Porsche Macan PPE

An early look at the Porsche Macan PPE based EV. Porsche released a number of images and a video of the platform [1]. The PPE platform is being developed by Audi and shared across a number of vehicle lines, PPE standing for Premium Platform Electric.

Porsche Macan EV PPE Platform

Metrics

  • Energy Density
    • Gravimetric = 175 Wh/kg
  • Power Density
    • Peak = 868 W10s/kg
    • Continuous= 474 Wcont/kg
  • Usable Energy = 97 kWh (total ~100 kWh)
    • SoC Window = 0.97
  • Nominal Voltage = 662 V
    • Maximum Voltage = 765 V
  • Nominal Capacity = 152 Ah
  • Configuration = 180s 1p
  • Power = 495 kW10s
  • Pack Mass = 570 kg
Porsche Macan EV PPE Platform

Packaging & Structure

We immediately see the power cables running down one side of the battery pack. Interesting that these are essentially between the body and pack, hence likely to get crushed and electrically shorted in a side impact.

There appear to be 10 through bolt fixings, 5 each side of the centre.

In the image with the power electronics on top of the battery you can see a substantial box section that runs across the back of the battery pack, the rear subframe front mounts pick up on this structure.

At the front od the pack the rear mounts of the front subframe clearly align with the fore-aft internal structural beams of the battery (more easily seen in the video [1] from where these images were clipped).

There are 3 fore-aft beams in the pack. With 12 modules in total it suggests that this is a 4 across x 3 lengthways arrangement of modules.

Module

  • 12 modules in the pack
  • 15 Cells/module

Cell

  • Chemistry = NMC811
  • Format = Prismatic
  • Nominal voltage = 3.68 V
  • Nominal capacity = 152 Ah
  • Nominal energy = 559 Wh

This post has been built based on the support and sponsorship from: Eatron TechnologiesAbout:EnergyAVANT Future MobilityQuarto Technical ServicesTAE Power Solutions and The Limiting Factor. 

Power Electronics

A diecast aluminium box sits on the top of the battery pack and under the second row seats.

This contains:

  • on-board AC charger
  • high-voltage heater
  • DC/DC converter

Charging

  • FC peak power = 270 kW
  • 5 to 80% SoC <25 minutes

If the station is using 400-volt technology, the all-electric Macan uses ‘bank charging’ for the first time, whereby corresponding high-voltage switches (gates) are automatically switched in the battery before the actual charging process begins. This effectively splits the 800-volt battery into two batteries with a nominal voltage of 400 volts each that can be charged in parallel on one 400-volt charging station without an additional HV booster. If necessary, the states of charge of the two battery halves are first aligned before they are charged together.

Porsche Media [1]

The split pack approach to allow 400V charging is a move away from the fixed 800V pack in the Porsche Taycan that used a DC-DC to enable 400V charging. This is a significant change in architecture and the split pack approach brings additional failure modes. Hence, this is a surprising change and it would be good to understand the issues face with the Taycan and hence this change in approach.

Two main issues with split charging:

  1. as soon as aging happens, the half packs end up having different internal resistances and capacity of the cells, which in practice means that when charging the pack with a given current, the current will not be split in half, i.e. there will be asymmetry on the two half packs in terms of state of charge, heating and so on, especially when doing fast charging.
  2. contactors: keep in mind that it is not only a matter of turning ON/OFF some switches, which also adds failure modes to be diagnosed, and potential new short circuit failures in case the relays gets stuck transitioning from one configuration to another (series / parallel); for this 2nd point, there is also the issue of monitoring two half packs voltages, and currents, so the sensors have to be doubled (4 current sensors instead of 2, and many more HV sensing points).

This is not a bad solution, just that it adds a number of engineering challenges.

References:

  1. Porsche fine-tunes E-Performance for future series models, Porsche Media
  2. Electric Macan: Porsche’s outlook on the PPE, electrive
  3. We Check Out Porsche’s New PPE Platform And Upcoming Macan BEV, InsideEVs

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