Views: 0 Author: Site Editor Publish Time: 2026-01-16 Origin: Site
As the global energy transition accelerates, demand for large-scale energy storage systems (ESS) continues to rise sharply. At the same time, battery manufacturers are moving beyond incremental capacity upgrades and focusing instead on structural innovation and manufacturability.
Among the most important recent milestones is the successful mass production of 684Ah stacked pouch cells—a development that signals a new phase for large-format lithium battery technology.
In late 2023, Sunwoda announced that its production line had delivered over one million 684Ah stacked cells within just three months, demonstrating that stacked large-format pouch cells are no longer laboratory concepts, but commercially scalable products.
More importantly, this milestone reflects a broader industry shift:
from competing on cell size alone to optimizing structure, safety, and manufacturing consistency.
Million-level production confirms stacked pouch cells are ready for utility-scale deployment
Stacked architecture outperforms wound formats in safety, energy density, and lifecycle at capacities above 500Ah
Advanced automation and AI inspection reduce defect rates to PPB levels
Over 70% of leading battery manufacturers are now investing in stacked cell platforms
684Ah stacked pouch cells are becoming a preferred format for grid-scale ESS
A 684Ah stacked pouch cell is a high-capacity lithium-ion cell designed specifically for stationary energy storage.
Unlike traditional wound (rolled) cells, stacked pouch cells assemble cathode, separator, and anode layers in a flat, book-like structure.
This design eliminates internal bending stress, enables full-tab current collection, and improves thermal uniformity—advantages that become critical once cell capacity exceeds 500Ah.
At this scale, wound architectures struggle with:
Uneven internal pressure
Corner stress concentration
Increased lithium plating risk
Complex thermal gradients
Stacked pouch formats maintain structural integrity while supporting much larger electrode areas, making them naturally suited for ESS applications.
Historically, stacked cells were considered difficult to manufacture at scale due to alignment sensitivity and contamination risks.
Recent production lines have solved these challenges through:
Multi-layer particle prevention systems
Ceramic edge sealing and hi-pot insulation testing
High-precision 3-axis stacking platforms
Anti-wrinkle lamination processes
Modern quality control now integrates:
1,500+ sensors with AI vision inspection
2.5D optical detection
Full-line CT scanning for internal defects
These systems push defect rates down to PPB levels—making stacked pouch cells viable for long-life ESS deployment.
While wound cells remain dominant in EVs and consumer electronics, their limitations become apparent in ultra-large formats.
| Feature | Wound Cell | Stacked Pouch Cell |
|---|---|---|
| Energy Density | Moderate | Higher (no R-corner loss) |
| Internal Resistance | Higher | Lower (full-tab structure) |
| Thermal Uniformity | Uneven | Highly uniform |
| Mechanical Stress | Concentrated | Evenly distributed |
| Safety Margin | Lower | Higher |
| Scalability >500Ah | Limited | Ideal |
For cells above 500Ah, stacked pouch architectures offer clear advantages in reliability, thermal behavior, and manufacturability.
The move toward stacked large-format pouch cells is not isolated.
More than 70% of major battery manufacturers are actively deploying or expanding stacked production lines, including:
CALB
SVOLT
EVE Energy
REPT BATTERO
Sunwoda
This reflects a strategic transition away from simple capacity scaling toward platform-level optimization.
By 2026, production capacity for 600Ah+ stacked pouch cells is expected to increase substantially, driven primarily by grid-scale ESS demand.
For system integrators and project developers, 684Ah stacked pouch cells enable:
Fewer cells per rack, reducing system complexity
Lower internal resistance, improving round-trip efficiency
Improved thermal stability, lowering runaway risk
Longer cycle life, reducing total cost of ownership (TCO)
At the system level, this translates into:
Simplified BMS architecture
Lower BOM cost
Easier thermal management
Higher long-term reliability
Modern ESS platforms are already adapting with stacked-cell-compatible BMS and liquid cooling solutions.
The mass production of 684Ah stacked pouch cells marks a structural turning point for energy storage.
It demonstrates that ultra-large, high-performance lithium cells can now be manufactured reliably and economically—unlocking new levels of scalability for renewable integration and grid stabilization.
While cylindrical and prismatic formats still serve many markets, stacked pouch cells are rapidly becoming the foundation of next-generation utility ESS.
They represent not just larger batteries—but a more mature balance of safety, manufacturability, and lifecycle performance.
At Misen Power, we specialize in stacked pouch cell platforms and customized ESS battery modules, supporting applications from commercial storage to utility-scale deployments.
From cell selection to system integration, we help bridge manufacturing reality with energy storage performance.
Contact us to discuss your project.
As the global energy transition accelerates and demand for renewable energy storage systems (ESS) continues to surge, battery technology is advancing rapidly to meet the challenge. Among the latest breakthroughs, the successful mass production of 684Ah stacked battery cells has captured industry attention and signaled a new era in large-format energy storage.
On December 23, 2023, battery manufacturer Sunwoda announced that its production line had delivered 1 million 684Ah stacked cells in just three months — a milestone that confirms the maturity of stacked battery cell technology and its readiness for large-scale deployment.
1 million 684Ah stacked cells produced in only 3 months, proving large-scale manufacturability.
Stacked cells outperform wound cells in safety, energy density, and cycle life—especially above 500Ah.
Advanced manufacturing & AI inspection reduce defect rates to PPB levels.
Over 70% of top battery makers are now investing in stacked cell technology.
684Ah stacked cells are becoming the preferred solution for utility-scale energy storage systems.
A 684Ah stacked battery cell is a high-capacity lithium-ion cell designed specifically for energy storage applications. Unlike traditional wound (or rolled) cells, where the electrodes and separator are wound into a spiral, stacked cells assemble these layers in a "book-like" fashion — layer by layer.
This structural difference eliminates internal stress points (common in wound cells), enables higher energy density, and improves overall thermal management. It's particularly effective for battery formats above 500Ah, where roll-based designs become difficult to manufacture safely.
One of the key challenges in stacked battery cell production has been minimizing defects such as particles, burrs, misalignments, and wrinkling during the stacking process. Sunwoda's achievement in producing 1 million cells in 3 months was made possible through a series of innovations:
Four-layer particle prevention system to eliminate contamination.
Hi-pot insulation testing and CIL ceramic edge-sealing to enhance electrical safety.
3-axis alignment platforms for precision stacking.
Triple-layer anti-wrinkle pressing technology.
On the quality control side, the production line includes:
230+ inspection items using 1,500+ sensors and AI vision systems.
2.5D image detection and full-line CT scanning for internal defects.
Achieving a PPB (parts per billion) defect level, ensuring reliability at scale.
While wound cells (cylindrical or prismatic) remain dominant in smaller applications like EVs and portable electronics, stacked cells offer unique advantages for high-capacity storage:
| Feature | Wound Cell | Stacked Cell |
|---|---|---|
| Energy Density | Moderate | Higher (no wasted R-corner space) |
| Internal Resistance | Higher | Lower (due to full-tab design) |
| Thermal Management | Less uniform | More uniform |
| Structural Stress | High at corners | Evenly distributed |
| Safety | More prone to lithium plating | Lower risk of short circuits |
| Scalability (>500Ah) | Limited | Ideal |
For cells above 500Ah, the wound process struggles with mechanical stress and uneven pressure distribution, while stacked designs maintain integrity, performance, and safety over long-term usage.
The 684Ah stacked cell is not just a technological leap for one company — it's a broad industry trend. Over 70% of leading battery manufacturers are actively developing or scaling up stacked cell production, including:
CALB
SVOLT
EVE Energy
REPT BATTERO
Sunwoda
This trend reflects the industry's shift from competing on cell size alone ("dimension race") to focusing on high-performance, scalable manufacturing processes.
By 2026, the production capacity of 600Ah+ stacked cells is expected to increase significantly, driven by growing demand from grid-scale ESS providers.
For utility-scale storage systems, the 684Ah stacked cell offers multiple system-level benefits:
Fewer cells per rack, simplifying system design and reducing BOM cost.
Lower internal resistance, improving round-trip efficiency.
Higher thermal stability, lowering the risk of thermal runaway.
Longer cycle life, reducing total cost of ownership (TCO).
System integrators are also adapting quickly, offering stacked-cell-compatible battery management systems (BMS) and thermal solutions, ensuring seamless integration into commercial and industrial energy storage deployments.
The mass production of 684Ah stacked battery cells marks a pivotal moment in the evolution of energy storage. It proves that high-capacity, high-performance batteries can now be manufactured at scale — cost-effectively and reliably.
As more manufacturers and energy providers embrace this advanced cell format, we can expect a new wave of efficient, safe, and scalable energy storage solutions to emerge — helping to accelerate the world's transition to clean energy.
Stacked cells assemble electrodes in layered formats, while wound cells roll them into a spiral. Stacked cells offer better energy density, lower internal stress, and improved thermal performance, especially in large-capacity formats.
684Ah represents a new benchmark in cell capacity for energy storage systems. It allows for fewer cells per rack, reducing complexity, improving efficiency, and lowering overall system cost.
Yes. Stacked cells have fewer stress points, lower expansion rates, and better thermal distribution, which significantly reduces the risk of lithium plating, internal short circuits, and thermal runaway.
Leading battery manufacturers like Sunwoda, EVE Energy, CALB, and SVOLT have already incorporated stacked cell lines into their production, with growing adoption expected globally.
Larger, safer, and more efficient battery cells enable scalable and cost-effective energy storage systems, which are critical for integrating renewable energy and balancing grid demand.
