Posted on April 22, 2018 by Charles Morris
The Tesla Model 3 and Chevy Bolt are two very different vehicles, but both are mid-priced EVs that feature a range of over 250 miles. Their battery packs are similar in capacity (60 kWh for the Bolt, around 50 kWh for the Standard Model 3 and 75 kWh for the Long Range version), but in terms of their design, they are very different. A recent article in InsideEVs discusses the surprisingly large differences between the Chevy Bolt and Tesla Model 3 packs.
In a pair of extended videos from Weber Auto, Professor John Kelly disassembles a Bolt battery pack, and puts it back together again, revealing its inner workings in great depth.
No similarly detailed teardown videos for Model 3 have yet appeared on our screens, but InsideEVs’ George Bower offers some meaty technical details about Tesla’s new pack, and how it differs from GM’s product.
Bower finds that the Bolt pack is simpler to assemble, but the Tesla pack has it beat in terms of energy density. The rival packs employ quite different cooling systems. Tesla’s features a ribbon-shaped cooling tube that snakes between the cells. This technique is also used in Model S, but in the Model 3, the individual cells are attached to the cooling ribbon, apparently with glue. The Bolt pack is much simpler - the individual prismatic cells simply sit on a cooling plate, separated from it by a thermal mat.
Another large difference between the Tesla and GM packs is their specific energy, at least at the module level - some painstaking calculations based on the weight of each module indicate that the Model 3 modules pack considerably more energy per kg. However, Bower points out that “Tesla’s battery chemistry is much more flammable than GM’s and it requires more armor to deflect foreign objects.” Therefore, Tesla’s case is likely heavier, which would negate part of the advantage in energy density.