How much does a steel cell housing weigh?

Even though the housing wall for steel cells is only about 0.55 - 0.65 times as thick as it is for aluminum cells (Fig. 2 a)), the density of steel is almost 3 times as large as that of the housing aluminum alloy (Table 1). Therefore, the absolute weight of the housing is in the range of 1.65 - 1.95 times greater for steel cells.

Why is volumetric energy density larger for steel cells?

For this reason the volumetric energy density in Fig. 3 c) and d) is also larger for steel cells when comparing cells with the same dimensions. With the assumptions from this study, a 4680 cell with aluminum housing provides 676.0 Whl −1 while the same cell with steel housing provides 694.8 Whl −1 which is an increase of about 2.8%.

Do aluminum cells have more energy density than nickel plated steel?

Results show that cells with aluminum housings provide slightly less volumetric energy density of 3% - 4% compared to nickel plated steel housings while providing 9% - 11% more gravimetric energy density.

Why does a 4680 have a higher energy density than a steel cell?

However, cells with aluminum housings require larger wall thicknesses compared to steel cells due to less tensile strength of the raw material. For this reason a 4680 with steel housing provides 2.8% more volumetric energy density compared to cells with aluminum housing.

Why do steel cells have a better charging time?

Steel cells however have worse charging time with a larger influence of the diameter due to increased thermal resistance of the housing in axial direction and larger heat generated for one-sided contacting.

What is a reasonable wall thickness?

Based on our testing results 0.25 mm wall thickness for cells with 21 mm diameter and steel housing and 0.425 mm for aluminum housings were identified as reasonable values, which lays well within the middle of the values reported by Lao et al. .