The Mercedes-AMG GT XX is a 1MW of motor power EV concept car that showcases the future. As per the EQXX it maybe shows us the Mercedes thinking on battery design.
The high-voltage battery in the CONCEPT AMG GT XX is a completely new development. It benefits from all the experience from the AMG ONE and Formula 1® as well as the knowledge of the best engineers from Mercedes-Benz and Mercedes-AMG. The High Performance Electric Battery (HP.EB) delivers a high power output with exceptional repeatability, guaranteeing the vehicle’s outstanding overall performance. This is paired with rapid energy absorption and high power density.
Contributing to the high system performance are three main aspects: new battery cell developments, direct cooling of the cells and high voltage. The charging performance likewise sets new benchmarks – again due to direct cooling. This pairs with optimised thermal management of the cells and power lines during charging. The CONCEPT AMG GT XX achieves a very high average charging power of more than 850 kW at 1000 ampere over a wide range of the charging curve. This makes charging almost as fast as refuelling.
Mercedes
Looking at these limited details:
- Pack
- 800V battery
- Energy = 114kWh
- Immersion cooling
- Power
- Charging = 850kW
- 249 miles of range in five minutes [1]
- Peak discharge ~1100kW (1000kW motor power)
- Charging = 850kW
- Power
- Structure
- Pack to Chassis
The high voltage battery is centrally integrated into the structure of the electric skateboard platform. Its protective housing encases the cell modules, all switch components and the Battery Management System (BMS), which is likewise an exclusive in-house development by AMG. Defined lateral load paths combine high torsional rigidity with low weight and form the basis for a high level of crash safety.
The battery housing is part of the vehicle structure and integrated into the crash concept. Battery, high voltage (HV) cables and further HV components are configured and secured to fulfill Mercedes‑Benz’s high safety requirements.
Mercedes [4]
- Cells
- cylindrical
- tall and skinny – “shortening the distance from the core to the casing and allowing heat to dissipate much more rapidly under load.” [3]
- case – “laser welded aluminium, so they’re lighter than steel and have better conductivity” [3]
- >3,000 cells in the pack
- Chemistry = NCMA [4]
- Gravimetric energy density = 300 Wh/kg [4]
- Volumetric energy density = 740 Wh/l
- Tabless [4]
- cylindrical
This post has been built based on the support of and sponsorship from: Quarto Technical Services, Eatron Technologies and About:Energy
A further innovation is the optimized operating window. The full-tab cells underwent detailed measurement and testing in advance using a special reference electrode and core temperature sensors. The data gathered was implemented in the software for the battery management system. This enables better modelling of cell behavior and thus a significant increase of charging power at higher temperatures.
Mercedes [4]
Can-Cap Welding of Structural 4680 Aluminium Cell Can
It has been shown that high strength aluminium grades like Speira ION Cell 3-CS boost the structural performance. On the other hand, higher strength materials enable down-gauging of the can wall while maintaining the same maximum pressure and hence, provide significant lightweighting potential. The impact of strength can be estimated using Barlow’s and Lame’s equation considering Tresca yield criterion.
- Modules
- plastic
- coolant flows through coolant channels in the modules, which are optimized for equal cooling of all the cells. A special piping system ensures even distribution of the cooling oil [4]
- cooled using dielectric oil
The charging power sets the continuous rate capability of the battery pack. However, 850kW is an ~8C rate and hence even with dielectric cooling this probably also uses some of the pack heat capacity as headroom.
Based on the pack having 114kWh (not sure if this is usable or total) and >3000 cells it puts the energy of each cell at around 38Wh and hence a larger cell than the previous Mercedes HPB batteries that use the 21700 format.