When it comes to energy storage systems, choosing the right cell is one of the most critical decisions you’ll make. Whether you’re developing a high-performance electric vehicle (EV), an eVTOL (Electric Vertical Takeoff and Landing) aircraft or an industrial backup power system, the cell you select will directly impact the performance, safety, longevity and cost of your system.
At Energy Storage Specialists Ltd (ESS), we’ve worked across a variety of sectors to help clients select the most suitable cells for their specific needs. In this post, we’ll walk you through the key factors to consider when choosing a cell for your application.
1. Understand Your Application Requirements
Before diving into cell specifications, it’s essential to understand the specific requirements of your application. Different applications have different needs, which means the cell selection process will vary significantly between industries.
For example:
- EV require cells that offer high energy density for long range, fast charging capabilities and reliable performance in a wide temperature range.
- eVTOLs demand lightweight, high-energy and high power density cells to maximise payload capacity while maintaining flight time.
- Grid storage applications need cells that provide long cycle life and stability over many years of use.
Knowing your application’s primary objectives, whether it’s range, cycle life, cost, safety or something else, will help narrow down your options.
2. Key Factors to Consider
Once you have a clear understanding of your application’s needs, here are the core factors to consider when selecting the right battery cell:
a. Energy Density (Wh/kg or Wh/L)
Energy density refers to the amount of energy a battery can store relative to its weight (Wh/kg) or volume (Wh/L). The higher the energy density, the more energy you can store in a smaller and lighter package. This is particularly crucial in applications like eVTOLs or EV where space and weight are at a premium.
b. Power Density (W/kg)
Power density measures the cell’s ability to deliver power quickly, which is important for high-performance applications like motorsport. If your system requires fast acceleration or high burst power, look for cells with high power density, even if it sacrifices a bit of energy density.
c. Cycle Life
Cycle life refers to how many charge and discharge cycles a battery can undergo before its capacity starts to degrade. In industrial and grid storage applications, long cycle life is often the top priority, as these systems are expected to last for many years.
d. Voltage and Capacity
Different applications will require different voltages and capacities. A high-voltage cell may be needed for systems that require more power (to decrease current output), while higher capacity is essential for storing larger amounts of energy. Be sure to match the voltage & capacity with your system’s requirements and design.
e. Safety
Safety should always be a priority, especially in applications that will be exposed to extreme conditions, high temperatures or mechanical stresses. Look for cells that come with built-in safety features like:
- Temperature protection
- Over-voltage and under-voltage protection
- Short-circuit protection
As a minimum, consider cells which have UL and IEC certifications, these would have undergone a series of tests to show their robustness in case of abuse.
f. Cost vs. Performance
Budget constraints are always a factor but it’s essential to balance cost with performance. Higher-quality cells with better energy density and longer life may have a higher upfront cost, but they can save money over time due to fewer replacements and better overall performance.
Also, there are different grade of cells, so be sure to ask what cell grade you are purchasing as different grades means difference performance electrical and safety!
3. Types of Battery Cells
There are various battery chemistries and cell formats to consider, each offering its own set of advantages and trade-offs. The most commonly used chemistries in energy storage today include NMC, LFP and NCA. However, emerging options like solid-state and LMFP are gaining traction and are gradually making their way into commercial systems.
The ideal chemistry for your application will depend on your specific requirements for energy density, power output, safety and cost.
4. Test and Evaluate Your Selection
While your cell supplier will provide a wealth of information, we strongly recommend conducting some of the testing yourself. This not only validates the data you receive but also gives you the confidence to engage in informed discussions if discrepancies arise.
5. Partner with Experts
Selecting the right battery cell isn’t just about picking the best specifications – it’s about understanding your system as a whole. Partnering with a battery design expert can help you navigate the complex landscape of cell selection and ensure your battery system delivers the performance and reliability you need.
At ESS, we provide expert consultancy for cell selection, helping clients choose the best cells for everything from eVTOL aircraft to grid storage solutions. Our deep understanding of cell performance, system integration, and validation ensures that your battery system will perform optimally for years to come.
Conclusion
Choosing the right battery cell for your application is a complex process, but with the right approach, it can lead to outstanding performance and long-term reliability. By considering factors like energy density, cycle life, voltage and safety, you can make an informed decision that aligns with your project’s specific needs.
If you’re ready to take the next step in battery system design, contact us today for expert guidance. Our team is here to help you select and integrate the perfect battery solution for your application.
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