Back in 2021, we wrote a post about the fundamentals of battery technology and its place in the eVTOL and AAM markets. Now that three years have passed, it’s perhaps time to revisit this fundamental area of technology to see how things have changed.
So, what’s changed in the AAM battery tech space? Well, at the core, not much. All-electric aircraft need a lot of power, particularly for vertical launches. Existing battery technology can handle this, but its energy density is one of the major reasons why a lot of AAMs have a fairly short range.
In turn, this means longer range simply requires more batteries. For example, Archer Aviation’s recent eVTOL will hold six 800V battery backs to power its 12 engines. This will contribute a lot of weight to the aircraft, although these batteries do offer a range of around 160km.
The bottom line is that existing battery technology can serve a purpose in AAM, but the weight and power density are definitely limiting factors. Lithium-ion batteries are the current focus for AAMs being tested, but these will most certainly be usurped by superior technology as soon as it’s available.
Perhaps one of the most generative avenues of technology for AAM is solid-state batteries. The technology isn’t new, but recent developments in manufacturing and the discovery of new materials have made the concept more viable than ever.
Solid-state batteries allow for greater energy density with less weight, as well as higher safety standards. For example, the solid electrolytes are non-flammable when heated, offering a major advantage for certification in AAMs. There are plenty of hurdles to overcome with solid-state batteries, but they offer the biggest potential for revolutionising all kinds of battery technology.
Elsewhere, Toyota has released details about new automotive batteries it plans to produce in the coming years. Granted, these aren’t related to AAM, but they demonstrate the avenues being investigated in battery tech. It plans to release three kinds of lithium-ion batteries with different range and performance options, while also developing and releasing its own solid-state battery.
However, the most viable option for the near future is definitely hybrid AAMs. Granted, this doesn’t relate directly to battery technology, but it offers a different route to overcoming the limitations of current lithium-ion batteries. Hydrogen electric engines play a similar role but use hydrogen cells to generate electricity.
The Honda hybrid eVTOL offers a decent comparison. Its range will be 400km – more than twice the range of the Archer Aviation eVTOL above. While standard hybrids have the obvious disadvantage of including a traditional petrol engine, they arguably offer the best compromise between range and convenience that can be achieved with current technology.
While the fundamentals of battery technology haven’t changed much in the last three years, the AAM market is in a completely different place. Hybrid eVTOLs have risen in popularity, and solid-state battery technology promises some major advancements in the next few years. The impact this will have on AAMs will be significant, so it’ll be interesting to see it in action.
