MG MSP Platform Battery

[sammoj]

Hi All

Just out of interest tonight I decided to have a chat with Google Gemini AI about the MGS5. I thought this response about the NMC 64kWh battery was interesting and worth sharing.

J

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The 64kWh NMC (Nickel Manganese Cobalt) battery in the MG S5 EV is part of MG’s third-generation battery technology, built on the Modular Scalable Platform (MSP). It incorporates several advanced safety systems specifically designed to manage the higher energy density and thermal characteristics of NMC chemistry.

1. Zero Thermal Runaway Technology​

The most critical safety feature of this battery is its Zero Thermal Runaway design. This system is engineered to prevent a "domino effect" if a single cell fails:

• Passive Isolation: The pack uses high-performance thermal insulation between cells to block heat transfer.
• Rapid Heat Dissipation: If a cell enters an abnormal state, the system is designed to vent heat and gases quickly through a dedicated pressure-relief system, ensuring that open flames do not spread to adjacent cells or the cabin.

2. "One Pack" Protection & Ultra-Thin Design​

The battery utilizes an innovative Horizontal Cell Design, making the pack only 110mm thick. This contributes to safety in two ways:

• Low Center of Gravity: By sitting lower in the chassis (a 490mm center of gravity), the battery reduces the risk of vehicle rollover during high-speed maneuvers.
• Structural Integrity: The battery is encased in a reinforced high-strength steel frame that acts as a structural member of the car. In crash tests, this frame is designed to absorb side-impact energy, protecting the internal cells from deformation.

3. Advanced Thermal Management​

Because NMC batteries are more sensitive to temperature than LFP alternatives, the S5 uses a more sophisticated active cooling system:

• Liquid Cooling Loop: A dedicated cooling circuit maintains the battery within its optimal temperature window (typically 25°C to 35°C), reducing the risk of overheating during rapid DC charging at 139kW.
• Real-Time Monitoring: The Battery Management System (BMS) monitors the voltage and temperature of every cell group 24/7, even when the car is parked, and can trigger cooling if it detects an abnormal temperature rise.

4. Electrical & Crash Safety​

• High-Voltage Disconnect: In the event of an airbag deployment or a significant impact, the car’s pyrotechnic fuses (pyrofuses) instantly "fire," physically severing the high-voltage connection between the battery and the rest of the vehicle to prevent electric shocks or post-crash fires.
• IP67/IP69K Rating: The battery housing is dust-tight and sealed against high-pressure water jets and submersion, ensuring electrical safety during flooding or deep-water wading.

5. Safety Ratings​

These battery safety features contributed to the MG S5 EV achieving a 5-star Euro NCAP safety rating in 2025, with a 90% score for Adult Occupant Protection. The testing specifically verified that the battery remained stable and the cabin was protected after severe frontal and side-pole impacts.


Note for NMC Owners: To maintain these safety margins over the long term, it is recommended to keep the battery between 20% and 80% charge for daily use, as leaving NMC batteries at 100% for long periods in high heat can increase internal pressure and stress on the cells.

 

[MG Clive]

I must admit to not fully trusting AI, but that looks like good information, thanks @sammoj

 

[TimothyN]

I don't know about Gemini, but ChatGPT has two modes. I have always used Thinking Mode since it was introduced a few months ago, and it does seem to make it hugely more accurate and less likely to "fantasise".

 

[sammoj]

Gemini is similar, this is a pro account so always in thinking mode.

I have no reason to believe that any of the information is incorrect but feel free to compare it with ChatGPT or even give it to ChatGPT to validate.

 

[Ian Key]

I must admit to not fully trusting AI, but that looks like good information, thanks @sammoj

I'm the same. AI's sources are only as reliable as the information it has scanned.

The final note about leaving it at 100% in warm weather makes sense and implies that leaving it full charge occasionally won't have any noticeable detriment to the battery.

I wonder if @Miles Roberts CG has access to the technical data and can verify the information?

 

[sammoj]

Interesting reactions to the use of AI. I asked Gemini to reveal its sources for its analysis so here is a revised text with sources which you can go and check should you wish to do so. The majority of these appear to be MG or NCAP documentation however one is a dealer in Ireland which could be more suspect as a source simply because it isn't first hand.

I won't post any more information from AI based on the reaction from people.

J

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Based on recent official product launches, technical brochures, and 2025 safety ratings, the analysis of the MG S5 EV’s battery technology is largely accurate. The MG S5 is built on the Modular Scalable Platform (MSP) and utilizes the "One Pack" battery architecture originally debuted in the MG4.


Below is the validation of the specific claims with supporting sources.

1. Zero Thermal Runaway Technology​

• Validation: Confirmed. MG’s "One Pack" battery system, utilized in the MSP platform, features a "Zero Thermal Runaway" design.
  
  
  
• Technical Details: The system employs an "adaptive pressure control system" and rapid heat diversion pathways to prevent thermal propagation between cells.
  
  
  
• Sources: MG Innovation Technical Portal; MG Motor Europe Press Kit (2025).

2. "One Pack" Protection & Ultra-Thin Design​

• Validation: Confirmed. * Thickness: The battery is officially documented as being 110mm thick, making it one of the thinnest in its class.
  
  
  • Horizontal Cell Design: This is a hallmark of the MSP platform, allowing for more cabin space and a lower center of gravity.
    
    
    
  • Structural Integrity: The battery pack is integrated into the chassis, which features "Ultra High Strength Steel" and "Advanced High Strength Steel" to protect against side impacts.
• Sources: MG S5 EV Official Brochure (April 2025); MG Motor UK "Innovation" technical specifications.

3. Advanced Thermal Management​

• Validation: Confirmed.
  • Charging & Cooling: The 64kWh NCM (Nickel Cobalt Manganese) battery supports 139kW DC rapid charging (10-80% in approximately 28 minutes).
    
    
    
  • Active Monitoring: The Battery Management System (BMS) includes real-time monitoring and an active liquid cooling loop to maintain temperatures during high-speed charging.
• Sources: MG Motor Ireland MGS5 Technical Specs; John Clark MG Group "MGS5 EV Range & Charging" data.

4. Electrical & Crash Safety​

• Validation: Confirmed.
  • Pyrofuses: Like most modern MSP-based MGs, the S5 uses high-voltage disconnects triggered by impact sensors.
  • IP Ratings: The battery housing meets the IP67/IP69K standards for dust and high-pressure water protection.
• Sources: MGS5 EV Owner’s Manual (2025); MG Global Safety Standards Documentation.

5. 2025 Safety Ratings​

• Validation: Confirmed. * Score: The MG S5 EV achieved a 5-star Euro NCAP rating in 2025.
  
  
  • Adult Protection: It specifically scored 90% for Adult Occupant Protection, mirroring the high performance of the MG4 on the same platform.
    
    
• Sources: Euro NCAP Official Results (2025); MG Motor UK Media Centre "New MGS5 EV achieves highest safety rating" (May 2025).
  
  

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Summary Table: MG S5 64kWh Battery Specs​

Feature	Specification
Chemistry	NCM (Nickel Cobalt Manganese)
Platform	Modular Scalable Platform (MSP)
Thickness	110mm
Max Charging	139kW DC
Safety Rating	5-Star Euro NCAP (2025)

 

[Miles Roberts CG]

I'm the same. AI's sources are only as reliable as the information it has scanned.

The final note about leaving it at 100% in warm weather makes sense and implies that leaving it full charge occasionally won't have any noticeable detriment to the battery.

I wonder if @Miles Roberts CG has access to the technical data and can verify the information?

The information as stated certainly backs up what I have been told by MG UK in various training courses, and have read in technical bulletins from HQ.

 

[Hallix73]

I suppose on those facts then charging to 100% in winter low temps wont damage cells as much in hot climates?

 

[Ian Key]

I suppose on those facts then charging to 100% in winter low temps wont damage cells as much in hot climates?

That's how I read it especially as I have just done a 100% balance charge as I was expecting to take out an elderly friend for lunch and decrease the amount of charge. Unfortunately he had to cancel due to a gut infection so I won't be decreasing the amount of charge as quickly as intended.