Xiaomi SU7 Max Battery

The launch Xiaomi SU7 Max battery is made by CATL and appears to be the Qilin approach with Xiaomi integrating this as a Cell to Body (CTB) design.

As per a lot of the speculation in the press, this does look like a competitor to the Porsche Taycan.

Most of the data in this article is from Xiaomi’s own press-release, but more will get added as we dig deeper.

Metrics

  • Volumetric density 3% improvement (but compared to what?)
  • battery integration efficiency = 77.8%
  • Energy capacity = 101 kWh
  • Peak power = 495 kW
  • 800V architecture
  • Configuration = 165s (33 rows of 5 cells/row)
  • Cell
    • CATL
    • Energy ~ 612Wh
    • Capacity ~ 168Ah

The pack has 33 rows of cells and there appears to be 5 cell/row. That gives a total of 165 cells. In the Xiaomi article [1] they say that 165 pieces of aerogel are used to protect the cells. Hence this appears to add up.

The only issue is that 165s gives a nominal pack voltage of ~600V and not the claimed 800V architecture.

The beam at the front of the pack is very substantial, suggesting that this supports the cell expansion forces.

  • The sides of the battery cells feature 165 pieces of aerogel insulation material, capable of resisting temperatures up to 1000°C.

It would be interesting to see how well the aerogel survives the expansion forces of the cell and hence whether they are a robust thermal barrier towards the later stages of the battery lifetime.

At the rear of the pack we see another substantial cross-beam. This is also braced across theopen box sections at the rear. Our assumption is that these open boxes house the BMS and maybe the HV distribution system.

This post has been built based on the support and sponsorship from: Eatron TechnologiesAbout:EnergyAVANT Future MobilityQuarto Technical Services and TAE Power Solutions.

The battery does have a substantial pod on the top that would be housed under the second-row seats.

Dimensions

Height = 120mm

  • A 14-layer robust physical protection system includes
    • 3 layers of top support
    • 3 layers of side protection
    • 8 layers of bottom protection.

Cooling

  • Dual sided
  • water cooling solution
  • cooling area = 7.8m²
Section through CATL QILIN

BMS

Xiaomi give a few details around the Battery Management System:

  • ASIL-D = highest functional safety level
  • 3 independent thermal runaway monitors and alarms
  • around-the-clock early warning system

First look at this pack and it appears to be worth having another look, we just need a few more parameters. The safety in terms of physical barriers and control system is a very strong approach. It would be great to understand what the 3 independent thermal runaway monitors are.

References

  1. Xiaomi Unveils Five Core Automotive Technologies and Debuts Xiaomi SU7, Completing the Human x Car x Home Smart Ecosystem, Xiaomi Global
  2. Xiaomi details SU7 and SU7 Max EVs, ArenaEV

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