Is repurposing EV batteries as energy storage devices commercially viable? In theory, it makes a lot of sense but in practice, linking together a collection of batteries that have different amounts of useful life remaining calls for some very sophisticated engineering. Tesla has already decided it is better to recycle used batteries to recapture raw materials rather than repurpose them. But Nissan and Volkswagen think there may be value to finding a second use for EV batteries that are no longer suitable for powering a vehicle.
In Hamburg, Germany, Volkswagen has packaged fifty 9.9 kWh batteries from Passat GTE automobiles inside a shipping container and installed it at a VHH bus terminal in the Bergedorf section of the city. When networked, the batteries will have a nominal capacity of 450 kWh.
VHH is the local transportation company for the area and has several electric buses manufactured by MAN Truck & Bus, a division of Volkswagen, in its fleet. The batteries are mounted on racks and then interconnected via a battery management system to form a large battery. One objective of the project is to develop a flexible battery storage concept which allows for the replacement of batteries, according to a MAN press release.
Stefan Sahlmann, the head of MAN Transport Solutions, says: “Battery second use is an extremely important topic in view of the ever-growing electrification of mobility as a whole. In the Bergedorf quarter of Hamburg, we want to investigate how used batteries behave together with our project partner – so that we are able to develop future applications based on that. The project with VHH and Volkswagen is part of our strategy to make transportation of the future sustainable.”
The Hamburg installation is very much an experimental project. Different scenarios will be tested to optimize power consumption at the VHH depot. The objective is to improve utilization of the network and cushion peak loads when the electric buses are being charged. In addition, the project hopes to learn more about how the second-use batteries age and how to develop more efficient battery management systems. Those findings could play an important role in developing future battery technologies that prolong the life of lithium ion batteries.
Alexander Adler is in charge of the second-use energy storage system. He says, “With the peak shaving method, the storage system can reduce up to 600 kW of peak load, and thereby lower the costs when using electricity.”
Nissan & American Electric Power Team Up In Ohio
Another second-life battery experiment is taking place in Ohio involving Nissan and American Electric Power, according to Bloomberg. They are using technology developed by Relectrify, a startup based in Melbourne, Australia. The company says it has come up with new inverter technology that is significantly less expensive than anything else on the market. The company says its systems can extend battery life by a third and lower energy storage costs by 50%.
“The inverter is the Achilles heel of energy storage,” says Bradley Smith, president of Beauvoir Consulting Services and previously an executive developing second-life battery products at Nissan. The Relectrify system combines an inverter with a battery management system, leading to lower system costs. American Electric Ohio is using expired Nissan LEAF car batteries in a real world test designed to verify the results obtained in laboratory testing.
Cheaper energy storage with batteries could provide an alternative to adding more capacity at electricity substations or building more transformers. It could also be harnessed to provide backup power and bolster reliability for consumers, according to Ram Sastry, American Electric’s vice president of innovation and technology. “There are many use cases that we have for batteries that are predicated on the cost,” he says. “If the battery goes lower in cost, it can compete with the wires.”
Some potential end users remain wary of reusing lithium-ion batteries. They have concerns about their longevity and the costs of repurposing cells, according to BNEF’s head of clean power Logan Goldie-Scot. “Many customers are not yet comfortable with second-life batteries even at a steep discount,” he says. The real world testing in Ohio may help allay some of those fears, leading to a greater use of repurposed EV batteries for energy storage by utility companies like American Electric Power in the future.