Nissan Discusses Method For Topping Off LEAF Battery

1 year ago by Eric Loveday 39

24 kWh Lithium Battery Found Inside The 2013-2014 Nissan LEAF

24 kWh Lithium Battery Found Inside The 2013-2014 Nissan LEAF

2016 Nissan LEAF Getting A 6.6 kW, "Level 2" Charge

2016 Nissan LEAF Getting A 6.6 kW, “Level 2” Charge

It turns out there’s a way to stuff an extra 0.7 percent of energy into a Nissan LEAF battery pack and it’s easier than you might expect.

According to Automotive News:

“To cram more charge into the lithium ion battery of the Nissan Leaf electric car, Nissan Motor Co.’s battery engineers turned to the tap for inspiration.”

“Their breakthrough: Top off the battery with three extra minicharges at five-minute intervals at the very end of charging. It is similar to an expert bartender waiting for the foam to die down before topping off a beer with a couple of tap blasts.”

News of this topping off method comes from Taiichi Onoyama, leader at Nissan’s electric and hybrid system engineering department, who stated:

“In our company, we talk about additional charging using this example of how to pour beer.”

0.7 percent isn’t much, but it could be the different between arriving at your destination and getting stranded with no charge on the side of the road.

As Automotive News explains (via slides shown at a conference in Tokyo):

“The secret lies in allowing the cell voltage to dip a bit between charges, just like the foam on a beer. The lower voltage allows the battery to accept more charge.”

Of course, it does take a bit longer to get the extra charge into the LEAF, but it may be worth the wait in some situations.

Source: Automotive News

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39 responses to "Nissan Discusses Method For Topping Off LEAF Battery"

  1. David Murray says:

    So that gets you about half a mile on the regular Leaf and about 3/4 of a mile on the new larger battery?

    1. evcarnut says:

      Yea! So there is a way to stuff Batteries in a Leak Gas Tank!….. l o l

    2. jerryd says:

      Far worse especially if the batteries are hot doing this cuts battery life.
      One should never fully charge or discharge if you want the longest life.
      98% charged and 95% discharge is quite enough.

  2. AlanSqB says:

    Sounds like an excuse for engineers to talk about beer. 0.7% isn’t going to get me up the parking ramp at work.

    1. R.S. says:

      They probably also did the field testing with beer.
      Another great solution, if you drink enough beer, you have to call a taxi, so your Leaf stays full a lot longer.

      1. AlanSqB says:

        I think that counts as “fluid dynamics.”

    2. Djoni says:

      Well beer is a social lubricant if use mildly, so this kind of charging method is very useful to use while sipping a nice one!

      1. evcarnut says:

        Beer a Social Lubricant ? That is too funny…I wish I had known that sooner, when I was taking my MB to the dealer for service., , I unknowingly kept on bringing the vasoline with me…,

  3. goaterguy says:

    Volt owners have used that trick for a while. In the morning, with a fully charged battery you remotely precondition the cabin’s preferred temperature then let it sit until it tops off again.

    1. mega says:

      The opposite seems to happen with the LEAF (at least mine).

      I’ll hit 100%, but once I have it precondition the cabin, SoC drops to around 98-99%. Never considered it a major issue (maybe balancing related), but I always wondered what the deal was.

      I always thought it tries to balance the cells @ 100%, so I’m surprised this ‘trick’ works.], unless it’s this balancing activity which allows this to happen (not an EE).

  4. Alan says:

    I have a better idea,

    How about topping off that 24kWh battery with an additional 76kWh of battery cells !

    1. Just can’t stand not having a P100D?
      Remember…this is a LEAF, not a whole Oak Tree! And Nissan said they have no intention of making a competitor to the Model S!

    2. BraveLilToaster says:

      Sure, we’ll just a magic them in there at no extra cost because it’s what you want!

  5. R.S. says:

    15 minutes for a half mile, you could also stop a half mile before your destination and walk the rest, it might be a bit more time efficient.

    1. mr. M says:

      Jup, 15 minutes of walk give you a 0.78 mile. That is way more. Since you will walk the half mile in around 10 minutes 😉

    2. BraveLilToaster says:

      Or, just as importantly, there’s enough chargers on the ground today that you can stop somewhere on the way for less than 5 minutes to get another mile into your battery.

  6. AlanSqB says:

    I thought about this more on the way to work and I think the engineers must be using a car/pack that has been modified to allow for full charging. The production LEAF is set up with a certain amount of “head space” so that the battery is never fully charged to 100% which would also leave room for the “bubbles”. Therefore, this method would probably be completely useless for a production vehicle.

    1. Dave R says:

      Cell voltage will typically settle a bit even after charging at well under 100%.

  7. SparkEV says:

    As an engineering exercise to see how much you can stuff in the battery, it’s fine. I applaud Nissan for finding out. Engineers should push the limits.

    But if you depend on that extra 0.7% to get to your destination, you will be stranded. Since Li batteries don’t do well at “full charge”, doing this will probably shorten its life (by 0.7%?). More money to Nissan if people actually do this.

    1. Dave R says:

      Yep, since resting voltage of the cells affects rate of capacity loss, they are effectively exchanging a short term capacity for long term capacity.

      The only time this might be worth is is if you plan on using that extra capacity immediately and don’t plan on getting the car sit for any significant period of time.

    2. evcarnut says:

      I hear that a free cell phone will be included with all purchases so you can call for a Taxi or a tow truck when you get stranded..

      1. SparkEV says:

        Doesn’t Nissan offer something like OnStar? SparkEV comes with free for 3 years.

        1. mike w says:

          They have a 1-800 number you call and they will tow you for free if your battery goes bad. At least that’s what they had for my 2011 Leaf.

  8. Edward Arthur says:

    I hope they name the three 5-minute charges “Ludicrous Mode” because the name would be fitting.

    1. Alan says:

      The “Pizza mode”

      Three additional toppings should just about get the job done !

  9. Bone says:

    If this was new discovery for Nissan battery engineers, I wonder what else they don’t know about battery basics.

    1. mike w says:

      Being the former owner of a 2011 Leaf I would say they knew almost nothing about batteries.

      1. Pushmi-Pullyu says:

        Ouch! 😀

        Dude, you just won the Internet.

      2. SparkEV says:

        Wow. Harsh, but true. Even Tesla roadster had actively cooled batteries, and they didn’t have DCFC. Another potential clueless might be VW; their batteries aren’t cooled, either.

  10. Anon says:

    If you don’t have a large battery to brag about, you talk about the minutia…

  11. Thanh Lim says:

    Bigger, more energy dense batteries please.

    Lots of fun and games but we all know the name of the game is the battery. I’d personally want to have a reliable car for the masses that can go 400 miles. 200 is great, but 400, there really is absolutely no excuse to cry about range anxiety.

    1. SparkEV says:

      Then the masses will be paying for / carrying around all that weight and waste energy all the time that they will rarely, if ever, actually use. 400 miles is born out of gas car model where you must drive to filling station once a week.

      I suspect “masses” will be pretty happy with 2 hours of freeway driving with AC/heat (about 150 to 200 miles)

  12. Mister G says:

    You can get more range by driving in ECO with climate control off and driving 10 mph below the posted speed limit.

  13. sault says:

    0.7% of a 30kWh battery is 210 Whr. You could “add” this much energy to your battery by getting just slightly better at hypermileing or just turn off the radio / other accessories.

  14. Ian says:

    I’d love to see myth busters take a leaf battery and see how much charge can fill it until it catches on fire or dies.

  15. Djoni says:

    It would be much more useful to program a function that allow you to pre heat the battery at its top efficiency.
    The difference between the coldest temperature the optimal one could be as much as 2-3 kWh of energy.
    Another useful thing they could do is to add the option of pre heat the cabin without draining the battery when plug in.
    All that OTA would be nice too.
    I know it wont always be cozy and summer hot, but I prefer much more to get in my car with some pre heat and a full battery charge than in a hotter cabin with a somewhat depleted battery.

  16. ModernMarvelFan says:

    “0.7 percent isn’t much, but it could be the different between arriving at your destination and getting stranded with no charge on the side of the road.”

    This is why limited range BEVs aren’t taking off in sales…

    Seriously, you are better off drafting behind a larger vehicle and you will gain far more range than this.

    *sigh*, we need 60kWh+ battery.

    1. SparkEV says:

      We don’t need 60+kWh battery. We need more range, and that could be done with smaller battery. What we need is smallest battery with longest range, and that could be done with more efficient aerodynamics. As you know, EV range is primarily due to highway.

  17. abasile says:

    I’ve occasionally used a technique like this when I need to maximize charge and simultaneously warm up a cold battery. Yes, a larger battery would be nice, but our 2011 LEAF is what we are using for now.