Selecting the right cell for the job: effective cell testing and qualification for real world applications

Summary:

As lithium-ion batteries have become more reliable, smaller, lighter, and cheaper, they have been incorporated in many contemporary technologies and products. As a result, there has been a dramatic increase in the number of batteries manufactured today, creating seemingly endless choices when original equipment manufacturers (OEMs) select a battery for any given device. While battery vendors provide specification sheets, this information does not provide a full picture of battery quality nor of the expected performance in every application. This inevitably leads to the question of how to select a battery manufacturer and how to qualify the cell for a particular application.

Exponent is a multi-disciplinary engineering and scientific consulting firm that brings together more than 90 different disciplines to solve engineering, science, regulatory, and business issues facing our clients. One of the focuses of our London office and laboratories is in battery technology, including (among other battery-related services): preliminary hazards analysis, cell design review and cell testing. Exponent’s experienced engineers and scientists can design unique application specific test protocols that are tailored to evaluate a cell’s performance in its operating environment and help interpret the significance of the results. We commonly conduct a variety of high-level performance and reliability tests on cells to help our customers qualify battery manufacturers.

In this poster we outline some of our procedures for: how to choose the correct battery for the job taking into consideration vendor, cell chemistry and cell design; qualification of batteries using tools and methodologies that go beyond the standards to gain a deeper understanding of possible performance or safety issues that may appear in the final product; we also take a look at accelerated cell testing, relevant to the application of cells in a given product or environment; and finally, how stress-failure mode testing can give insight, not only into cell limitations, but also be used to root out weaknesses and inspire better cell design. Several case studies will demonstrate the value of these techniques and how issues can arise when more in-depth analysis is not performed during qualification testing.