for lithium loss throughout the entire lifecycle, ensuring zero degradation over five years for the energy storage system.

How is the safety of ultra-large batteries ensured?

The larger the battery capacity and greater the heat generation accompany the increased risk of thermal runaway, which undoubtedly put forward more stringent demands on the inherent safety of the battery.

Narada begins with battery materials, utilizing solid electrolytes to construct quasi-solid lithium-ion conductive interfaces, reducing the amount of electrolyte by 30%, which results in fewer combustible components and significantly lower internal temperatures in the event of thermal runaway. Simultaneously, our company has made breakthroughs in halide electrolyte key material technology, achieving ionic conductivity close to 10-3S/cm, addressing the issue of poor conductivity in solid electrolytes.

To ensure battery safety, Narada optimizes design from multiple aspects including electrochemical systems, structure, and processes. Through the innovative application of SNS low heat generation technology, despite a 140% increase in energy capacity from 280Ah to 690Ah, the temperature rise during 0.5P charging and discharging remains below 4°C, and the maximum temperature after thermal runaway is reduced by 50°C.

Achieve superior cycling performance

Narada also seeks breakthroughs in enhancing battery cycle life on the basis of ensuring the safety. Narada 690Ah battery adopts the electrolytes that is extremely stable during high-temperature condition to suppress high-temperature side reactions, stabilizing the electrode interface and thereby achieving long cycle life.

Addressing the key technical challenges of more  cycles,  Narada 690Ah battery utilizes “ultra-low expansion coefficient, low lithium consumption synthetic graphite technology” and “dual lithium compensation  technology” to solve issues related to anode expansion and lithium loss.

Narada's independently developed “ultra-low expansion coefficient, low lithium consumption synthetic graphite technology” enables lithium-ions to preferentially intercalate into more stable graphite structures, effectively reducing the graphite expansion caused by lithium deintercalation. This technology reduces the expansion rate by 20%, enhancing the structural stability of the material.

Lithium loss in batteries directly impacts the lifespan of lithium batteries, hence safe and efficient lithium supplementation technology is crucial. Narada employs dual lithium supplementation technology at both the cathode and anode, precisely compensating for lithium loss throughout the entire lifecycle of the battery. This approach also allows for the controlled release of lithium-ions during the cycling process, enhancing both the cycling performance and energy density of the battery.

Zhiyou Mao, head of battery R&D of Narada, said, "To put it simply, the ultra-low expansion coefficient and low lithium consumption synthetic graphite technology enhance the battery's own 'immunity,' resulting in lower lithium loss; the dual lithium supplementation technology acts as an 'early energy replenishment.' Testing has shown that both technologies significantly improve the cycling performance of the Narada 690Ah battery, achieving a lifespan of ten thousand cycles.

Comprehensive coverage of both short and long-duration energy storage

To enhance the utilization rate of renewable energy and achieve GWh or even TWh level single-unit energy storage, there is an urgent global demand for long-duration energy storage. However, due to cost, technology, and other factors, most energy storage projects on the market currently depoy 2 to 4 hours system.

The Narada 690Ah ultra-large energy storage battery not only meets the needs for short-duration energy storage such as emergency frequency regulation and user-side emergency use but also satisfies the requirements for long-duration energy storage like grid peak shaving and supplementing electricity gaps. It achieves full-coverage application for energy storage scenarios ranging from 1 to 8 hours.

Additionally, the 690Ah battery addresses the pressing points of high costs and low efficiency in long-duration energy storage systems. "From the perspective of material performance and suitability for specific application scenarios, large battery lithium energy storage systems will be the ideal solution for electrochemical energy storage for some time to come," said Jiayuan Xiang.

Currently, the Narada 690Ah ultra-large capacity energy storage battery has passed various testing experiments, including short-circuit, overcharge, extrusion, nail penetration, and drop tests, and has obtained multiple safety certifications such as UL9540A, GB/T36276, UL1973, IEC62619, and UN38.3. It is scheduled for global delivery in September 2024.