We often hear about the so-called ‘synergy’ between EVs and energy storage in the home. Not merely the fact that the majority of both applications for storage tend to have a lithium-ion battery-driven heartbeat at their core, but a lot has been made of the fact that the two industries could spur each other on to both lower costs and increased adoption.
Dean Frankel of Lux Research, one of the authors of Crossing the Line: Li-ion Battery Cost Reduction and Its Effect on Vehicles and Stationary Storage, a recent report looking into both industries and the crossover potential between them, told PV Tech Storage:
“There is a very strong relationship between electric vehicles and stationary storage by way of industry scale-up and in turn cost reduction. The largest industry growth driver for batteries will come from electric vehicles which will improve the price-performance of Li-ion cells and in turn the competitiveness of energy storage systems.”
Or, as UK renewable energy expert Ray Noble put it, “…that’s where the motor manufacturers in mass production can drive down the costs very, very, rapidly.”
And beyond the two learning lessons from each other, there could be direct link-ups. As we’ve seen from projects such as this one involving BMW, which seeks to reuse EV batteries by putting them in a grid-scale system to provide grid stability, lithium-ion packs could live an extended ‘second life’.
“What the battery manufacturers are saying is, because of the way that you use a car, you drive, fast, down loads of energy from the battery etcetera, it’s totally different to how you’d use one in a building. It would be slowly charged up and then slowly drained down, and then charged up again. So in effect it could give the batteries a big extended life,” Noble says.
PV Tech Storage spoke with one British company, Future Transport Systems, which describes itself as a team “converging from the automotive, energy and mobility sectors” with a belief that EVs and stationary storage have a great part to play in developing a “smarter grid”.
“Our theory is that you should get as much value out of the battery before it’s reprocessed. The second life battery is defined by 20% degradation, if we can get a few years more use out of it that’s a big gain for everybody really.”
Future Transport Systems (FTS) is starting with a couple of specific examples where this meeting of technologies could make an immediate difference – if R&D activities and trials are successful and funding found. The company’s CEO Matthew Lumsden was involved in the local investment package that brought production of Nissan’s Leaf EV to the northeast area of England where FTS is based.
One project FTS is working on is to reuse EV batteries to “buffer” rapid charging hubs. Lumsden says that seeing the rapid chargers being put in for EVs that required infrastructure upgrades alerted FTS to this possibility.
“We won a DECC (Department of Energy and Climate Change, UK government department) award looking at the viability of using second life EV batteries to provide… ‘software’ specifically for rapid charging. We’ve developed a system which is linked to a PV array, micro-wind and some rapid chargers so that we can test how the various different usage cycles and so on impact on the batteries and how viable that is as a solution,” Lumsden says.
“The second life battery is defined by 20% degradation, if we can get a few years more use out of it that’s a big gain for everybody really.”
At the moment, while lead acid batteries have a well-established chain to recycle as much of the materials as possible, this doesn’t exist in the lithium-ion space. So, steps taken in this area are tentative, but could still make a difference.
Lumsden explains that, as things stand, reprocessing Li-ion batteries, in other words taking them apart to their components and raw materials for reuse, is impractical and costly.
“Our model at the moment, is to use batteries as they are. So not repackaging them and adding additional cost in that. Our units can just communicate with the batteries, we can just put the batteries in and off they go.”
Going forward, Lumsden and others say they would like to see a consideration of a battery’s possible life after ‘death’ come into play from the very beginning of production.
“Some of the people who are looking at reusing second life batteries are taking the packs to pieces, configuring the modules and things. Our view is that unless they are very specifically built for that, that’s a very expensive approach to doing it. So my view is that the best, or a good case scenario shall we say, is that EV batteries are designed with second life application in mind and therefore they can be very cost effectively reintroduced into a static system without the cost of reprocessing.
Where FTS is starting with rapid charging infrastructure, the company is not stopping there and is working on a separate project for Vehicle-to-grid (V2G) applications.
“There are a number of systems in the marketplace looking at vehicles for the home or for buildings. My view is that V2G, or whatever you call it, bi-directional charging, it’s just an absolute inevitability. Because if you look at the value of storage that will be in hundreds to thousands of EVs then it’s huge.”
However, Dean Frankel of Lux has reservations on the ultimate size of a possible ‘second life’ market for EV batteries.
“Used electric vehicle packs may be repurposed for stationary applications, but at best, it will be a market niche.”
Nissan’s programmes to recycle Leaf batteries could see a “large volume of packs” go back to the manufacturer or its partners, Frankel says, “but it remains to be seen how many packs will be deployed and what the value of those packs is to the end customer. Not to mention, the logistical challenges involved in predicting that usable cycle life and energy capacity of the nearly spent battery pack.”
Lumsden agrees with the assessment that it is likely to be a niche, but one that FTS is prepared to carve out and fulfil the potential of. Frankel also agrees that there could definitely be some as-yet unexplored mileage in the V2G and also in the V2H (vehicle-to-home) space, which he again refers to as “niche” but interesting at the same time.
The smart home concept that has been developed and trialled in numerous parts of the world, connecting vehicle to house (and usually also to grid), relies heavily on communication and clever energy management between the car battery and stationary storage installed in the home alongside it.
Like a lot of really neat-sounding concepts, however, the smart home hasn’t taken off and changed the world yet, and neither have EVs, although in the latter case, we do seem to slowly be getting there. Perhaps for a lot of people who weren’t thinking about this until recently, Tesla’s sideways move into stationary storage which was announced recently, could help to join the dots.
Yet at a practical, immediate level, there are things that could be done, if not to persuade the world into the mass adoption of these twin technologies, then at least to make it easier for consumers to think about it, governments to support it and businesses to see a clear case and an opportunity.
In many ways FTS and companies like it are testing the waters of what a future based around distributed generation and smart technologies might look like.