EXPLAINED: How EV Battery Packs Are Assembled Feat. MG Windsor Pro

When MG Motor India announced its arrival into the Indian market, it took over the erstwhile GM manufacturing plant, located at Halol, Gujarat. Over the years, the brand has put increased focus on electric vehicles with models such as the ZS EV, Comet EV, Windsor EV, M9 and Cyberster, and has even established a battery assembly plant recently. We got the opportunity to visit this facility, which is responsible for assembling batteries for the Windsor Pro and Comet. Here is a quick walkthrough of the entire process in pictures:

Step 1: Unboxing

This first step in assembling the battery is laying out insulation material in the battery tray. Post which the coolant piping is carefully laid out. If you were wondering, EVs with liquid cooled battery packs too need to use coolant in order to optimize battery health and control temperatures, and are crucial to maintaining a long lifespan.

Step 2: Laying The Cells

Once the insulation material is laid out, the next step is laying out the cells in a carefully organised manner. Given that the capacity of the Windsor Pro’s battery is 52.9kWh and each cell has the capacity of 540Wh, there are a total of 97 cells in every battery pack. 

Step 3: Laser Welding

After laying the cells, metal plates are laid out over terminals to connect each cell terminal in a series configuration. After this, the pack goes into the laser welding terminal where an automated high-precision robot ensures microscopic precision in welding the plates.

Step 4: Connecting Terminals

Once the cell terminals are welded, they are connected in a series configuration with high voltage wiring harnesses. At this stage, the end connectors are also attached.

Step 5: Charging And Discharging Test

After the battery is connected and ready, it goes into a dust-proof Charging And Discharging area wherein each pack is given a full charge cycle with a rapid full charge followed by a quick drop to a fully discharged state to monitor performance and identify any faults. This step, MG tells us, is crucial to determine the final road-worthiness and is the ultimate test for the cell quality.

Step 6: Sealing The Battery Pack

Post the Charging And Discharging Test, the battery goes to the final assembly station. Here, a special IP67-compliant gasket is added to prevent dust and water ingress before sealing the entire battery pack with special tools. 

Step 7: Final Assembly Line

Now that the battery pack is ready, it is stored and then transported in batches to the Final Assembly Line, where it finally meets the bodyshell. MG Motor uses a high level of automation in their plant and the battery pack is brought into the work area by an automated robot. 

Step 8: Marriage

The term ‘Marriage’ is used to describe the process of bringing together the engine and transmission with the body of the car. In this case, the Windsor Pro being an EV, it is the battery pack and electric motor which are raised into the bodyshell ready to be mounted. Once raised, the engineers affix the high-voltage connectors to the electric motor and battery before securing the underbody.

Step 9: Final Rollout

Post the ‘marriage’, the bodyshell continues to proceed on the assembly line to add components such as doors, dashboard, trims, seats, bumpers, lights etc, before finally being rolled out at the end of the assembly line. It is now finally ready to be transported to its new home!

ZigSays…

EVs have always been looked at with a lens of skepticism when it comes to safety. However, after a deep-dive into the rigid standards and protocols followed by carmakers in the assembly processes, there is no doubt in our minds that EVs are just as safe and re-assuring to drive as internal combustion engines. 

What do you think of this process? Let us know in the comments below!