With so much data now available in the Battery Pack Database it is interesting to look at Cell to Pack Mass Ratio by Chemistry and Format. Note that for this analysis we have excluded all of the BESS packs as they tend to not be as mass sensitive as mobile applications.
The fixed lines showing the mass ratios 65%, 75% and 85%. When starting an initial concept design it is useful to initially estimate the battery pack gravimetric energy density as 65% of the cell gravimetric density. This is a reasonable starting target for NMC. However, with LFP we see that 70% would be a better starting position.
• LFP (green) tracks closest to the 75% efficiency line and above, reflecting the growing adoption of cell-to-pack and blade architectures that eliminate module mass; LFP’s flat, stable chemistry also reduces the thermal management mass penalty.
• NMC/NMCA (blue) shows the widest spread and a shallower trend line. The overhead of more intensive thermal management for higher-nickel cells pulls the pack/cell ratio down relative to LFP at comparable cell energy density.
• NCA (orange) clusters at the high end of cell Wh/kg (230–280 Wh/kg) but with moderate pack efficiency, consistent with the cylindrical format requiring significant module structure and thermal management.
• The divergence between LFP and NMC trend lines is meaningful: at 200 Wh/kg cell level, an LFP pack achieves approximately 10–15 Wh/kg more at pack level than an equivalent NMC pack, driven by architecture rather than chemistry alone.
• Blade (orange) sits highest on the efficiency scale. BYD’s blade architecture is specifically designed to serve a structural function within the pack, eliminating the module layer and maximising the proportion of pack mass that is active material
• Cylindrical and prismatic (red and blue) are broadly similar in median efficiency despite very different construction; the cylindrical format’s winding efficiency is offset by the dead space between cells, while prismatic’s flat faces allow tight packing but require more structural support
• Pouch (green) shows the widest spread, appearing in everything from small PHEV packs with modest packaging efficiency to highly optimised BEV platforms; the format’s flexibility in shape means pack efficiency is strongly dependent on how well the vehicle architecture accommodates the cell dimensions
• The blade trend line is steeper than the others. As blade cell energy density increases, the pack efficiency benefit compounds, because the fixed overhead of the pack enclosure becomes a smaller fraction of total mass relative to the high cell energy content and push towards larger packs.
This post has been built based on the support of and sponsorship from: illumion, Custom Power, Quarto Technical Services, Eatron Technologies and About:Energy
As we said at the start, the Battery Pack Database is available for a small fee and allows you to analyse it in any way that you want, eg: filtering by pack voltage, cell make, etc.
Cell Chemistry and Format vs Application
It is really interesting to look at cell chemistry and format vs application, because in principle there is nothing stopping us from applying any chemistry or cell format to any application. In practice, however, the market has converged on some clear preferences. Here we have taken the Battery Pack Database and looked at this question with regards to packs in production.