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garygid

garygid

Well-known member
Joined
Apr 21, 2010
Messages
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Location
Laguna Hills, Orange Co, CA
I see the LEAF's electric motor described in different places as 80 kW and 90 kW (and the battery as "90 kW").

Either way, is this the motor's "continuous use" rating (going fast up a long, steep grade type use), or "peak" rating ("floored" acceleration passing type use)?

Anybody with more (or better) e-motor performance details on the motor and inverter (the drive-system) and its cooling?

How about the Battery Pack current and temperature limits that will affect performance?

If the battery pack is really "sealed", might it suffer from flexing due to air pressure cycling?

Or, does it actually have a pressure relief valve?
 
Yes, 90kW is the peak power the battery can deliver and 80kW is the max power the engine can transform. Ideally these 2 numbers should be very close. There is no point in having a super powerful battery and a weak engine and vice versa. However that peak power should be high enough to make sure the components are not used to their maximum capacity most of the time. i.e. the power used for cruising should be much lower than 80kW.

A while ago I did some experiment with my current car (VW Golf) to estimate how much power it takes to drive at around 65MPH constant speed on a flat freeway. I don't remember the formula (using the time it take for the speed to drop from 70 to 60) but the estimated result it gave me was around 13kW. It may seem low compared to the 90kW but keep in mind that 13kW is only to fight the drag (air resistance, tires, etc...). When you accelerate is when the power peaks.

For cooling the motor and inverter I don't know what Nissan has planned but I am not too worried: A gas powered car wastes 70% of the energy is consumes into heat. Dissipating this heat is what car manufacturers have learned how to do for years. Electric and electronic systems have typical efficiencies of 90% or higher which means that only 10% or less is wasted in heat. Finding a way to dissipate 7 times less heat than a regular car was probably a walk in the park for Nissan engineers.

Temperature... yes. All batteries are based on chemical reactions which depend on temperature. Extreme cold and heat will affect the LEAF's performance and range. I guess we'll find out by how much once we get to drive them around. I am sure Nissan has used the years of tesing to make sure temperature will not be a problem.

As for your question about the "sealed" battery i am not sure what your concern is. Each individual battery is probably sealed to make sure chemicals inside stay inside. These probably do not contain much air (or none) which would expand when outside pressure changes. So pressure on the enclosure of these batteries is probably not a problem.
Now if you are talking about the larger enclosure then I don't think it's sealed. It's probably water resistant because it's exposed to the water on the road under the car but I can't think of a reason why you'd have to make this enclosure perfectly airtight. It has many connectors and accesses that would make this difficult (costly) to achieve.
 
ericsf said:
Yes, 90kW is the peak power the battery can deliver and 80kW is the max power the engine can transform. Ideally these 2 numbers should be very close. There is no point in having a super powerful battery and a weak engine and vice versa. However that peak power should be high enough to make sure the components are not used to their maximum capacity most of the time. i.e. the power used for cruising should be much lower than 80kW.

A while ago I did some experiment with my current car (VW Golf) to estimate how much power it takes to drive at around 65MPH constant speed on a flat freeway. I don't remember the formula (using the time it take for the speed to drop from 70 to 60) but the estimated result it gave me was around 13kW. It may seem low compared to the 90kW but keep in mind that 13kW is only to fight the drag (air resistance, tires, etc...). When you accelerate is when the power peaks.

For cooling the motor and inverter I don't know what Nissan has planned but I am not too worried: A gas powered car wastes 70% of the energy is consumes into heat. Dissipating this heat is what car manufacturers have learned how to do for years. Electric and electronic systems have typical efficiencies of 90% or higher which means that only 10% or less is wasted in heat. Finding a way to dissipate 7 times less heat than a regular car was probably a walk in the park for Nissan engineers.

Temperature... yes. All batteries are based on chemical reactions which depend on temperature. Extreme cold and heat will affect the LEAF's performance and range. I guess we'll find out by how much once we get to drive them around. I am sure Nissan has used the years of tesing to make sure temperature will not be a problem.

As for your question about the "sealed" battery i am not sure what your concern is. Each individual battery is probably sealed to make sure chemicals inside stay inside. These probably do not contain much air (or none) which would expand when outside pressure changes. So pressure on the enclosure of these batteries is probably not a problem.
Now if you are talking about the larger enclosure then I don't think it's sealed. It's probably water resistant because it's exposed to the water on the road under the car but I can't think of a reason why you'd have to make this enclosure perfectly airtight. It has many connectors and accesses that would make this difficult (costly) to achieve.
Click to expand...


What is the point is worrying about the pack if the warranty terms are goo. As stated over and over and like almost all advanced AC drives, the Leaf will likely be water cooled, it does not take much to do this as the heat is nominal in most cases. 80kw peak motor is a bit small for a vehicle of this WEIGHT, hence the slow 0-60 for an (EV).
 
We've seen pictures from Nissan that show the liquid cooling passages in the traction motor. We've seen pictures of the smooth inverter case with no air cooling fins. We've seen underhood pictures with a 'radiator' pressure capped bottle connected to hoses from the inverter. In these same pictures we've seen a second pressure cap and bottle that could be for the motor (but we haven't seen connecting hoses so can't confirm its function).

I think we can pretty much - greater than 80% - say that the motor and controller are liquid cooled. ;)

On the battery - we have pictures in the Nissan PowerPoint briefings that show not only spray washing and still-water dunking of the battery box, but an actual immersion in an ice bath - which creates a low pressure inside the battery box. They report that the box is completely sealed and is 100% water tight.

The pouch type cell used in the battery is a series of stacked aluminum and copper foil 'plates' that are smeared with 'magic sauce', stacked, sprinkled with the thickened electrolyte, then sealed inside 'foil pouches' completely airtight. Experiments show that some cell compression - which pushes the plates closer together - lowers the cell's internal resistance and improves cell efficiency. A slight overpressure in the battery box (but external to the cells) will actually make the battery work better.

Unless designed for flight above 11,000 feet ;) , I don't see a need for any vents in the battery box.
 
I would be interested in the expected life performance of the motor and inverter.
Will these components really go 20 years and 300,000 miles similar to an ICE?
 
There are Solectria Force, Ford Ranger, GM and Solectria S10, and others from the late 1990s that are still on the road and running strong - and those were first generation control electronics.

Stay away from nuclear blasts and their electromagnetic pulses and we should be in fine shape for many years. :lol:
 
AndyH said:
There are Solectria Force, Ford Ranger, GM and Solectria S10, and others from the late 1990s that are still on the road and running strong - and those were first generation control electronics.

Stay away from nuclear blasts and their electromagnetic pulses and we should be in fine shape for many years. :lol:
Click to expand...

We won't be able to do that in 2012 when the sun's strongest solar flares/electromagnetic pulses in over 100 years hit Earth. I know that's a couple years away, but what's the best thing to do to shield the electronics from electromagnetic pulses?
 
smkettner said:
I would be interested in the expected life performance of the motor and inverter.
Will these components really go 20 years and 300,000 miles similar to an ICE?
Click to expand...


Good luck on a modern ICE going 300K miles without much service and replacement parts. With properly lubricated bearings, an AC motor can run 100 years 24/7 with no service, this is proven today in factories. There are no brushes and there is one moving part, the motor shaft. Likely the inverter, cooling pump or other device would fail but a well built inverter should last a long time and they are easy to repair.
 
smkettner said:
I would be interested in the expected life performance of the motor and inverter.
Will these components really go 20 years and 300,000 miles similar to an ICE?
Click to expand...

I'm driving a VW Golf CityStromer (100% electric) from 1995. It has a 22 kW AC motor (so about a quarter of a Leaf), and weights over a ton and a half. It follows the normal traffic with no problems, except in hills (due to the weight of half a ton of batteries!).

In fact, the designer of the inverter (in Germany) has changed the inverter (but kept the 22 kW engine) and now cruises up and down the Autobahn at 85 mph!

So 80 kW is plenty.

Also, he has still never seen a bust electric engine, in spite of the fact that most of these CityStromers are now about 15 years old. I even have a friend with the original lead-acid batteries from 1995, which still does about 30 miles to a charge!
 
EVDRIVER said:
smkettner said:
I would be interested in the expected life performance of the motor and inverter.
Will these components really go 20 years and 300,000 miles similar to an ICE?
Click to expand...


Good luck on a modern ICE going 300K miles without much service and replacement parts. With properly lubricated bearings, an AC motor can run 100 years 24/7 with no service, this is proven today in factories. There are no brushes and there is one moving part, the motor shaft. Likely the inverter, cooling pump or other device would fail but a well built inverter should last a long time and they are easy to repair.
Click to expand...

Honda has said that the GX ICE was built to go 1 million miles. :) If you look at my oil after about 10K (recommended oil change), it looks just like new. I've seen oil (never changed) after 180,000 miles in a 100% H2 ICE pickup, and it looks just as clean as when it went in.
 
leaffan said:
EVDRIVER said:
smkettner said:
I would be interested in the expected life performance of the motor and inverter.
Will these components really go 20 years and 300,000 miles similar to an ICE?
Click to expand...


Good luck on a modern ICE going 300K miles without much service and replacement parts. With properly lubricated bearings, an AC motor can run 100 years 24/7 with no service, this is proven today in factories. There are no brushes and there is one moving part, the motor shaft. Likely the inverter, cooling pump or other device would fail but a well built inverter should last a long time and they are easy to repair.
Click to expand...

Honda has said that the GX ICE was built to go 1 million miles. :) If you look at my oil after about 10K (recommended oil change), it looks just like new. I've seen oil (never changed) after 180,000 miles in a 100% H2 ICE pickup, and it looks just as clean as when it went in.
Click to expand...

Synthetic oil? Normal oil breaks down over time were the 180K miles done in a year? Just as clean and never changed. Was that your car or one you were sure never had the oil changed. A miracle. Honda parts don't usually last over a given number of miles and it's not 300K, miracle parts as well. NG and gasoline are very different as well.
 
My last car went only 240k and was running great when I sold it. I have no doubt it would have gone 3/400k
My current truck has just 166k and it may never make 300 because I will soon be putting most miles on the Leaf.
I have no doubt most ICEs today will go 300k.

I have seen many electric motor burn out or need replacement and failure was not from the bearings.
Just saying, I have no idea what the equivelent miles or hours run time would be.
 
smkettner said:
My last car went only 240k and was running great when I sold it. I have no doubt it would have gone 3/400k
My current truck has just 166k and it may never make 300 because I will soon be putting most miles on the Leaf.
I have no doubt most ICEs today will go 300k.

I have seen many electric motor burn out or need replacement and failure was not from the bearings.
Just saying, I have no idea what the equivelent miles or hours run time would be.
Click to expand...

Could you elaborate a bit on how many electric motors you have seen "burn out" or "need replacement"? What were these motors being used for? how many hrs had they been run, and under what load? What type of electric motors were they? (ie: motors with armature brushes on a vacuum cleaner, or on an electric drill, etc?) Let's not compare apples & oranges here. :?
 
Induction drill press motor, pool pump motor, sump pump, commercial air conditioner motors, clothes dryer.
OK they do not all live in in a perfect environment and niether does the Leaf.
Maybe it was a sub component failure and surely Leaf has some of those things also.
Maybe it is a bad comparison but the previous post about lasting 100 years is stretching it a bit IMO.
 
smkettner said:
My last car went only 240k and was running great when I sold it. I have no doubt it would have gone 3/400k
My current truck has just 166k and it may never make 300 because I will soon be putting most miles on the Leaf.
I have no doubt most ICEs today will go 300k.

I have seen many electric motor burn out or need replacement and failure was not from the bearings.
Just saying, I have no idea what the equivelent miles or hours run time would be.
Click to expand...


An AC traction motor?
 
smkettner said:
Induction drill press motor, pool pump motor, sump pump, commercial air conditioner motors, clothes dryer.
OK they do not all live in in a perfect environment and niether does the Leaf.
Maybe it was a sub component failure and surely Leaf has some of those things also.
Maybe it is a bad comparison but the previous post about lasting 100 years is stretching it a bit IMO.
Click to expand...


An AC traction motor is not the same as the components you have mentioned. And there are many industrial AC motors that just keep running, these are well built and the bearings are kept lubricated, not cheap Chinese vent motors. Cheap air cooled and mass produced motors fail for many reasons. It is a fact that EVs are far more reliable and require far less maintenance than ICE motors. Any ICE can go a long time but I would like to know how many repairs were made on these 200K plus engines. No belts, distributors caps, etc. I have rebuilt plenty of cars and I don't buy 200K miles on oil changes alone, possible but rare. And my neighbor has a bug with 1.2 million miles on it but it has had many an engine rebuild and other parts, it's an old one:)
 
EVDRIVER said:
smkettner said:
My last car went only 240k and was running great when I sold it. I have no doubt it would have gone 3/400k
My current truck has just 166k and it may never make 300 because I will soon be putting most miles on the Leaf.
I have no doubt most ICEs today will go 300k.

I have seen many electric motor burn out or need replacement and failure was not from the bearings.
Just saying, I have no idea what the equivelent miles or hours run time would be.
Click to expand...


An AC traction motor?
Click to expand...


Siemens guaranteed their traction motors for some insane hour run time, I can't remember the figure but it shocked me the gave such a warranty. Traction motors are (some) build to high specs, low cost ac motors are so poorly built they have a design life. I have several AC motors from pre 1920 that still work great and had much use on vents and machinery. I even have a mixer form 1920 that still works great. I suppose hydro generators are replaced yearly?
 
True, for motors that run 24/7. The most strain on an electric motor comes when it starts, from the in-rush of current that also puts a mechanical strain on the windings.

One would expect that a motor that is intended to be starting and stopping all the time would be appropriately designed, but there's always going to be the odd motor that is not assembled quite right, or has a weak spot in the insulation, that is going to fail sooner or later as the stresses flex the windings and inevitably wear out the weak spot.

EVDRIVER said:
With properly lubricated bearings, an AC motor can run 100 years 24/7 with no service, this is proven today in factories. There are no brushes and there is one moving part, the motor shaft.
Click to expand...
 

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