Sodium Ion Cell Manufacturing Process

A look at the Sodium Ion Cell Manufacturing Process, but perhaps more usefully a look at the differences compared to the lithium based cell manufacturing processes.

Note: this is a work in progress as we gather information and knowledge. Hence some sections are empty because we do not know, not because there are no differences. Please do contribute if you can.

1. Electrode Manufacturing

Step 1 – Mixing

Step 2 – Coating

Challenges

Opportunities

  • Both electrodes in a sodium ion cell are aluminium. This reduces cost over copper in the lithium ion anode electrode and brings a volume element to reducing electrode cost further.

Step 3 – Drying

Step 4 – Calendering

2. Cell Assembly

Step 5 – Slitting

Step 6 – Final Drying

Step 7 – Cutting

Challenges

Opportunities

  • Sodium ion cells are a lot easier to recycle and hence the material recovery in production should also form a closed loop reducing costs.

Step 8 – Winding or Stacking

The Separator materials are the same as in a lithium ion cell.

Step 9 – Terminal Welding

Challenges

Opportunities

  • As both electrodes are aluminium it then one process design and optimisation can be used for both tabs.

Step 10 – Canning or Enclosing

This post has been built based on the support and sponsorship from: AVANT Future MobilityQuarto Technical ServicesTAE Power Solutionsh.e.l group and The Limiting Factor. 

3. Cell Finishing

Step 11 – Filling

The Electrolyte is a sodium salt & solvent, except sodium salt, the solvent is not very different from that used in a lithium ion cell.

Challenges

Opportunities

  • The sodium based electrolyte has a higher flashpoint and hence improved handling opportunities and increased vacuum at the filling stage.

Step 12 – Formation & Sealing

Step 13 – Ageing

Challenges

Opportunities

  • Sodium ion cells are much safer than lithium ion cells and unlikely to go into thermal runaway. Hence possible to significantly reduce the fire detection and protection at this stage. Hence opportunity to reduce equipment costs and area required at end of line for this facility.

Step 14 Final Control Checks

Challenges

  • Being able to ship Sodium ion cells at 0V improves safety in transport, but does bring a challenge for the cell integrator to test the incoming cells. A more complete handshake on cell data may be required to ease this risk to the integrator.

Opportunities

  • Sodium Ion cells can be shipped at 0V, hence improving safety. This also means that the 30% energy left in a lithium-ion cell for shipping can be removed in a sodium ion cell.

Note: this is a work in progress as we gather information and knowledge. Hence some sections are empty because we do not know, not because there are no differences. Please do contribute if you can.

References

  1. Sodium-ion Batteries: Inexpensive and Sustainable Energy Storage, Faraday Insights 11

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