What is Battery Cell Validation and Why is it Important?

Although the term “battery” immediately calls to mind a household AA for most people, modern batteries range in complexity from that single-cell AA to large assemblies that may include hundreds of cells and a sophisticated battery management system. When manufacturers include multiple cells in a battery, they need to be sure that all the individual cells will perform and age in a balanced way and that all the cells have comparable safety characteristics, otherwise the battery pack may fail prematurely or even cause a safety hazard. Testing labs assess individual cells to compare their characteristics in a process called cell validation.

Cell validation ensures the quality and performance of different cells and ensures their compatibility within a battery pack or system. Battery cells, such as lithium-ion cells, are typically manufactured in large quantities, and although high-quality cells tend to be very consistent, not all cells are identical in terms of their characteristics and performance capabilities. Cell validation helps to identify and select cells that meet the required specifications, ensuring optimal performance, safety, and reliability of the battery pack. During cell validation, various tests and measurements are conducted on individual battery cells to evaluate their electrical, chemical, and physical properties. These tests often include:

Capacity testing: Cells are discharged and charged to measure their energy storage capacity, which indicates the amount of electrical charge they can store and deliver.

Voltage testing: The voltage behavior of cells is monitored under different load conditions to assess their performance and stability.

Internal resistance measurement: The internal resistance of cells is measured to determine their ability to deliver power efficiently and to identify any abnormalities or variations.

Cycle life testing: Cells are subjected to repeated charge and discharge cycles to evaluate their durability and lifespan. This test helps determine the number of cycles a cell can undergo before its performance significantly deteriorates.

Safety testing: Cells undergo safety tests to assess their behavior under extreme conditions, such as high temperatures or overcharging. This ensures they meet safety standards and mitigates the risk of thermal runaway or other hazardous situations.

Environmental testing: Cells may be subjected to environmental stress tests, including temperature and humidity variations, to evaluate their performance under different operating conditions.

Cell validation is crucial in battery manufacturing and assembly processes, especially for high-stakes applications like communications, safety, or medical devices. The performance of the battery has a direct impact on the functionality and longevity of the device or systems using it. Poor cell quality or a large quality variation could lead to a shorter life of the product, an insufficient power supply, or even a dangerous product failure.

Many new manufacturers are entering the energy storage market and learning by trial and error as they rush to meet increased global demand for battery-powered products. Cell validation makes it possible to better discern the cell or battery pack's performance, set realistic expectations, and identify the most appropriate battery for specific needs.  By validating individual cells, manufacturers can select and match cells with similar characteristics to optimize the overall performance and efficiency of the battery pack.

Cell validation is a precise science. Testing needs to be done by professionals with the right educational background and hands-on experience to select appropriate test methods and interpret the results accurately. If you have questions about cell validation or any other aspect of battery testing, reach out to our battery testing experts today. Element has the largest battery testing capacity in North America, and unparalleled expertise in battery safety, performance, abuse testing, and much more.