Brammo Owners Forum

General => Off Topic => Topic started by: Richard230 on August 08, 2012, 09:48:15 AM

Title: Battery cooling
Post by: Richard230 on August 08, 2012, 09:48:15 AM
Visor Down reports that Kawasaki has applied for a patent to duct air through an electric motorcycle to cool its batteries.  If this works, I assume that it would avoid the complexity and expense of liquid cooling.  Here is the story:

http://www.visordown.com/motorcycle-news-new-bikes/electric-motorcycle-patent-from-kawasaki/21163.html (http://www.visordown.com/motorcycle-news-new-bikes/electric-motorcycle-patent-from-kawasaki/21163.html)

There is not really much information here but the comments about Kawasaki as a company willing to use motorcycles to showcase their technology is interesting.
Title: Re: Battery cooling
Post by: Brammofan on August 08, 2012, 09:50:53 AM
I wish they had shared the patent application number - I tried to find it and was unsuccessful. 
Title: Re: Battery cooling
Post by: kingcharles on August 08, 2012, 02:19:49 PM
Air cooling will not suffice at the moment which is shown by the problems the Nissan Leaf has in hot areas.
Maybe when batteries can operate at higher temperatures it can become interesting.
For bikes this is even more true because they have less 'skin' around the batteries than cars and when parked in the sun will heat up even more.
That is why such a black box as used on the Zero S is dangerous in my opinion when parked in the sun.
Title: Re: Battery cooling
Post by: protomech on August 08, 2012, 03:18:41 PM
I tested (http://electricmotorcycleforum.com/boards/index.php?topic=2083.msg7182#msg7182) the exterior battery case temperature for my Zero as well as the internal temperature sensors placed inside each battery module.

The highest temperatures I have seen are 105F/41C ambient, battery case exterior 130F/54C. The battery modules report temperatures around 10F lower than the hottest point on the exterior, so 120F/49C.

Zero says the BMS will disable operation at 140F/60C.

A car interior is like a greenhouse, ambient temperatures inside can rise above 150-160F. The battery temperature is probably much lower - I imagine Nissan continues to operate pack fans even when the car is "off".
Title: Re: Battery cooling
Post by: kingcharles on August 12, 2012, 07:36:09 AM
I tested (http://electricmotorcycleforum.com/boards/index.php?topic=2083.msg7182#msg7182) the exterior battery case temperature for my Zero as well as the internal temperature sensors placed inside each battery module.

Thanks, but I cannot view the link.
I get a message that I am banned from the forum  ???
Title: Re: Battery cooling
Post by: Car Loss on August 13, 2012, 08:40:57 PM
Air cooling will not suffice at the moment which is shown by the problems the Nissan Leaf has in hot areas.
Maybe when batteries can operate at higher temperatures it can become interesting.
For bikes this is even more true because they have less 'skin' around the batteries than cars and when parked in the sun will heat up even more.
That is why such a black box as used on the Zero S is dangerous in my opinion when parked in the sun.

This is a joke, right?  Cars trap their low, wide packs inside a shell, between a greenhouse and a pavement surface.  A shell as airtight as possible, above a pavement surface as close as possible, to reduce drag.  Motorcycles, as empirically demonstrated, place their packs above the skin height (air layer  against the ground), with a generally-vertical layout that coincidentally supports convection.  As for color, you're telling me you see in the infrared?

Carlos