CATL Freevoy

The CATL Freevoy (Xiaoyao) is a Hybrid Battery Pack, that is it has two or more chemistries within the one battery system. In this case they are using lithium ion cells and sodium ion cells.

The news release from CATL [1] is quite difficult to decipher, but they are making a few claims.

• Improved cold temperature performance
  •  discharge at -40℃
  • charging at -30℃
• Increased range through better state of charge (SOC) prediction and it appears they are using the SOC prediction of the sodium ion cells to enhance the accuracy of the SOC prediction of the lithium Ion cells.

The generic OCV curves for Sodium Ion (yellow) show a much steeper change in voltage versus SOC compared to NMC (blue).

Note: these are generic and not the chemistry being used by CATL, but might hint at a direction they are taking.

• Fast charge rate:
  • 280km in 10 minutes in a pack that is capable of delivering 400km
  • this equates to 10 to 80% SOC charge time of 10 minutes
  • pack supports bidirectional grid connection
• Chemistry changes
  • surface modification technology for the cathode material
  • coupled with an innovative high-voltage electrolyte formulation
  • a nano protective layer
    • minimizes side reactions within the active layer
• Improved BMS algorithms
  • 40% improvement in SOC accuracy
• Improved ageing model that is then used to increase the power delivery of the battery pack
• Safety
  • 2^nd generation no thermal diffusion technology
  • smoke and high-voltage active isolation technology
  • defect rate of battery cells at PPB level

The CATL Freevoy pack has already been incorporated into vehicles from:

CATL release battery pack designs on a regular basis and hence we try to keep a list of those releases so we can understand the development cycle.

References

1. CATL Unveils Freevoy Super Hybrid Battery, Heralding a New Era of Sustainable Travel, CATL
2. High Energy Density Technology, CATL