from chemistry to pack
There is a battery pack density fundamental limit and that is the cell density. Obviously, but how close can we get to that limit? The following plot shows the pack gravimetric energy density plotted versus the cell gravimetric density. Added to this dataset is the fundamental limit. If we calculate the ratio of this we … Read more
Battery pack Ragone plot is power density versus energy density. There are a number of key battery metrics and this one is great to see where a design sits on the Power vs Energy Density Curve. Note that the power is the peak power of the pack available for 10s. You could also plot the … Read more
The Nissan Leaf is perhaps the iconic original OEM BEV. Therefore, interesting to see how it performs against the competition over the years. The pack gravimetric density versus year of introduction is an interesting plot. Arguably the energy density should be outstanding as these packs are passively cooled. However, they are also conservative with respect … Read more
The cell to pack mass ratio is a simple metric to calculate and gives you an idea as to the efficiency of your pack design. This is simply the total mass of the cells divided by the mass of the complete battery pack expressed as a percentage. The larger the percentage the better: An interesting … Read more
When benchmarking battery packs the intention is to create a standard list of data and then a list of references. This form will post will form the standard list that we will use going forward and hence we need to get this 90% complete before we start. The first thing to look at when benchmarking … Read more
Cell Gravimetric Energy Density with the units Wh/kg is a key cell metric. The optimum metric is a high Wh/kg. Hence: High nominal voltage High Ah capacity Low mass Perhaps the simplest of the battery metrics as the capacity of the cell is fairly easy to measure and the mass is just a set of … Read more