Why Alstom is helping teach old EV batteries new tricks

Wed, 2014-09-24 06:00 -- Doug Cooley

Do the lights in your office flicker when the electric car drivers start arriving for work?

That could be the case as more and more electric vehicles (EVs) show up in company parking garages and plug their vehicles into charging stations. Dozens of simultaneously charging EVs can add up to a huge hit on a building’s power network.

The Eco2charge project, sponsored by a French consortium that includes Council Lead Partner Alstom Grid, is addressing this predicted problem. It’s now testing a charging solution that takes old batteries which once served to power EVs and re-uses them to charge batteries currently installed in the cars.

The key idea is that the charging station built out of old batteries can draw and store electricity at night when the demand on building power is low and discharge it to cars during the day when demand for building power is higher. The project sponsors believe the scheme will help building owners avoid having to upgrade their power networks to accommodate the growing EV market and its charging station requirements.

The $16.8 million initiative is expected to make its way to office buildings, parking lots, campuses and other sites where fleets of electric cars park. "In about a year we will have a commercial offer," Servan Lacire, Bouygues Energies & Services director, said in a Reuters' article. The company is the lead construction firm on the project.  

Putting 47,000 batteries back to work

The Eco2charge system relies on lithium-ion batteries from carmaker Renault, which sells several electric car models and is also a project partner.

With Renault’s electric cars, the batteries are rented by car owners, and replaced when they dip to 20 to 25 percent of their charging capacity. This means Renault is left with a lot of retired batteries lying around -- about 47,000 batteries at last count --that still have a fair amount of capacity. These salvaged batteries are assembled together and charged up to create stationary power storage. "It is a very cheap form of storage, as the cost of the batteries has already been written off for use in the vehicle," said Renault’s Thomas Orsini.

The charging system will work for all brands of vehicles, not just Renault, adds Orsini.

Lego blocks storage system

The Reuters article points to several other ideas swirling around the battery-based power storage system.

  • Power system managers could connect salvaged batteries into modules "like Lego blocks" for use with solar power stations and wind parks.
  • The storage system could be incorporated into a grid-wide demand-response system. Energy managers could easily take the storage system off the grid to reduce demand, and feed power back into the grid at times of peak demand.

Reuters notes that European utilities are rallying behind electric cars usage as a way to increase power demand, which has stagnated because of struggling economies and increased energy efficiency.