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Published on February 5th, 2013 | by Silvio Marcacci


Toyota Recycles Hybrid Batteries Into Energy Management Systems

February 5th, 2013 by  

A shift in Toyota’s research and development strategy could put a charge into the nascent technological application of recycling hybrid vehicle batteries into energy storage systems. 

This concept isn’t new, but Toyota’s announcement that it will sell electricity management systems comprised of recycled hybrid batteries to its vehicle dealers in Japan is fresh thinking – to my knowledge the first time an automaker has dedicated a business unit toward integrated battery microgrid systems. 

More Capacity, More Applications

Toyota’s battery systems will use nickel-metal hydride (NiMH) batteries to store up to 10-kilowatt hours (kWh) of electricity, double the capacity of another recent recycled EV battery to energy storage project. Once online, the systems are expected to help dealerships save money, integrate renewables, and provide emergency power. 

The first systems will go on sale this April and will tip the scales at 2,160 pounds – almost as much as a 2012 Prius. However, the systems will be much smaller in size (about six feet tall, four feet wide, and four feet long), meaning up to six can fit into a typical parking space.    

While the systems won’t be mobile, they’ll certainly be versatile. Toyota will bundle them in conjunction with building energy management systems, solar panel systems, and solar-powered carports.  

This ability to store electricity can help the dealerships reduce energy use during peak demand, and may prove a moneymaker by selling excess power back to the grid. In fact, after a year of testing, Toyota estimates the system’s combination of demand response and increased electrical efficiency will cut the cost of electricity and gas used for power by dealerships in half.

–>Also recommended for you: Advanced Batteries Market to 2020 — Demand for Electric Vehicles to Drive Growth, Asia Pacific to Remain the Major Producer

The Future of Emergency Generators?

Saving money is great, but providing emergency backup may be the system’s biggest asset – especially in Japan. Already wary of power outages from earthquakes or natural disasters, the country has faced severe power constraints as it has attempted a post-Fukushima transition away from nuclear power. 

Serving as emergency generation after disasters is becoming routine for Toyota, with online instructions to use a Prius for backup power, but the new systems expand the types of batteries serving as backup. Toyota also envisions the system can be used to power emergency response centers and evacuation shelters. 

Innovation Meets Opportunity

Toyota has certainly been at the vanguard of hybrid and EV development, filing the most US green tech patents in 2012, but this new announcement could simultaneously improve the economics of the battery and EV industries. 

And Toyota’s efforts are well timed, too. An estimated 2 million hybrid cars currently run on NiMH batteries, and as EV and hybrid sales grow, automakers may soon find themselves with a surplus of batteries – and plenty of energy management systems in dealerships.

Check out our new 93-page EV report, based on over 2,000 surveys collected from EV drivers in 49 of 50 US states, 26 European countries, and 9 Canadian provinces.

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About the Author

Silvio is Principal at Marcacci Communications, a full-service clean energy and climate policy public relations company based in Oakland, CA.

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  • Otis11

    How many KWh of battery are needed for a (mostly) independent home with solar pannels powering it? Say, charge with solar all day to be used in the evening and then charge from the grid to be used for the next morning.

    And how many KWh of battery are in the average hybrid? I can look this up tomorrow, but it might make a nice pairing to take them all out and use them as home storage for a decade or two after their life in a car – help make the grid more flexible.

    • Bob_Wallace

      It’s going to vary depending on the amount of electricity each house uses and how many days worth of electricity one wants to store.

      The rule of thumb for off the grid is about three days reserve. So take your average daily use and multiply by three.

      I’m off the grid and have pared my usage down more than most. Plus I live where AC is not needed. (I use a fan a half dozen days a year.)

      I sized my system to give me 1.2 kWh per day or 3.6 kWh total. Our cloudy days are almost all in the winter and when it’s cool my refer pulls well under 1 kWh per day.

      The Prius PHEV has a 4.4 kWh battery. Changed out when it drops to 80% capacity one would be pretty much what I need. But it might only be about one day storage for a more typical house.

      Now if I could get an 80% LEAF 24 kWh pack – I’d be good for over two weeks.

      • Otis11

        See, if the Prius PHEV’s pack is enough for one day on a typical house, that would be a perfect buffer system. We don’t need to remove everyone from the grid, but if a significant portion of houses had enough storage that they could remove themselves from the grid for peak demand periods (currently noon +/- 4 hours or so, but with solar with be morning peak and afternoon peak) and charge during low power times that would be perfect!

        BTW – how much would one of those systems go for? Because here in Texas we have a lot of companies offering “free nights” where the cost of electricity actually drops below 1c/kwh… Could have a very fast payback to store all day’s power…

        • Bob_Wallace

          I’m not sure that batteries and inverter would ever pay for themselves. You might be able to put a system together for $3k but it could be as high as $4k.

          Best idea, I suspect, is to install solar panels and provide your own peak power then buy cheap off-peak from the grid.

          Apparently inverter prices are going to fall in the future as rumors are floating that bunch of Chinese companies are going to get into the business. That will turn them into commodities and make them a lot cheaper.

          • Otis11

            Whoa now – if you can by the system for $4k that will pay back fast! Look at this: Average power bill during Texas Summer is $162 per month. At 12c/KWh that’s 1350 KWhs of power reduced to 1c night time rates or $13.50 for a savings of $148.50. ROI in 27 months.

            Granted that’s assuming that the $4K pack can last from 4AM until 10PM even during the summer, and charge completely in that 6 hour window, but if that’s anywhere near true the ROI on that is incredible!

          • Bob_Wallace

            Well, we can price this out using lead-acid batteries. Those are easy prices to get. Give me the power (kWh) needed to carry this hypothetical house from 4AM to 10PM.

            And we’d probably want to know the maximum draw (ACs can suck a lot).

          • Otis11

            Well going off the calculation before we would need 45 KWhs of power per day. So if we did 3 leaf packs at 80% capacity left that gives us 57.6 KWhs of power a day (for summer buffer). That should be adequate for all but the hottest summer days.

            That actually seems very high to me, but that what the numbers say – for a $200 bill per month you’re using 57 KWhs per day!

            And as far as maximum current draw – an AC unit takes 1KWh/Rated Ton. Average house has either 1 or 2 – 2 ton units, so maximum draw of 4 KW plus some change, so figure 5KW for a safe margin? Just to discharge the whole pack we would have to draw 60/20 = 3KW average load. To charge we would need the ability to push in 60/6 = 10KW average charge load.

            I believe that’s all the necessary numbers – but idk that using the price of new batteries will necessarily work, hence the use of old, “worn out” ones that should be substantially cheaper, but we can still run the numbers and find out.

          • Bob_Wallace

            My brain is kind of frazzled – time for bed. I’ll mark this one for tomorrow.

            One thing. 5kW for the AC plus whatever might happen to be running at the same time. Dishwasher + washer + electric dryer + ???. Got to size the inverter for worst case, including the surge that large motors can pull in the first seconds when they start.

            My inverter is 4 kW continuous with a 8 kW for 10 seconds rating. I’ve got a Trace 4024.

            The Xantrex 6048 will give you 6 kW continuous and tolerate a 12 kW surge. Looks to be about $3,500.

            (Trace changed its name to Xantrex)


            (I don’t know this company – altestore.)

            “To charge we would need the ability to push in 60/6 = 10KW average charge load.”

            My experience is in the < 1 kW charger range. I use a IOTA like those on this page.


          • Otis11

            BTW – in your experience, how long to these batteries last if they’re cycled daily?

          • Ronald Brakels

            Actually, for people in the Australian State of Victoria it might actually pay for itself as they have not so smart meters that can result in large differences between peak and off peak prices. But as you say, it would of course be much better to combine it with rooftop solar.

          • Bob_Wallace

            I see on one site a statement that A people use, on average, 6,570 per year per household. 18 kWh per day.

            OK, let’s try this with lead-acid batteries. Trojan has a new lead-acid designed for off-grid use. Golf cart size but thicker plates.

            T-105 RE. 6 volts. 225 amp hours. 1,350 watt hours. 1.35 kWh.

            Don’t cycle them more than 20% and they should last 4,000 cycles. 10.9 years. (4,000 is Trojan’s number, so I would expect more than 4k.)

            If you cycle only 20% then you’d get only 0.27 kWh per battery. You’d need 67 to store 18 kWh. At $150/battery that would be a bit over $10k. Just for batteries.

            I’m not sure how to price out inverters for AU. What we have here are ones with 120 vac output. Some can be stacked to give 240 volts but that doubles the price. And we don’t know the maximum load that would need to be serviced. Let me just guess $3k.

            And another $1k (?) for battery chargers. I’m not sure what the best way to charge that many batteries might be.

            When I said $4k above I was thinking a very efficient house. Something that uses about 2x as much as I do. 18 kWh is a honking lot.

            And then Otis seems to be saying that Texans use 44 kWh per day?

            Or am I too tired to be attempted this right now?

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