First off, it’s important to note that the release of these first-generation cells doesn’t suddenly mean they’ll be finding their way into an EV. The process is far more reserved and fundamentally sensible from a long-term viability perspective: prove to tier one EV makers that both the technology and production line works, then up-scale from there.
Dr Doron Myersdorf told us: “These cells are first-generation units and will generally be used as samples for our potential partners – who are mostly in the EV space. We want to demonstrate the capability and the technological achievements in our production line, using metalloids – such as germanium – in the first-gen cells. These are the first ever production line (rather than lab-built) batteries that can actually charge in five minutes.
“We don’t expect them to be used or generate business from things like mobile devices, scooters or drones, although we have demonstrated these in the past. Our goal is double-down on the EV market and later this year to demonstrate larger cells using our second-generation technology.”
The cells themselves are small at just 1Ah each. They don’t need to be big, however; Dr Mysersdorf made it clear to us that the purpose is not commercialisation at this stage, just proof of concept and StoreDot’s mass production capability – facilitated by its tech partners in China.
“The samples themselves could be used but it’s just a technology stepping stone, and for us this is a way of moving onto the second-generation technology and applying it to the EV market,” he said. There are also commercial reasons why these first production cells are being used in such a limited way.
These first-generation cells are comparatively expensive because we use Germanium, which is an expensive metalloid, in place of graphite . Our goal is to be at the same cost as a traditional lithium-ion battery in future.”
Whilst StoreDot’s first-generation cells are essentially a proof of concept not only in terms of technology, but also production, the second-generation cells are designed for use in EVs. Part of this is being facilitated by working with Daimler – currently StoreDot’s EV partner.
“We do have Daimler as an investor but so far there is no specific model that we are designing for. We are waiting for the prototyping of our gen-two cell for that. At the moment, Daimler is working within the testing of the first-gen cells.”
Dr Myersdorf told us that StoreDot is in discussions with other EV makers but at the moment no deals or agreements have been signed. In the meantime, that desire to get the groundwork in place – which we alluded to above – is the dominating factor for StoreDot.
“We are going to leverage all the effort we have put in over the last few years with our supply chain and stabilised production line to start transitioning to the gen-two cells – which is based on silicon. By the end of 2021, our aim is to have the production line ready for gen-two (the EV-specific battery).”
In terms of capabilities, we saw what StoreDot’s chemistry was able to achieve when we attended the five-minute charging demonstration. Our previous Q&A with Doron is also worth a read, but extreme fast charging (XFC) looks extremely promising.
Dr Myserdorf told us: “The industry average is 3-3.5 miles per minute so we want to show the possibility of XFC with the performance of gen two. The batteries themselves offer a similar energy density to regular lithium-ion batteries, but the real advantage is that we can give a full charge in – using the example of a 50kWh Nissan LEAF – ten minutes. This is equivalent to 20 miles per minute of charging.”
Of course, it’s possible to point at extreme fast charging technology that is already available as being able to get near these speeds. At 350kW an EV might claw back 20 miles per minute, but it can only do this for a short period of time while the battery is in the charging sweet spot. Above certain charge levels, the speed is backed off significantly, as anyone who has used an ultra-rapid charger and monitored its input will attest to.
“With current claims of – say – 350kW max charging, that input is only achieved for a short period, reaffirmed Dr Myserdorf. “With our technology we are able to deliver a power like that for a sustained timeframe – even 350kW. It’s the whole premise of moving from graphite to metalloids – to allow for a high charge rate for the full charge time.”
High charging speeds do impact battery longevity, but StoreDot is working on this, too.
“In terms of battery life, gen-one batteries have a shorter lifespan of 1000 charge cycles and gen-two is currently running at 800 cycles, but this will improve over time as we move towards a commercial product. It’s worth noting that the circa 1500 cycles a traditional graphite battery might be rated for are at slow charging speeds, whereas our charging cycle numbers are all at fast charge speeds. We want to reach 1500 cycles for the commercialised product.”
Dr Myersdorf told us that StoreDot’s end goal is to deliver an EV ownership experience where charging is a similar experience to putting fuel in a traditional ICE-powered car. This essentially knocks down one of the major barriers to adoption for a lot of people: charging times.
Of course, there are other schools of thought, such as that of how most people will charge most of the time at sub-50kW speeds. Our recent chat with Dunstan Power of UK charging specialists, Versinetic, stated as much and various studies show that around 75 per cent of EV charging is at slow speeds. However, there’s also an increasing need and requirement to provide charging solutions to those who don’t have a home charger. This is where having battery tech like StoreDot starts making sense.
It will certainly be interesting to see how StoreDot’s batteries will enter the market in the next five years or so, and how dependent they will be on other factors – such as the charging stations and grid being upgraded and the technology becoming easier and cheaper to manufacturer – to enable ultra-fast charging.