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VW e-Golf - No Thermal Battery Management System?


VW decided not to offer a Liquid Cooled Thermal Battery Management with the new e-Golf.

It seems VW is going the cheaper route entering the EV segment unlike the systems of the Model S(same Panasonic batteries), Focus Electric and Volt(where recent consumer reports over 146k miles and ZERO capacity loss).

The lack of a Thermal Management System for the battery pack in the e-Golf, will give the Focus Electric a clear advantage when the e-Golf comes to the US later this year, and around the world.

The Leaf with it's battery also with no thermal battery management system, was tested and lost over 25% of it's capacity at 40k miles. Which is why Nissan now has a separate Battery Capacity Warranty, where they will replace the battery with another refurbished battery at 20% loss within 60k miles. Along with their never ending $99/mo Battery Lease after 60K miles when capacity stops below a useable range.

In a recent study by the Idaho National Laboratory, published by insideevs where they were testing the effects of L2 and DC Fast charging on the Nissan Leaf's battery with no thermal protection, and found that capacity loss was over 25% at just 40k miles.

Below is a graph that shows 4 different Leaf vehicles L2 vs DC Fast Charging.



Comparing these results with the thermal protected battery packs of the Model S, Focus Electric and Volt that go over 140k miles with ZERO battery capacity loss.

It sounds like VW, late to the EV game, is going the cheap route and down the same path as Nissan.

VW made it clear that that battery pack longevity of charge capacity was clearly not a focus in this quote from their own Press Release:

".....the engineering goal was to develop a highly efficient system as opposed to one that focused on charge-time or capacity (like some of our competitors). "

But what's telling, and a clear contradiction to their justification, is that the Golf GTE plug-in hybrid will have a liquid cooled battery management system. Using the same battery cells that amazingly don't need thermal protection in the e-Golf.

And something else that's a bit odd, is how VW justifies this decision by essentially blaming it on their 'engineers' as of they are separate from VW:

"Our engineers tell us that the e-Golf has passed various long-term engineering evaluation milestones in desert temperatures and cold weather climates, without the necessity of a cooling system."


Below is the VW Press Release where they try and explain their reasoning:

Generally speaking, regarding the system, it's important to note that the e-Golf was designed with efficiency in mind. The battery pack utilizes ultra-efficient lithium-ion cells that deliver 25Ah per cell with an energy density of 59Wh per lb. The pack is comprised of 264 cells, packaged into 27 modules (of either 6 or 12 cells) delivering 323 volts and weighing in at 700 lbs. As it relates to battery temperature, VW has developed a Battery Management Unit with an intelligent thermal control that allows the pack to remain within an optimal temperature window, helping to maintain performance and range in a variety of temperatures. This system allows the e-Golf to operate, even in more extreme temperatures, without the need of a cooling system and without dramatic impacts in performance based on testing.

In terms of the battery pack, the engineering goal was to develop a highly efficient system as opposed to one that focused on charge-time or capacity (like some of our competitors). In partnership with Panasonic, VW utilizes a lithium-ion cells designed for gentle charge and de-charge during use which helps to reduce heat and energy consumption often associated with cells designed for rapid charging and de-charging. Our engineers refer to them as "marathon cells." Additionally, without a cooling system weight savings are achieved which aides in overall efficiency of the vehicle. Due to the efficiencies achieved, minimal waste heat is created during operation (i.e. during fast charging) and is quickly directed by the battery metal structure into the chassis, away from the battery, helping to prevent extreme temperature conditions inside the pack.

Our engineers tell us that the e-Golf has passed various long-term engineering evaluation milestones in desert temperatures and cold weather climates, without the necessity of a cooling system.
 
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