Leaf to get 186 miles of range

Not necessarily. More battery banks within the pack could allow for greater cooling flexibility. Shifting demand to a cooler section is not a new air-cool strategy. Intel adopted that approach for their processors and it has proven very effective. Liquid cooling has not been necessary.

It's a matter of well thought out gauges and software control.

After all, introducing a liquid-cool system is in the wrong direction for cost-reduction... which is very important with the expiration of the tax-credit rapidly approaching.

 

IIRC the subsidy winds down the same way the Prius subsidy worked:
Full subsidy the quarter that the total sales are reached
50% subsidy for the next quarter
25% the last quarter

 

It's a phase-out, supposedly at the same rate as in the past... to 50% for 2 quarters, to 25% for the next 2 quarters, then 0%.

 

OK so Leaf hit 50,000 US units by June 1 lets say selling 3000/month.
Estimated say 75k by end of year and maybe 140k Leafs sold by end-2016, so could be some room left.

 

It seems like there's always a great headline here then when you read it, it is just hype.

 

Wouldn't it be fair to expect the "real world EV mileage" to be lower?

 

Federal subsidies run out at 200,000 units. They will likely go down in value quickly for other manufacturers once the first one makes it.
In the US plug-in market
Nissan has sold 57,858
Chevrolet 66,164

My guess is GM or Tesla will be the first to 200,000. Nissan should be close enough to claim all 200,000 credits. That leaves 400,000 for toyota, ford, bmw, hydunda, mercedes, etc, and some of these might only pay 50%.

 

i would hope the next gen has more efficient batteries, i.e. smaller, denser. plus a new design to hide them better.

 

Comparing a PC to Leaf's traction pack:

PC interior has LOTS of room for air movement, with big fans & heat sinks (compared to the size of the CPU's). PC is typically in a room that's comfortable enough to workers ... and with banks of CPU's they're often cooled to keep the PC's their self cool.

Traction pack has LITTLE space, often competing with cargo or interior room. Leaf modules are VERY close together, providing the least amount of space that can be donated to cooling. Heat is not only generated by use (discharge) it's generated n the flip side, charging. Traction pack is must survive out in the 90° - 110° or higher heat. Now you have a device that's heating itself, AND out in the heat ... AND tightly packed, making it difficult to circulate the hot temps around it.

Not a pretty design. When owners confronted the Nissan spin folks, they told the audience that there's nothing wrong with air cooling ... why? .... they said because it works fine for people. Really? Last time I checked, when people are roasting, they start sweating ... and it's through the body's water/evaporation that we cool. They need to re-think that snappy come back. With liquid cooling, the car can use it's heat pump to generate chilled temps, that transfer that quality to coolant, that can pass over modules so that they can go below outdoors's ambient temperatures. In reverse, on frigid days, the system works to warm the cool packs to a temperature that makes them more efficient. Heat pumps using liquid coolant give the best of both worlds.

Active liquid cooling - they're more expensive, but as I mentioned in the earlier post ... you pay for better cooling - or pay for premature module death.
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I should say "Prius Driver" world. Real world yes would be lower. Real World Prius Drivers would be higher because they are hypermiling, driving carefully, efficiently etc... I constantly get above 50 mpg in my Prius. And plugin owners get above 11 miles EV

 

This is not a new issue, but an ancient issue. The old VW bug engine had the great advantage/disadvantage of being air cooled. I'll leave it to the readers to decide if it was a step in the right or wrong direction.

 

This is a different issue. The old vw ice was relaible, but liquid cooling reduced NOx and increased efficiency, while adding cost and weight. How much cost? Well cost really was small compared to the hp gain you can get from liquid cooling. The hp gains easily outtweigh the gained weight.

On the leaf, before it was produced tesla warned that the pack would have worse aging characteristics. Real world results show this greater aging than the tesla and chevy liquid cooled packs. Nissan thinks a chemistry change will work. I say we will know in 2 years. I wouldn't touch it in a hot climate until it is proven.

 

It certainly is a different issue in detail, but not in overall physics. There is no right or wrong answer here, other than if the correct priorities were thought of when picking a particular approach. The issue about the Leaf would be answered if we had a time machine and could see what initial decision(s) Nissan would have made with the knowledge that some really hot locations in the USA really do overstress the Leaf battery. It is the kind of decision that Nissan cannot be seen second guessing in public. The Leaf is their flagship. But there are definitely intense discussions in the backrooms of Nissan engineering/senior management about what should have been done to prevent this situation to begin with. A mistake was made somewhere. Toyota certainly was successful in their decisions about Prius battery air cooling, so it is not a right vs. wrong, but much more a battle of correctly engineering the technologies of the time.

(PS Even nuclear reactors have engineering battles between gas and liquid cooling...past and present.)

 

Nissan engineers claim they knew the batteries would lose 30% of their capacity during the first few years (and then stabilize with no further loss). So it wasn't really unexpected. It was part of the plan.

If EV credits are phasing out, then it sounds like we should buy our EVs now before the free cash disappears.

 

Take a look at the new i7 machines. They have very little room inside, yet deliver an impressive amount of portable power.

 

No automobile company lets any engineer speak about real issues except what has been scripted by the PR office.

 

Let me fix that for you:
No company lets any engineer speak about real issues except what has been scripted by the PR office.


iPad ? HD

 

Its much easier to get info from engineers at conferences and symposiums. But then again you are dealing with engineering supervisors or really new, raw engineers working on just a focussed part and have no real knowledge of the overall general design but are there to back up the supervisor in case a really tough question comes out of nowhere.

Nothing is scripted there but tightly controlled. No press unless they are escorted. Nobody talks shop during the many "socials" but that is where the networking happens, both socially and professionally, depending on how much alcohol is involved.


iPad ? HD

 

I have recently completed builds on a couple i7 PC's and it's quite roomy (turns on the size of the case you use). But for grins, let's just say it's not roomy, but cramped and only the heat sink is available for cooling. Let's pretend the little small footprint of the i7 processor, under that big fan AND big heat sink represent the ratio between them & the Leaf traction pack:




The Leaf battery would need a fan & heat sink that would literally have to be almost half the size of the Leaf it self. But again, it'd still be blowing hot southwestern US summer temps into & around the pack. And what happens to many Lithium chemistries when subjected to temps in the 120° + range (yes, the packs get even hotter while charging) ? .... it kills their capacity. There's just no way to paint that as a pretty picture.
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The i7 being used to type this reply is only 5mm tall. It most definitely is not roomy. In fact, I'm rather amazed how it can be so thin, yet deliver so much power.

Anywho, the point is draw & recharge won't be allowed using hot air. The requirement of cooled-air intake is quite necessary. That's not rocket science though, it's just running A/C during those times. We could even imagine the battery-pack taking precedence in some situations too, having a direct feed of that cold air in times of need.