The requirement is to maximise hydrogen storage while minimising tank weight, volume and cost.
For Arcola Energy’s powertrain platform, and for heavy duty FCEVs in general, the current standard for is 350 bar tanks, either Type 3 or Type 4. To maximise hydrogen storage these tanks are generally large: 2-3m in length and with an external diameter of at least 400mm.
Key metrics are
- Gravimetric capacity in wt% (kgH2/kg%)
- Volumetric capacity in kgH2/L (external volume)
As an example, for a benchmark Type 4 tank
- Gravimetric capacity - 8.0wt%
- Volumetric capacity - 0.017 kgH2/L
- Cost - < £1000/kgH2
- Certified for 5000 fill cycles
In the longer term, technology improvements may allow use of 500bar and 700bar tanks for heavy duty vehicles, and liquid or cryo-compressed hydrogen storage are also future possibilities.
Certification to relevant automotive standards (EC79:2009 or GTR No.13) is assumed. Cycle life is important with 5000 fill cycles being currently the industry standard (~15 years for daily refuelling).
The survey asked about interest and capabilities for current technology and the R&D requirements to develop improvements on the current state of the art.