Computer-Aided Design and Analysis 63 subject. However, as mentioned previously several of the cell manufacturers have developed their own tools for doing this type of analysis and many others have developed tools that they use internally but do not distribute publicly. It is possible to use some of the battery sizing models that IEEE organization has developed. IEEE standard number 485-2010 offers a set of guidelines for sizing a lead acid battery pack for stationary energy storage applications (IEEE, 2014) and IEE standard number 1115-2000 offers a similar methodology for sizing a nickel–cadmium battery for stationary applications (IEEE, 2014).
One battery sizing tool that is based on the IEEE standards is Alcad’s “BaSiCs online Battery Sizing and Configuration System” (ALCAD, 2010). The software is free to download for a trial period. However, the tool was designed for lead acid type industrial applications which means that it will not always be a great fit for a lithium-ion application but with some manipulation and understanding of the standard it may do generally the same job for lithium-ion. The biggest challenge with trying to adopt the lead acid sizing model to the lithium-ion battery application is the difference in load models.
With the lead acid sizing model, it is typically possible to quickly add up all of the loads and times to determine the needed power. With a lithium-ion battery, the operation cycle tends to be much less static and will vary greatly throughout its operational profile. The lead acid models used in the IEEE standards are also very data-intensive when trying to convert them for lithium-ion use, requiring quite a lot of testing to be done in order to ensure the accuracy of the tool. There is also certainly quite a bit of lithium-ion testing that must be done, but for the sizing of the battery these data are typically part of the standard characterization process.
Design Guidelines and Best Practices Many analytical software packages are being modified and/or developed to assist the engineering team in the areas of thermal, mechanical, and electrical performance analysis Analytical engineering packages enable rapid and frequent design updates prior to hardware being built Computational fluid dynamics analytical software packages are used for thermal analysis of battery pack designs and systems Finite element analysis can be used for physics-based thermal, electromagnetic, and mechanical analysis, but is most frequently used in analyzing the stress and vibration of the mechanical designs No industry standard battery sizing tools currently exist for lithium-ion-based energy storage systems IEEE standards for lead acid and nickel–cadmium batteries may be able to be used as surrogates Many battery companies have developed their own battery sizing tools