When electric cars were released, it seemed like we were well on our way to revolutionising transportation and combating fumes that drive climate change. However, while rare in practice, exploding batteries and flaming EVs get a lot of media attention. That means EV batteries have to be extra safe to ensure that people aren’t afraid of investing in a new electric car.1 It’s mainly a perception issue, but it’s a genuine concern. 

 

the Gemini Battery pack by Our Next Energy, or ONE. This battery divides the work between a lithium iron phosphate (LFP) cell and a newer, “anode-free” lithium ion manganese oxide battery (LiMnO) cell. The LFP half of the battery is “min-maxed’” for fast charging and short bursts of city driving, while the LiMnO half is slow, steady and energy dense, which is perfect for long road trips. 

 

An LFP essentially comes with all the benefits that have made the lithium ion the industry standard without cobalt, which is both expensive and difficult to obtain. As a result, LFPs tend to be safer, less toxic, and longer lived than most of their cousins. LiMnOs are a type of secondary battery or energy accumulator. Like LFP batteries, their chemistry uses more common elements and are generally cheaper and less toxic. They’re also thermally stable, which is important for safety. However, their chemistry means you don’t want to charge or discharge them very often, as they can quickly build up dendrites. Dendrites are pesky metal spikes that slowly build up during charging and discharging and, over time, can threaten to puncture the battery.

Together, these batteries cover each other’s weaknesses. The LFP cell’s thermal stability, long life, and high specific power make them charge quickly and stand up to the hard life of an EV. However, LFP batteries tend to have a low specific energy, meaning they aren’t as energy dense as other types. 

 

The company’s battery formulation uses manganese-rich cathodes and far less cobalt than comparable batteries . Though ONE claims they’re going to ditch cobalt entirely, they haven’t yet. It also uses 20% less lithium, 60% less graphite, and 75% less nickel relative to other batteries. Cobalt and nickel are rare in our current supply chain, which significantly drives up the price of EV batteries…and therefore EVs. So, because the LFP side of the battery is mainly made up of abundant iron, you end up with a significantly cheaper EV.

 

Batteries that incorporate cobalt are also more vulnerable to thermal runaway. So, by minimising the cobalt in their design, ONE is also minimising the chance of a fire. This is because the cobalt-oxygen (Co-O) bond is much weaker than the phosphorus-oxygen (P-O) bond. When a battery overheats, the Co-O bond is easily broken, releasing flammable oxygen quickly, feeding the fire. The P-O bond is stronger and doesn’t release the oxygen as quickly.

 

Gemini’s patented “skip-cell” safety architecture is also another big contributor to reducing battery overheating and thermal runaway. In a roundabout way, this actually helps the Gemini’s performance, as space that would normally be used by fire mitigation boxes in other batteries can now be packed with more cells, which helps with the weight problem that all EVs face.

 

How does this battery actually perform? Does it actually work? The answer is looking like a resounding “yes.” In a test drive on December 17th, 2021, ONE put their battery to the test, strapping it into a Tesla Model S. It managed to drive for 752 miles on a single charge. That’s nearly double the Model S’s current range of around 400 miles.

 

 For most people, that equates to about 150 miles of driving from a single charge on the LFP alone. After that point, it switches to the anode-free cell to charge the LFP cell, another trick borrowed from standard hybrid cars. Perhaps we are approaching a future where electric cars are no longer a statement of wealth.