Every time a new battery chemistry or even pack design is implemented, development funds are spent.

Does Nissan e-NV200 Show Change of Policy on Battery Heating, Cooling?

Like humans, lithium-ion battery packs operate best in temperate climates, where it’s not too hot or too cold. Essentially, they like to be about the same temperature as us for peak energy efficiency, which is why many electric car manufacturers install liquid cooling and heating systems inside their cars’ battery packs to make it easy to heat or cool the pack as required to keep them healthy and happy.

You can see two coolant pipes coming from the front of the e-NV200, and entering its battery pack.

You can see two coolant pipes coming from the front of the e-NV200, and entering its battery pack.

From the time its all-electric LEAF hatchback launched in 2010, Japanese automaker Nissan has maintained that it hasn’t needed to use any form of active liquid thermal management system for its battery packs, opting instead for passive forced-ventilation air cooling from driving the car along in hot weather and simple battery heating pads for extreme cold.

But at yesterday’s international launch event for the Nissan e-NV200 electric van — a vehicle which shares the same 24 kilowatt-hour lithium-ion battery pack and 80 kilowatt electric motor found in the Nissan LEAF — we noticed something rather interesting which makes us think Nissan might be rethinking its policy on battery heating and cooling.

The e-NV200, unlike the Nissan LEAF, has a small air conditioner built into its battery pack.

Plumbed in

Although Nissan mentions the fact the e-NV200 has an active battery cooling and heating system in its press release accompanying the e-NV200 launch, it wasn’t until we examined the battery pack more closely in a cut-away model on display that we understood how it worked.

The cutaway showed how the e-NV200 was put together.

The cutaway showed how the e-NV200 was put together.

Despite using the same capacity battery pack and identical battery cells to the LEAF, the e-NV200’s battery pack is more tightly packed together under the floor of the e-NV200 than it is in the LEAF.

As with the LEAF, cells are stacked, one on top of another, in an under-floor, sealed battery box — but at the front of the battery compartment just ahead of the first row of cells is a small radiator and large electric fan. And entering the battery pack from the front is a coolant feed from the van’s air conditioning system.

How it works

Nissan wouldn’t go into too many details with us, but it looks as if the e-NV200 can send warm or cold coolant from the van’s main HVAC system to the small integral radiator within the battery box. Air is then drawn through the radiator fins and is then cooled or heated as needed to keep the battery pack and battery box at optimum temperature.

In this photo, you can clearly see the radiator and the fan behind it, drawing cool or warm air into the battery pack as required.

In this photo, you can clearly see the radiator and the fan behind it, drawing cool or warm air into the battery pack as required.

It’s important to note here that unlike some battery packs with liquid thermal battery management, the e-NV200 doesn’t have pipes running in between inside the battery pack. Since the battery itself is sealed in one large battery box, the radiator at the front serves a similar function to the heater matrix inside the van’s cabin: keep everything inside that closed space at a pre-determined, set temperature.

Why is it needed?

Nissan says the addition of the internal radiator is to keep the battery pack’s temperature at optimum operating conditions, since the more tightly-packed battery pack of the e-NV200 has less space for air to circulate around the cells and therefore is more prone to changes in heat than the LEAF battery pack.

There’s also some allusion from Nissan that it expects the e-NV200 to be treated far more roughly than any of its LEAFs would be. As well as the obvious misuse from the hands of delivery drivers or high-milage fleet life, Nissan engineers told us they wanted the e-NV200 to cope with frequent rapid charges in a single day without damaging battery life.

We observed no sign of thermal strain on the battery pack during our time with the vehicle

We observed no sign of thermal strain on the battery pack during our time with the vehicle

But there’s also the simple fact that with its much larger surface area, heavier weight and 770 kg cargo capabilities, the e-NV200 can’t travel as far per kilowatt-hour as the LEAF. Although NEDC range is set at 170 kilometers, our expectation is a real-world achievable range of 60-70 miles when empty and perhaps less when fully laden. In that situation, the battery packs need to be at optimum temperature to give the best possible range.

What about the LEAF?

When it came to market in late 2010, many criticised Nissan’s all-electric LEAF electric hatchback for not having any form of active battery cooling or heating system fitted as standard. Unlike cars like the contemporaneous Mini E, Tesla Roadster and Chevrolet Volt — all of which used active liquid thermal management to keep their battery packs operating at optimum temperature — the Nissan LEAF simply came with passive, forced-air ventilation.

You can see how tightly packed the e-NV200's battery pack is.

You can see how tightly packed the e-NV200’s battery pack is.

At the time and even today, Nissan maintains that the LEAF’s battery pack doesn’t need any form of active cooling or heating system to keep its battery pack healthy. To date the only concession Nissan has made to LEAF battery temperatures is to include a cold weather package with simple heating elements to keep the battery pack above -15 degrees Celsius in cold weather environments.

For LEAF owners in ultra-hot climates like Arizona however, a lack of battery cooling in the LEAF has lead to some pretty shocking premature ageing, rapidly decreasing battery pack capacity due to prolonged 50+ degree Celsius temperatures. And while all Nissan electric vehicles come with a battery warranty that covers the effects of premature battery ageing due to extreme heat, Nissan’s experiences in Arizona has led it to develop a more temperature-resistant battery chemistry, a chemistry which Nissan is readying for production later this year.

No one we spoke to at Nissan would confirm or deny the possibility that Nissan is considering active battery cooling or heating for future electric vehicles, nor could we get any indication of the feature making its way into the next generation LEAF, a car we’re expecting to debut some time in 2016/17.

A cutaway e-NV200 evalia minivan shows you where the battery pack lives.

A cutaway e-NV200 evalia minivan shows you where the battery pack lives.

But after seeing first hand how our own LEAF’s battery packs like to heat up in hot weather when rapid charging — not to mention seeing how little the e-NV200 vans appeared bothered about the hot Spanish sun yesterday — we can’t help but think Nissan is about to make a u-turn on its battery cooling policy.

We’re not engineers of course — nor can we tell for sure — but given how alike the LEAF and e-NV200 are, we think it’s highly probable.

What do you think? Leave your thoughts in the Comments below — and we’ll share with you our first impressions of the all-electric e-NV200 van in the coming days.


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  • vdiv

    So if Nissan redesigned the battery pack in the e-NV200 why didn’t they increase its capacity to accommodate for the lower efficiency/range of the van?

    • Surya

      To keep costs down of course.

    • Greener

      I agree! Nissan could have at least offered longer range battery packs as an option if cost is an issue.

    • I think they will in future models. Nissan have suggested they will offer pack size options in the LEAF in a few years. They may not have been able to get there just yet from an engineering and cost perspective.nnnAs easy as it sounds to us, I’m sure there is a lot of detailed engineering work necessary to allow for multiple pack sizes. As one example the LEAF controller and software was designed for a fixed size pack from the get go. Tesla designed multiple pack sizes from day one and built that possibility into all the vehicles physical and software systems. Nissan have to go back to the drawing board and redesign a myriad of systems to cater for multiple pack sizes. Essentially they are paying now in spades thanks to their initial myopic view.

    • ivyespalier (Randy)

      because they are the same cells. They would have to offer a 36 or 48kWh battery. Perhaps they will offer a longer range version when the Gen 2 Leaf comes out and thy offer the van for the US market.

  • The last photo is most interesting u2026 basically Nissan took a LEAF pack removed a middle stack of modules and slid the front module stacks back; adding a removed module to the top of each stack. This makes the pack more uniform in thickness from front to rear, a good thing. These changes evolve an eNV200 battery pack to be a bit similar in design to a Tesla pack; by having a more consistent layout of modules, and moving the pack management components to the front (vs. middle).nnOdd is the horizontal stack of modules at the rear of the pack given the front stacks are now as high as the rear. Two rows of horizontal module stacks would be more compact making room for a third row? Or, if the horizontal rows positioned front to back (vs. side to side) could be longer. ie: more efficient packing could add capacity without effecting height of the pack. nnA full-on horizontal module stacking would enable an option to offer an increased battery capacity by using 3p2s modules vs. 2p2s modules. (ie: 36 kWh vs. 24 kWh pack at same 360V pack voltage)nnIt is huge that a heat exchange radiator has be added inside the battery pack. Being air based it will be limited by how fast it can remove/add thermo energy compared to liquid thermo management. The horizontal stack at the rear of back will receive the least thermo management due to clear circulation path and compactness compared to the rest of the pack. A large heating/cooling pad would provide more uniform thermo management.nnOf note: the LEAF pack and eNV200 pack will not be interchangeable due to different thicknesses and location of the disconnect switch. The modules do appear to be of same design as used in the LEAF.

  • Surya

    Doesn’t Nissans sister company Renault also have a slightly more active thermal system for the ZOE?

    • Mike D

      The way the ZOE is by tripping out the entire block ;-)nnnZOE is a real shame… nice design … poor technological choices.nRenault should seriously consider firing the Camelon charger engineer.

      • Odd comment. The Chameleon charger is one of ZOE’s primary features that sets it apart from other EV’s.

        • Mike D

          The Chameleon looks good on paper… but it a nightmare in the field.nnnIn essence it was designed with the French electricity grid in mind… is not even reliable there … and causing a bigger mess in less stable grids such as Norway and their antique earthing system.nnnFrench engineering for you

          • Thanks for sharing your field experiences!! Didn’t realize it was a boat anchor.

          • Surya

            It hasn’t been for me.

  • MEroller

    All Li-based (and probably every battery technology in the world!) has a specific cell temperature range in which it works best and the longest. That Nissan opted to almost ignore this fact in their first Leaf version was maybe the biggest mistake they made for this model. n15u00b0C is by my experience about the lower sound barrier below which no real fun can be had. And above around 45u00b0C the electrolyte can begin to degrade, despite the MASSIVE fun that could be had! Best results all around should be between 25 and 35u00b0C cell temperature, so the battery pack should strive to reach that level ASAP after vehicle start, or better still BEFORE vehicle start.

  • czhp01

    If the battery box is intact for the cooling, can the Nissan Leaf be retrofit with some tubes to connect to air conditioning unit?

  • Greener

    The next generation LEAF absolutely need active thermal management for batteries. nnnThere should be no EV without active thermal management for their battery packs especially Lithium based. If future battery chemistry turn out to be very temperature tolerant such as the new Carbon batteries, then that could be an exception. Such Carbon battery packs would be perfect replacement batteries for current generation of LEAFs in fact since they don’t have active cooling or heating. nnnNissan was wrong with their passive cooling design in their first generation LEAFs but they won’t admit it.

    • ivyespalier (Randy)

      I think you are, sadly, right. Thermal management is a must. It may not be needed in Norway and other cold markets, but in the US, yes, it is needed.

  • Willie McKemie

    I claim that Nissan made a poor choice of battery chemistry rather than a poor choice of climate control on the Leaf. I bought a 1st year Leaf and drove it two years. I saw my range decline from nearly 100 miles to about 65 miles. Nissan declined to fix the battery claiming it was “fine”. Rather than waste time seeking justice from Nissan, I bought a Tesla and sold the Leaf. Before I bought the Leaf, I had a conversion with ThunderSky LiFePo cells. I operated that car in a time period that contained my Leaf ownership period and drove it twice the distance. The un-heated and un-cooled ThunderSky cells lost less than 10% of capacity. The killer for the Leaf (but not the ThunderSkys) seemed to be a summer where, here in Texas, we had about 100 days above 100 degrees.

    • I believe a combination of a better chemistry and active cooling/heating is necessary. Better chemistry may do well in the heat of the summer, but all cells under perform in frigid conditions. nnnThis winter was very cold here in Tennessee, I saw my range drop off precipitously during the weeks when temperatures plunged well below freezing. A small heater in the pack that operated after the charge completed (while still plugged in) would have been very welcome and would have preserved much of the vehicles range during the winter.nnnThanks for sharing your experiences with the LiFePo cells vs the LEAF’s. Anecdotal but illuminating nonetheless.

      • Willie McKemie

        With the Leaf, I did notice that cabin heat on shore power did a poor njob of warming the battery. Same deal on the Tesla; the battery is ngoing to be cold on a cold morning no matter how warm you get the cabin.n An exception: One frigid morning in Normal, I drove a few miles from an hotel to the SuperCharger to charge. The battery seemed to be nice andn warm on departure. The same might be achieved on the Leaf if you have nconvenient access to a chademo.

        • I wasn’t suggesting cabin heat to warm the battery, as you say it isn’t effective. I was intending that the A/C Unit INSIDE the battery pack do that using on shore power.nnnChademo charge rate drops to half when the battery is cold, so instead of 20 minutes you’re talking 40 minutes for the same charge. A full charge on the LEAF adds about 6 degrees F to the pack temperature.

      • dm33

        There is a battery pack heater in the 2013/2014 LEAF

        • Indeed there is, but it only kicks in to preserve the battery from freezing below zero. Turns on when the battery reaches -4F and then turns off when the battery reaches 14F Once the battery gets below 35F the range is already falling off a cliff. A true heater could maintain ideal temps using shore power.

        • Greener

          That heater is in my 2012 too according to it’s owner’s manual.

  • An actively air cooled/heated pack maybe a reasonable compromise versus a more expensive liquid cooled pack that other EV manufacturers use.nnnI imagine Nissan are being coy about the LEAF’s adoption of the same heating/cooling technology for a few reasons I can posit.nnn1. They will test this cooling/heating in the EV200 and see how it does in the real world over the next year or two. If it does well they will surly adopt it in the LEAF, at least as an option. If it doesn’t work very well then they can stick to their position its only needed in a vehicle that will be subject to more abuse and go back to the drawing board for the LEAF battery pack.nnn2. If they announced this technology for the 2016/7 LEAF now, sales would be impacted as buyers wait for the improved technology, especially in key markets like LA, Nashville, Dallas, Atlanta. nnnOne hopes they are building retrofit capability into the 2015 LEAF should they opt to add active heating/cooling in a future model.

    • ivyespalier (Randy)

      Since most Leafs are leased, it wouldnt impact sales

      • An analogy is cell phones. Most are ‘subsidized’ by a 2 year contract not bought outright. If a new phone is announced too early it will cause folks to wait even though they aren’t ‘purchasing’ the phone outright. Same will apply to vehicles. If there is active cooling/heating feature that will enable the same car to go further in extreme temps, folks will wait for it to come to market once an announcement is made its coming.

        • ivyespalier (Randy)

          It shouldn’t have much impact unless the person looking at the car lives in a desert.

  • dm33

    Nissan is reneging on the battery capacity warranty for early adopters. http://www.mynissanleaf.com/viewtopic.php?f=27&t=17045

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