VDA 355 Module Energy Density: Wh/kg and Wh/l Explained
Short answer: The VDA 355 modules compared here reach 209-219 Wh/kg and 440-447 Wh/l at module level, depending on cell configuration. The MEB 590 modules reach 212-216 Wh/kg and 448-456 Wh/l. Both are module-level values; pack-level density is always lower once housing, cooling, BMS and cabling are included.
Energy density is one of the first figures an engineer reaches for when comparing battery module formats. It is also one of the most frequently misread, because a module-level figure and a pack-level figure are not the same thing, and datasheets are not always clear about which one they state. This article works through the calculation for VDA 355 and MEB 590 modules, shows how to verify a published figure from first principles, and explains what the numbers actually determine in a pack design.
What energy density means at module level
A battery module's gravimetric energy density (Wh/kg) is its usable energy divided by its mass. Its volumetric energy density (Wh/l) is its usable energy divided by the volume of its outer envelope, not the net volume of the cells inside. Using the envelope volume is the only fair basis for comparison, because the envelope is what occupies space in a pack.
The distinction between module level and pack level matters because every structural component added around the modules (the pack housing, thermal management plates or channels, the battery management system, interconnect busbars and cabling, and the mechanical fasteners) adds mass and volume without adding energy. Pack-level density is therefore always lower than the module-level figure. By how much depends on pack architecture; no single correction factor applies across all designs.
How to calculate Wh/kg and Wh/l from a datasheet
The calculation requires three inputs: nominal energy in kWh (or Ah times nominal voltage), total module mass in kg, and the outer envelope dimensions in mm.
Step 1: energy in Wh. Use the nominal energy stated on the datasheet. If only capacity and voltage are given, multiply them: for the 2P6S, 22.02 V x 116 Ah = 2,554 Wh, which matches the stated 2.55 kWh.
Step 2: Wh/kg. divide the module energy in Wh by mass in kg.
Step 3: envelope volume in litres. multiply length x width x height in mm, then divide by 1,000,000 to convert mm³ to litres.
Step 4: Wh/l. divide module energy in Wh by volume in litres.
Where a datasheet states a Wh/kg figure, you can verify it yourself. If your result differs slightly from the published value, the difference is almost always rounding in the mass or in the energy figure. The example below illustrates this.
Worked examples: VDA 355 and MEB 590
VDA 355 1P4S NMC
A 1P4S configuration places one cell per parallel group and four groups in series. At a rated energy of 2.59 kWh and a module mass of 11.85 kg:
- Wh/kg: 2,590 / 11.85 = 219 Wh/kg
- Envelope volume: 355 x 151 x 108 mm = 5,789,340 mm³ = 5.79 litres
- Wh/l: 2,590 / 5.79 = 447 Wh/l
The catalogue lists 214 Wh/kg for this configuration. The difference of about 2 % is most likely the weight basis or the rounding behind the published figure. The practical lesson: always recalculate from the kWh and kg values stated on the specific datasheet, and treat the rounded figure as a guide, not a precision specification.
VDA 355 2P6S NMC
A 2P6S module holds twelve smaller cells instead of the four large cells of the 1P4S, in the same housing.
- Energy: 2.55 kWh; mass: 12.2 kg
- Wh/kg: 2,550 / 12.2 = 209 Wh/kg
- Envelope: 355 x 151 x 108 mm = 5.79 litres (same footprint)
- Wh/l: 2,550 / 5.79 = 440 Wh/l
Energy is almost the same as the 1P4S (2.55 against 2.59 kWh) and the module weighs 0.35 kg more, so Wh/kg is slightly lower.
MEB 590 2P8S NMC
The MEB 590 module has a longer envelope (approximately 590 x 225 x 110 mm) and carries more cells. A 2P8S configuration at 6.66 kWh and 31.4 kg:
- Wh/kg: 6,660 / 31.4 = 212 Wh/kg
- Envelope volume: 590 x 225 x 110 mm = 14,602,500 mm³ = 14.6 litres
- Wh/l: 6,660 / 14.6 = 456 Wh/l
MEB 590 1P12S NMC
A longer module of similar width with a 1P12S NMC configuration at 147 Ah nominal capacity and 44.4 V nominal voltage:
- Energy: 44.4 V x 147 Ah = 6,527 Wh, rounded to 6.53 kWh
- Mass: 30.25 kg
- Wh/kg: 6,530 / 30.25 = 216 Wh/kg
- Envelope (the catalogue also lists a length of 594 mm; check the datasheet): 599 x 225 x 108 mm = 14,555,700 mm³ = 14.56 litres
- Wh/l: 6,530 / 14.56 = 448 Wh/l
For background on the MEB format and how it relates to the VDA 355, see VDA 355 vs MEB 590: which battery module format fits your pack?.
Comparison table
| Module | Configuration | Energy (kWh) | Mass (kg) | Wh/kg | Envelope volume (l) | Wh/l |
|---|---|---|---|---|---|---|
| VDA 355 | 1P4S NMC | 2.59 | 11.85 | 219 | 5.79 | 447 |
| VDA 355 | 2P6S NMC | 2.55 | 12.20 | 209 | 5.79 | 440 |
| MEB 590 | 2P8S NMC | 6.66 | 31.40 | 212 | 14.60 | 456 |
| MEB 590 | 1P12S NMC | 6.53 | 30.25 | 216 | 14.56 | 448 |
All Wh/l values are calculated on the outer envelope of the module, not on net cell volume.
What the numbers tell you, and what they do not
The table shows that, at module level, VDA 355 and MEB 590 configurations sit within a narrow band: roughly 209-219 Wh/kg and 440-456 Wh/l. The spread between the lowest and highest figure in this set is less than 5 % in either dimension.
The practical implication is that format and packaging space drive module selection more than energy density does. If a vehicle or system platform has a defined cavity for VDA 355 modules, the relevant question is how many modules fit and what cell configuration suits the voltage and capacity target, not which module format has the highest Wh/kg. The advantages of the VDA 355 format lie in mechanical interchangeability and supply-chain flexibility, not in a density premium over alternative formats.
Chemistry also plays a role. All four modules in the table use NMC cells; a module with a different chemistry has a different nominal cell voltage and therefore a different energy per module. A full comparison is in LFP vs NMC in a VDA 355 module: chemistry compared.
On module versus pack density: once the modules are integrated into a pack with a structural housing, a thermal management interface, a battery management system and all electrical connections, the pack-level Wh/kg and Wh/l will be lower than any figure in the table above. The magnitude of that reduction depends on the specific pack design and is not a fixed percentage. Engineers should design to module-level figures when selecting modules, then recompute at pack level with the actual housing geometry and component masses.
For context on how module standardisation emerged and what it means for supply chains, the background of the VDA 355 format covers the history of the format and the rationale behind dimensional standardisation.
Frequently asked questions
What is the energy density of a VDA 355 module in Wh/kg?
Depending on cell configuration and chemistry, a VDA 355 module delivers approximately 209-219 Wh/kg at module level. A 2P6S NMC configuration at 2.55 kWh and 12.2 kg gives 209 Wh/kg; a 1P4S NMC configuration at 2.59 kWh and 11.85 kg gives approximately 219 Wh/kg.
How is volumetric energy density (Wh/l) calculated for a battery module?
Divide the module energy in Wh by the volume of the outer envelope in litres. For a VDA 355 module with an envelope of 355 x 151 x 108 mm, the volume is 5.79 litres. A 2.55 kWh module therefore delivers approximately 440 Wh/l. Wh/l is always stated on the envelope, not on net cell volume.
Why does a published Wh/kg figure sometimes differ from a manual calculation?
Small differences, typically a few Wh/kg, arise from rounding in the mass or energy values on the datasheet. Always recalculate from the stated kWh and kg figures to verify, and treat the rounded catalogue figure as indicative rather than precise.
Is pack-level energy density higher or lower than module-level energy density?
Always lower. Housing, thermal management, the battery management system, busbars and cabling add mass and volume without contributing energy. The reduction depends on pack architecture and cannot be stated as a fixed percentage without knowing the specific design.
Do VDA 355 and MEB 590 modules differ significantly in energy density?
At module level, the difference is small: both formats sit in the range of approximately 209-219 Wh/kg and 440-456 Wh/l across the NMC configurations in the table. Format selection is therefore driven by packaging space, voltage requirements and supply-chain considerations rather than by a meaningful density advantage of one format over the other.
Specify the right module for your pack
Review the VDA and MEB battery modules from Avantis Energy or contact Avantis Energy with a technical question about configuration, voltage matching or pack integration.