carolle
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Weight of battery and cabin space

Fri May 17, 2013 6:24 pm

(1) What is the weight of lithium-ion battery pack? Or, what would be the weight of the batter per kWh?

I've heard that Tesla's big capacity battery (60~85kWh) takes so much weight, which enforced other materials such as doors to be lighter materials.

Given that 1 gallon of gas gives 20-30 miles for a conventional car, it means that 6 lb of energy gives 20-30 miles. Of course, when considering the weights of all necessary parts for internal combustion, the required weight should be higher. But, I'm wondering whether current technology has limitations on the weight of the battery.


(2) I love LEAF very much. But, I was surprised that there was no visible improvement of the cabin space, which can be easily seen in Tesla Model S. Okay, LEAF is much cheaper than Model S, so it's not fair to compare :)

But, the protruding part in the middle of rear seats is hard to understand. Also, there are many bulky structure in the front center cabin area, where the shift is placed.

The reason actually can be understood by the chassis:
http://www.mynissanleaf.com/viewtopic.php?f=15&t=18" onclick="window.open(this.href);return false;

Is there a fundamental challenge to make the battery pack flat for larger cabin space, just like Model S?

thankyouOB
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Re: Weight of battery and cabin space

Fri May 17, 2013 6:27 pm

4322 pounds.
google bing whatever is your friend.

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Last edited by thankyouOB on Fri May 17, 2013 10:20 pm, edited 1 time in total.
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DeaneG
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Re: Weight of battery and cabin space

Fri May 17, 2013 6:29 pm

The Leaf's battery is a mostly flat rectangle somewhat similar in shape to the one in the Tesla S.

The Model S has up to about four times the battery capacity of the Leaf, much higher cost, and is much larger. They are not comparable cars, any more than how a Honda Civic compares to a Mercedes S-Class.
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carolle
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Joined: Mon Apr 08, 2013 1:34 pm
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Location: San Jose, CA

Re: Weight of battery and cabin space

Fri May 17, 2013 9:40 pm

thankyouOB wrote:4322 pounds.
google bing whatever is your friend.
No, 4322 pounds is not the weight of the battery. LEAF is 3291 pounds. The batter can't be heavier than the car :)

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TonyWilliams
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Re: Weight of battery and cabin space

Fri May 17, 2013 9:43 pm

carolle wrote:
thankyouOB wrote:4322 pounds.
google bing whatever is your friend.
No, 4322 pounds is not the weight of the battery. LEAF is 3291 pounds. The batter can't be heavier than the car :)
24kWh - LEAF battery - 660 pounds (300kg)

50kWh - Rav4 EV Gen II - 850 pounds

85kWh - Tesla Model S - 1450 pounds

KJD
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Re: Weight of battery and cabin space

Fri May 17, 2013 9:53 pm

Just for comparison, the Lead-Acid battery pack in my home built Toyota pickup was close to 1800 pounds and the range on my truck was a lot LESS than the LEAF range.
http://www.evalbum.com/3175" onclick="window.open(this.href);return false;
3175c.jpg
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Nubo
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Re: Weight of battery and cabin space

Sat May 18, 2013 12:34 am

carolle wrote:Given that 1 gallon of gas gives 20-30 miles for a conventional car, it means that 6 lb of energy gives 20-30 miles.
Yes, the energy density of gasoline is very high -- around 12,000 Watt-hours per kilogram.
But, I'm wondering whether current technology has limitations on the weight of the battery.
Not sure how recent this chart is, but it gives you an idea ...
Image
I love LEAF very much. But, I was surprised that there was no visible improvement of the cabin space, which can be easily seen in Tesla Model S.
To me the LEAF interior space seems quite good for a car its size.

Is there a fundamental challenge to make the battery pack flat for larger cabin space, just like Model S?
The LEAF battery is modular so it could be any number of shapes. The current shape was chosen to work with other aspects of the design and maximize interior space for a small hatchback to still carry 5 adults with a decent cargo space. Making something flat doesn't make it any smaller.
I noticed you're still working with polymers.

Yogi62
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Re: Weight of battery and cabin space

Sat May 18, 2013 7:20 am

roughly speaking, I've been equating a gallon of gas as 10 KW/h. The leaf has a "2 gallon" tank that is relatively bulky and does not go down in weight as I use it. Think about this, the tank on my '92 suburban was 42 gallons and fit behind the axle under the deck. That's a 420KW/h tank that weighed about 300 lbs full and 30 lbs empty.

With BEV's there is a big weight penalty for carrying around extra batteries that you don't use every day. Could They have put another 6KW in the leaf by filling in part of the trunk or an extra layer of batteries in the floor, but the weight would be even worse. I could probably get by with a 12KW pack if I had reliable charging at work.

kovalb
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Re: Weight of battery and cabin space

Sat May 18, 2013 7:21 am

carolle wrote:(2) I love LEAF very much. But, I was surprised that there was no visible improvement of the cabin space, which can be easily seen in Tesla Model S. Okay, LEAF is much cheaper than Model S, so it's not fair to compare :)

But, the protruding part in the middle of rear seats is hard to understand. Also, there are many bulky structure in the front center cabin area, where the shift is placed.

The reason actually can be understood by the chassis:
http://www.mynissanleaf.com/viewtopic.php?f=15&t=18" onclick="window.open(this.href);return false;

Is there a fundamental challenge to make the battery pack flat for larger cabin space, just like Model S?
I believe your question is actually two parts.

a) "...the protruding part in the middle of rear seats..." was done to cost effectively package the parking brake cable for the 13MY. Electric parking brakes are very expensive, so this was one of the contributors to the price reduction. The parking brake cable has to be laid out in an almost straight path. It is a safety component so no compromises should be made. Unfortunately the battery pack under the rear seat is directly in the way of the cable path at floor level. You would think there would be another solution but there really isn't. That protruding part covers a single cable that runs along one of its edges.

b) The other part of the question has to do with battery pack and vehicle packaging. My opinion is that Nissan chose to do what was necessary to take what they know about existing front wheel drive ICE vehicle packaging and adapt it to an EV. This explains having all the drivetrain components under the hood and the battery mostly under the rear seat (half of it is anyway). This is important if you are trying to quickly make a car that is both cost effective and will pass every safety test (LEAF is an IIHS top safety pick). You use the knowledge you already have. Tesla on the other hand started with a clean sheet of paper and essentially reinvented the wheel. I give them credit, there is a lot involved. Musk once said something like it was easier to put a rocket into space than to make a car.
Had six Nissan LEAFs in five years. Hope to get another.
Retired Nissan Employee (NTCNA-AZ). Opinions expressed here are my own.

mortisier
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Re: Weight of battery and cabin space

Sat May 18, 2013 7:39 am

Sweet lead sled dude!
KJD wrote:Just for comparison, the Lead-Acid battery pack in my home built Toyota pickup was close to 1800 pounds and the range on my truck was a lot LESS than the LEAF range.
http://www.evalbum.com/3175" onclick="window.open(this.href);return false;
3175c.jpg

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