At the 21st Auto Shanghai exhibition, Eve Energy showcased its latest technological developments, with its large cylindrical battery emerging as a focal point.
Jiang Jibing, vice president of Eve Energy and head of its battery system research institute, introduced the large cylindrical battery as the “optimal solution” for new energy vehicles (NEVs). He detailed the battery’s advantages through three key factors: standardization, adaptability, and structural integrity.
First, Jiang emphasized standardization. He explained that large cylindrical batteries streamline manufacturing processes by addressing a major challenge in China’s NEV sector: mismatched production capacities. Unlike prismatic batteries, large cylindrical designs deliver nearly ten times the production efficiency. Their uniformity in system components and module assembly allows them to function as standardized automotive parts, enhancing overall manufacturing efficiency.
Second, Jiang discussed “in-situ upgrading.” As NEV product cycles shorten to 12–18 months, maintaining fixed physical dimensions while supporting various chemical compositions becomes critical. The large cylindrical batteries accommodate multiple chemistries—including lithium iron phosphate (LFP), lithium manganese iron phosphate (LMX), and nickel cobalt manganese lithium (NCM)—providing flexibility in adjusting energy density, range, charging times, and output. This adaptability significantly cuts R&D timelines to as little as three to six months and can lower development costs by up to 80%.
Third, Jiang introduced the “zero expansion” feature. Thanks to their cylindrical structure and choice of materials, these batteries maintain consistent dimensions over their lifecycle. This property reduces the complexity of mechanical stress management and simplifies the overall battery system design, making the in-situ upgrade model more viable.
Jiang also stressed the battery’s inherent safety features. Eve Energy integrates a 1,500-megapascal thermal solid steel shield, aerospace-grade fiberglass rated at 3,500 MPa, and full-domain foaming technology. Together, these features allow the battery to absorb up to 1,000 joules of collision energy, exceeding China’s new national safety standard by a factor of 6.6.
Achieving mass production of large cylindrical batteries posed several technical challenges. Jiang outlined four key breakthroughs:
- Low-temperature performance: After four years of R&D, Eve Energy introduced low-resistance pathways and system insulation heating technology. Their batteries now support 25-minute fast charging at temperatures as low as minus 30 degrees Celsius, while improving low-temperature driving range by 20%.
- Precision in assembly: Each battery system contains approximately 700–800 individual cells, cooled with a double-sided liquid system and connected by intricate electrical circuits. Eve Energy achieved vertical tolerance within 200 micrometers and horizontal positional accuracy within 250 micrometers, ensuring stable thermal management and mechanical durability.
- Weld reliability: Each battery pack has over 1,500 weld points critical for electrical continuity. Eve Energy reports achieving weld depth precision within 80 micrometers, securing consistent and reliable connections throughout the battery system.
- Structural reinforcement: The cylindrical form factor naturally offers five times the strength of prismatic batteries. Full-domain foaming fills all gaps, increasing the battery pack’s torsional rigidity beyond 15,000 newton-meters. This enhancement allows vehicle chassis to achieve torsional stiffness exceeding 50,000 micrometers. The company tightly controlled temperature during the foaming process at three degrees Celsius and used a 1:4 foaming ratio to maximize material density and structural integrity.
On the IP front, Jiang noted that Eve Energy has filed more than 2,300 patent applications across 15 countries, reportedly making it the global leader in patent filings for large cylindrical batteries.
Commercially, Eve Energy has ramped up production over the past 15 months, supplying battery systems for more than 32,000 vehicles, maintaining a safety record of zero incidents across an average mileage exceeding 210,000 kilometers per vehicle.
According to announcements at Auto Shanghai, Eve Energy’s large cylindrical batteries have been adopted by several automakers, including Chang’an Automobile, FAW Group, BMW, Nio, and JAC Motors. The company anticipates further expansion in production and adoption in the near future.