H.E.L Group has successfully completed thermal runaway testing on a 790Ah utility-scale battery cell using its BTC-500 Large Battery Adiabatic Calorimeter, providing critical safety data for one of the largest lithium-ion cells currently in production.
Developed by Envision AESC, the 790Ah prismatic wound-type cell represents a major step forward in battery design, delivering an energy rating of 2528Wh and a volumetric energy density exceeding 440Wh/L. Its introduction marks a wider industry shift beyond the “500+Ah era” toward next-generation, ultra-high-capacity formats.
From Capacity Expansion to Safety Assurance
As cell capacities continue to increase, the industry’s focus is evolving. The key question is no longer how large battery cells can be made, but how their safety and stability can be maintained at scale.
Higher-capacity cells concentrate significantly more energy within a single unit, increasing the complexity of thermal management and the potential impact of failure events such as thermal runaway. Variations in internal reactions, temperature distribution, and mechanical integrity can all contribute to elevated safety risks if not thoroughly characterized during development.
BTC-500: High-Fidelity Testing for Large-Format Cells
H.E.L’s BTC-500 is specifically designed to evaluate large-format battery cells and modules under adiabatic conditions, enabling precise assessment of thermal behavior in worst-case scenarios.
In testing the 790Ah cell, BTC-500 enabled:
- Determination of thermal runaway trigger temperature and critical initiation conditions
- Measurement of heat release rate and total heat output
- Analysis of thermal runaway propagation pathways and timing
- Gas sampling and compositional analysis of evolved gases
The system also integrates electrical and mechanical abuse testing capabilities, including overcharge, over-discharge, short circuit, puncture, crush, and impact testing—providing a comprehensive view of potential failure mechanisms.
Enabling Safer System Design
The data generated through BTC-500 testing supports battery developers and system integrators in designing safer energy storage systems. Insights into thermal behavior and gas evolution are essential for developing effective thermal management strategies, early warning systems, and module-level containment solutions.
As energy storage systems become larger and more widely deployed, safety is increasingly linked to long-term performance, reliability, and overall project value.
Supporting the Next Generation of Energy Storage
With the successful completion of thermal runaway testing on the 790Ah cell, H.E.L continues to support the advancement of high-capacity battery technologies through robust, data-driven safety testing.
H.E.L’s BTC series, including the BTC-130 and BTC-500, is widely used across the battery industry for cell-level screening, module-level propagation studies, and validation testing under real-world and extreme conditions.
As the industry moves into the 700+Ah era, reliable safety data will play a critical role in enabling the next generation of energy storage deployment.
