Discover how cylindrical battery cells are manufactured step-by-step. Learn about the production process, quality control, and why these cells power your devices efficiently.
How Cylindrical Battery Cells Are Made
Ever wondered how the battery cells powering your tools, e-bikes, or portable devices are made? You're looking at one of the most fascinating manufacturing processes in the energy industry. As a leading battery cell manufacturer, we at Highstar have been perfecting this process for over 30 years, and we're excited to share what goes on behind the scenes.
Whether you're sourcing batteries for your products or just curious about battery technology, understanding how cylindrical cells are made will help you make better decisions. Let's dive into this process together!
What Makes Cylindrical Cells Different
You've probably seen cylindrical batteries everywhere - from your TV remote to power tools. But what sets them apart from other battery types? The magic lies in their unique design and manufacturing approach.
Cylindrical cells get their name from their round shape, which isn't just for looks. This design gives them incredible structural strength and makes them perfect for high-drain applications. Think about it - when you're using a power drill or riding an e-bike, you need batteries that can handle vibration and deliver consistent power. That's exactly what cylindrical cells do best.
At Highstar, our cylindrical sodium ion cell technology takes this even further. We've developed models like the NaCR3370-5ER and NaCR46145-20ER that deliver up to 130Wh/kg energy density with an impressive 8C discharge rate. This means you get more power when you need it most.
Raw Materials and Preparation
Before we can start building a battery cell, we need the right ingredients. Just like baking a cake, the quality of your raw materials determines the final product. Here's what goes into making a cylindrical cell:
The main components include:
● Cathode materials (positive electrode)
● Anode materials (negative electrode)
● Separator (keeps electrodes apart)
● Electrolyte (allows ion flow)
● Current collectors (aluminum and copper foils)
● Steel casing (the outer shell)
The preparation phase is where precision matters most. We start by mixing the active materials with binders and solvents to create a slurry. This mixture needs to be just right - too thick and it won't coat properly, too thin and you lose energy density. Our automated systems maintain the perfect consistency, checking viscosity every few minutes.
For our sodium-ion cells, we use specially formulated materials that give us advantages like better temperature performance (-40°C to 80°C) and enhanced safety. As one industry expert recently noted, "The shift to sodium-ion technology is revolutionizing how we think about battery safety and sustainability."
The Core Manufacturing Steps
Now we get to the heart of cylindrical cell production. The manufacturing process follows a carefully orchestrated sequence that transforms raw materials into powerful energy storage devices.
First, we coat the electrode materials onto thin metal foils. The cathode mixture goes on aluminum foil, while the anode coating lands on copper foil. These coated foils pass through massive ovens where temperatures reach up to 150°C, evaporating solvents and leaving behind the active materials. Picture a giant printing press, but instead of ink, we're laying down the future of energy storage.
Next comes calendering - we compress these coated foils between heavy rollers to achieve the perfect thickness and density. This step is like ironing clothes, but with tons of pressure. The result? Electrodes with uniform thickness and optimal porosity for ion movement. Every micrometer counts here, as thickness variations can lead to uneven charging and reduced battery life.
The cutting phase transforms these large sheets into precise strips. Our laser cutting systems slice through the materials with accuracy down to 0.1mm. These strips will soon be wound into the cylindrical shape that gives these batteries their name.
Winding Process Explained
Here's where the magic really happens. The winding process is what transforms flat electrode strips into the cylindrical cells you recognize. If you've ever rolled up a sleeping bag, you've got the basic idea - but imagine doing it with microscopic precision.
We start by aligning the cathode, separator, and anode strips in a specific pattern. The separator - a thin, porous plastic film - keeps the electrodes from touching while allowing ions to pass through. Think of it as a referee keeping two players apart while the game continues. Our winding machines operate at speeds up to 10 meters per minute, maintaining perfect tension throughout.
The winding pattern typically follows this structure:
| Layer | Material | Function |
| 1 | Separator | Prevents short circuits |
| 2 | Cathode | Positive electrode |
| 3 | Separator | Additional protection |
| 4 | Anode | Negative electrode |
The wound "jelly roll" (yes, that's the technical term!) needs to fit perfectly inside the steel casing. Too loose and you waste space; too tight and you risk damaging the materials. Our automated systems adjust tension in real-time, ensuring each cell meets exact specifications.
Assembly and Sealing Methods
With our jelly roll ready, it's time for assembly. This phase transforms the wound electrodes into a sealed, functional battery cell. We insert the roll into a steel casing - typically 18650 (18mm diameter, 65mm length) or 21700 sizes for larger capacity needs.
Before sealing, we attach current collector tabs to connect the electrodes to the cell's terminals. These tiny metal strips carry all the power your device needs, so their welding must be flawless. We use ultrasonic welding techniques that create molecular bonds without adding heat that could damage the sensitive materials.
The electrolyte injection comes next. We fill each cell with precisely measured electrolyte under vacuum conditions. This liquid is the highway for ions traveling between electrodes during charging and discharging. Too little and the cell won't perform; too much and you risk leakage. Our filling stations measure down to 0.01 grams.
Sealing the cell requires both mechanical crimping and laser welding. The top cap includes safety features like pressure release vents and current interrupt devices. As we like to say, "Safety isn't just built in - it's sealed in."
Formation and Testing Phase
You might think we're done, but the cells aren't ready yet. The formation process is like teaching a battery how to be a battery. We charge and discharge each cell multiple times under controlled conditions, activating the materials and forming protective layers on the electrodes.
During formation, cells go through several cycles at different rates and temperatures. This process can take 3-7 days, depending on the chemistry. We monitor voltage, capacity, and internal resistance throughout. Cells that don't meet our standards get recycled - no exceptions.
Our testing protocol includes:
● Capacity verification at multiple discharge rates
● Internal resistance measurements
● Self-discharge testing over weeks
● Safety tests including overcharge and nail penetration
● Temperature cycling from -40°C to 60°C
The data from these tests doesn't just pass or fail cells - it helps us continuously improve our manufacturing process. Every batch teaches us something new about optimizing performance and reliability.
Quality Control Standards
Quality control isn't just a final step - it's woven throughout our entire manufacturing process. From raw material inspection to final packaging, we maintain strict standards that exceed industry requirements.
We use both automated vision systems and human inspectors to catch defects. Our AI-powered cameras can spot coating inconsistencies invisible to the human eye, while experienced technicians perform physical inspections at critical points. This dual approach catches 99.9% of potential issues before cells leave our facility.
Documentation matters too. Each cell carries a unique identifier linking it to complete production data - materials batch numbers, equipment used, test results, even the humidity level during manufacturing. If a customer ever has a question, we can trace that cell's entire history in minutes.
Our commitment to quality has earned us certifications including UL, IEC, CE, and BIS standards. But more importantly, it's earned us the trust of customers worldwide who depend on our batteries for critical applications.
Why Choose Highstar's Cylindrical Cells
After walking through this complex manufacturing process, you might wonder what makes Highstar different. It's not just our three decades of experience or our state-of-the-art facilities - it's our complete approach to battery solutions.
Our sodium ion battery solution represents the next generation of cylindrical cell technology. With advantages like lower raw material costs, enhanced safety, and excellent low-temperature performance, these cells are perfect for applications from telecom backup power to electric vehicles.
We don't just make cells - we provide complete battery pack solutions tailored to your specific needs. Our engineering team works with you to optimize performance, whether you need high-discharge rates for power tools or long cycle life for energy storage solutions.
What sets us apart:
● Customization capability - from cell chemistry to pack design
● Proven reliability - over 4.5 billion cells shipped globally
● Innovation leadership - first to commercialize sodium-ion cylindrical cells
● Complete solutions - from cells to BMS to final integration
Making Your Battery Decision
Understanding how cylindrical cells are made helps you appreciate the technology powering our daily lives. From the precise coating of electrodes to the careful formation process, every step contributes to the final product's performance and reliability.
Whether you're developing new products or upgrading existing ones, choosing the right battery cell supplier makes all the difference. At Highstar, we combine manufacturing excellence with innovative chemistry to deliver cells that exceed expectations.
Ready to explore how our cylindrical cells can power your next project? Our team is here to help you navigate options and find the perfect solution for your needs. Because at the end of the day, we're not just manufacturing batteries - we're powering possibilities.
Compare sodium ion and lithium ion batteries side-by-side. Learn the real differences in cost, performance, safety, and applications to make the best choice for your needs.
Discover how cylindrical battery cells are manufactured step-by-step. Learn about the production process, quality control, and why these cells power your devices efficiently.
From 11 to 13 June 2025, the 18th (SNEC 2025) International Solar Photovoltaic and Intelligent Energy Exhibition (Shanghai) Conference and Exhibition was grandly held in Shanghai National Convention and Exhibition Centre. In this highly anticipated industry top event,China's new energy industry forerunner and innovator -- Highstar, with its energy storage full series of products and five core scenarios of solutions brilliant debut, attracted a large number of industry experts, customers and the media came to communicate and visit. It has become one of the focuses of the exhibition.
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