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You may not be able to buy a Fisker Karma just yet, but thanks to MIT you may learn a little bit more about the plug-in's battery life. Back in January 2010, it was announced that the Karma would be using batteries supplied by A123 Systems, which just happens to be an MIT spinoff company. The MIT Electric Vehicle Team is using these A123 batteries to perform a variety of rapid charging tests to get an idea of pack longevity. In one test, they took an A123 cell and performed an automated 1,500 rapid charge-discharge cycles. After the torture was over, the battery had lost less than 10 percent of its original capacity. If that translates over to real-world longevity, it could be significantly better than the Nissan Leaf's expected battery life. Recall, Nissan says it expects 70 to 80 percent capacity after 10 years.
The MIT EV team has also removed the combustion engine in a Ford-donated 2010 Mercury Milan hybrid, converting it to a pure electric courtesy of 8,000 (!) A123 cells. However, to rapid-charge such a pack requires an expensive commercial-level charger, for which they are currently looking for funding.

Of course, all of this is a moot point in the U.S. until we can get some sort of standard for Level III fast-chargers here. Can't we just adopt CHAdeMO and call it a day?

[Source: TFOT | Image: Patrick Gillooly]


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    • 1 Second Ago
  • 23 Comments
      harlanx6
      • 4 Years Ago
      Wait a second here. We know EVs are coming, but there are still a lot of good reasons for people to reject them in their present form. Some people want just cheap clean transportation and don't feel compelled to make a green statement. I am all for EVs, but they still have limited use, very limited supply and almost no infrastructure. This transition is going to take patience, time, and better products.
        bajohn3
        • 4 Years Ago
        @harlanx6
        Harlan, the infrastructure is already in place as every home and business has electricity.
        • 4 Years Ago
        @harlanx6
        @harlan:
        'Even power company officials admit 50% of electrical energy is lost in transmission. '

        !! I think you mean in generation and transmission! :-)

        More generally, the emissions associated with generating electricity are on a declining path, whilst the number of charge stations, battery capacity and range will all improve.
        Of course, as a personal decision it is entirely up to you when and if you want to get on board, but it seems perfectly reasonable to be an early adopter, and if the range limits bite, then none of your strictures apply to a plug-in hybrid.
        • 4 Years Ago
        @harlanx6
        "EVs are not clean enough to gather fanatics because the power they use isn't clean. It can be, but it isn't yet."

        Burning 100% coal and using it as energy is *still* cleaner ( from the mine to the battery ) than burning gasoline.
        Additionally, electric cars have regenerative braking and don't idle. That's another advantage.

        "To be free of the government, Exxon, and PG&E is real freedom."

        Will you ever be able to fill up a gasoline/diesel car with some fuel that is not from an evil megacorp? at least with an EV, you can generate your own power 100% carbon free, 100% sustainably.

        "very limited supply and almost no infrastructure."

        Infrastructure is in your house. Many 'test market' states have chargers all over the place too.
        Limited supply should be only a problem for a few more months as production starts keeping up with demand :)
        • 4 Years Ago
        @harlanx6
        Electricity transmission is like 96% efficient. You are quite mistaken there.

        You really seem to be trying to find any excuse you can to pound on EVs. No need for that . . . just stick with cost. EVs remain very expensive. But that gap is narrowing.
        • 4 Years Ago
        @harlanx6
        If people completely reject them in their current form then it will be even longer before you get better ones.

        The current crop does the job. And if we keep the market alive, we will get better models in time. Limited use? Yeah, they can only handle 90% of driving. No infrastructure? There are far more outlets in this country than gas stations. Some people even have electricity in their own homes!

        It will take time, but it is really REALLY nice to see the transition finally start in earnest. It may be slow initially, but there is no turning back this time.
        harlanx6
        • 4 Years Ago
        @harlanx6
        John, just try to get a charge out on the hiway. You are right and you are wrong. If you stay within your EV's range you are right. Anything else and you are out of luck. EVs are not clean enough to gather fanatics because the power they use isn't clean. It can be, but it isn't yet. If you are fortunate enough to have a solar garage I don't see how EVs can be beat. Most people don't yet have that option, but it is well worth pursuing. To be free of the government, Exxon, and PG&E is real freedom.
        harlanx6
        • 4 Years Ago
        @harlanx6
        No it's not yet. Even power company officials admit 50% of electrical energy is lost in transmission. When they employ the carbon capture technologies they are developing, maybe. I stand by my statements. EVs are going to have to be better, cheaper and cleaner before I pull the trigger. Electricity pretty much still has the same problems your ICE does, but for electricity there is light at the end of the tunnel, but it's going to take some effort. I will be denegrated of course by the EV fanatics for telling the (inconvenient) truth.
        • 4 Years Ago
        @harlanx6
        "Even power company officials admit 50% of electrical energy is lost in transmission."

        Citation Needed.

        The EIA finds about 7% losses between generation and consumption nationwide:

        http://www.eia.doe.gov/aer/

        I consider them about as authoritative as it is possible to be with such a large diverse system.
      • 4 Years Ago
      This article makes vague reference to the issue of cell charge balancing. Does anyone know how level III charging systems do this? It doesn't seem any external charger can do this, the vehicle has to do it itself. So how does it happen?
        • 4 Years Ago
        What royharvie says.

        In large packs like this, the BMS does the balancing and battery monitoring. The BMS then talks to the charger to say 'gimme more' or 'stop now' or 'gimme some, but slower'.

        • 4 Years Ago
        Charge balancing is part of the car's battery management system and has nothing to do with the external power source. The car is in constant communication with the charge unit and can specify the voltage it wants. The car is also informed of the maximum amperage available and the car can control how much power it draws by specifying the voltage. For charge balancing there are circuits within the battery to bypass cells that are charged more than others so they can all be balanced.
        bajohn3
        • 4 Years Ago
        Any charge balancing can only happen near the end of charge since that's where differences will show up. Fast chargers will probably not give 100% charge as it needs to taper off to a lower current as it nears full, and that's when balancing takes place, if it's needed. Closely matched cells need little if any balancing.
      • 4 Years Ago
      Can you please tell me if your team employs any thermal management for the battery? liquid cooled or air cooled, if any?
      What is the temperature operating range for the battery? Other battery like M1 has a range from -30 C to 60C.
      Thanks in advance for your reply.
      • 4 Years Ago
      This is encouraging, at least for this chemistry. It does not necessarily convert to 10 years of real life (even ignoring aging caused over time from heat, freezing and other real life issues) unless you are using less than 50% of your battery daily and charging every second day or less. Also how rapid or complete is the rapid charging? 6 min to 90% state of charge is fantastic and almost competitive with fueling internal combustion. 1h to 70% is not.
      • 4 Years Ago
      Glad to hear it. This is an area that needs lots of research. How can we make batteries that can be fast-charged? How should fast-charging be done in a manner that maximizes speed but minimized damage to the battery? Etc.

      Very important work.
      • 4 Years Ago
      In regard to fast charging, SAE has a number of standards and committees in place to facilitate and standardize Level III Fast charging. There are a number of manufactures that currently manufacture and sell systems such as AeroVironment,. ETEC, AkerWade, Epyon and others. The key is the charge control and management system which monitors temperature, SOC along with other parameters. One issue is that the utilities are against these and "claim" a potential sag on the grid.
      • 4 Years Ago
      WAIT A MINUTE!!! If rapid charging doesn't totally destroy batteries, what will all the nay-sayers have to bitch about? Don't ruin their fun LOL
        • 4 Years Ago
        Yeah, I know.

        The A123 batteries can go as high as 30C on discharge and other chemistries will start falling apart at 3C. So they are all very different and you would have to see this type of testing on a variety of battery chemistries to really get good data. But the A123 batteries are not particularly cheap and their energy density is not that great either. It's all about tradeoffs. But it is nice to know there is some hope for a car with a 100-150 mile range if it really has to occasionally rapid charge.

        But mostly, I am just having fun with folks who like to always be negative about anything to do with EVs. :-)
        • 4 Years Ago
        It doesn't ruin A123 batteries. Those are fancy expensive batteries. Other batteries often don't fare as well.
      • 4 Years Ago
      Remember that A123 cells are different than other cells in this regard. They have many multiples of the C rating for charging that most battery chemistries have.

      Most batteries like to be charged at 1C-2C, but i have heard of people charging A123 cells at 4C+ without ill effect on the batteries lifespan.
      • 4 Years Ago
      I don't think I need fast charging. I think I'll have a different car for long trips, or rent something. Someone else pointed out too that A123's battery can take the fast charging but other higher energy chemistries can't. So, maybe what is needed is a hybrid battery that would allow you to use the high current capabilities of the A123 battery for large accelerations ( and for accepting the high current of braking recovery) and an energy battery that would supply the based load requirements. This would give you better range than the A123 battery and a partial fast charge, say maybe 80% of the high current battery in 5 minutes. This might only give you an addition 30-50 miles range, but if charging stations were plentiful enough you would never be stranded.
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