Structural vs. Swappable Battery Packs

Here at Guidehouse Insights, battery pack swapping has been an ongoing topic of discussion among the transportation team for several years. At first glance, battery swapping seems like an incredibly obvious idea but it has only recently begun to get any real traction for EVs. However, thanks to Tesla’s latest changes to the Model Y, we may be headed toward a bifurcation of EV architectural concepts. 

The swapping concept is hardly new, with Better Place having tried and failed with the idea a decade ago. Better Place’s approach wasn’t fundamentally wrong, but it was too early, pre-dating any significant EV adoption, and the company ran out of money. A few months after Better Place went bankrupt, Tesla made a big show of demonstrating battery swap capability on the Model S, but only ever built one swap station in central California. That effort was widely viewed as nothing more than a proof of concept to earn extra zero emission vehicle credits from California for supporting swapping, but without ever really pursuing it. By 2016, that lone swap station had also been shuttered. 

Take Two for Swapping

In contrast, Nio began opening swap stations in China in 2018 and now has more than 1,000 locations. The upstart automaker just announced it has completed its 10 millionth swap and its network is doing more than 30,000 swaps per day. Other Chinese OEMs are also planning to pursue swapping as an alternative to fast charging. 

Swapping has become particularly successful in the micromobility market where small scooter and bike batteries can be easily swapped at curbside kiosks installed all around cities. Gogoro has been particularly successful in partnering with micromobility manufacturers and sharing operators across Asia. 

Swapping also holds promise for fleet operations in urban areas where exceptionally long range is less important than maximizing uptime of the vehicles. However, other battery architectural optimizations run contrary to swap benefits.

Going Structural

At its 2020 battery day event, Tesla announced a new larger cylindrical cell format known as 4680 with plans to integrate it into a new structural battery pack. Tesla and its partners have yet to be able scale production of 4680 cells and some of the internal changes. But the automaker is building some Model Ys at its new Texas factory with whatever cells it can scrape together into structural packs. The team at benchmarking firm Munro and Associates acquired one of these early build examples and has begun a teardown. 

While most modern EVs are designed with the pack providing some of the body’s structural integrity, Tesla has taken this design to a whole new level. Until now, EVs retained a floor as part of the body with the pack sitting below the floor and fastened around the perimeter. In a recent video showing the removal and examination of the pack, the Munro engineers realized that the Tesla pack actually is the floor. As the body was lifted away from the pack, the seats and center console remained attached to the pack. 

This approach has the potential to lead to significant cost and weight reduction for future EVs, although it’s unlikely to be compatible with swapping. That could in turn lead to either longer range from similar battery capacity or the same range with a smaller, less costly battery pack. For average consumers, this may prove to be far more valuable than the ability to swap batteries in a vehicle they can’t afford to buy in the first place. 

What this really demonstrates is that there is no single ideal tool for every task. Vehicle purchasers will need to think about their needs and get the vehicle that best satisfies them.