Comments on: Are the Volt Prototype Packs Running Too Hot? http://gm-volt.com/2008/01/01/are-the-volt-prototype-packs-running-too-hot/ Real-time news, information, and discussion about the Chevrolet Volt. Thu, 24 May 2012 22:53:35 +0000 hourly 1 http://wordpress.org/?v=3.3.2 By: Modifications Electronics Engine Management Systems http://gm-volt.com/2008/01/01/are-the-volt-prototype-packs-running-too-hot/#comment-29204 Modifications Electronics Engine Management Systems Thu, 31 Jan 2008 07:57:07 +0000 http://www.gm-volt.com/2008/01/01/are-the-volt-prototype-packs-running-too-hot/#comment-29204 <strong>Engine Management...</strong> My engine management light has come on and car is kangaroo jumping, any ideas what is wrong?... Engine Management…

My engine management light has come on and car is kangaroo jumping, any ideas what is wrong?…

]]> By: AES http://gm-volt.com/2008/01/01/are-the-volt-prototype-packs-running-too-hot/#comment-24216 AES Fri, 04 Jan 2008 00:21:41 +0000 http://www.gm-volt.com/2008/01/01/are-the-volt-prototype-packs-running-too-hot/#comment-24216 As far as I know the operating temperature for the LiFePO4 or manganese cells is good enough so that the electrolyte won't freeze. But yes initial performance would probably suffer. Flash heating for instant performance after starting up would probably be best accomplished using something electrical rather than liquid-based. A heat pump operating in the winter would probably have its external coils periodically freeze up anyway (not much ambient heat). We'll see what GM comes up with. As far as I know the operating temperature for the LiFePO4 or manganese cells is good enough so that the electrolyte won’t freeze. But yes initial performance would probably suffer. Flash heating for instant performance after starting up would probably be best accomplished using something electrical rather than liquid-based. A heat pump operating in the winter would probably have its external coils periodically freeze up anyway (not much ambient heat).

We’ll see what GM comes up with.

]]> By: Jim I http://gm-volt.com/2008/01/01/are-the-volt-prototype-packs-running-too-hot/#comment-24203 Jim I Thu, 03 Jan 2008 23:23:21 +0000 http://www.gm-volt.com/2008/01/01/are-the-volt-prototype-packs-running-too-hot/#comment-24203 AES #36: The batteries giving off heat while in operation is not in question, so they would need cooling of some type, and we have been told it is a liquid cooling system. The problem is when it is below freezing outside, and we go to use the vehicle. Unless the battery pack is kept warm, the performance will be terrible. For example, this morning my garage temp was about +40F. When I got to work at 8:00 AM, it was +8F. The high temp for the day was +22F. Right now, at 6:15 PM, it is back to +16F. The car has not been run all day and it was outside. Without some warming of the pack, I would be concerned about what effect the cold would have on the battery pack. I assume that the engineers have worked out, or are working on this set of conditions. AES #36:

The batteries giving off heat while in operation is not in question, so they would need cooling of some type, and we have been told it is a liquid cooling system.

The problem is when it is below freezing outside, and we go to use the vehicle. Unless the battery pack is kept warm, the performance will be terrible.

For example, this morning my garage temp was about +40F. When I got to work at 8:00 AM, it was +8F. The high temp for the day was +22F. Right now, at 6:15 PM, it is back to +16F. The car has not been run all day and it was outside. Without some warming of the pack, I would be concerned about what effect the cold would have on the battery pack.

I assume that the engineers have worked out, or are working on this set of conditions.

]]> By: AES http://gm-volt.com/2008/01/01/are-the-volt-prototype-packs-running-too-hot/#comment-24200 AES Thu, 03 Jan 2008 22:53:37 +0000 http://www.gm-volt.com/2008/01/01/are-the-volt-prototype-packs-running-too-hot/#comment-24200 I'm a big proponent of having few moving parts as well, and there are probably already rudimentary heat sinks built into the battery modules, if not the cells themselves. I have some photos of the 35kWh battery packs that A123 built for Orion hybrid buses, and the cells are housed within thin metal module cases that also seem to act as heat sinks (although don't quote me on that). They seem to do that systems' active cooling using large fans and generous space for airflow. Regardless, if they've got the Volt's liquid cooling system in place, they've got the capability for heating as well, although I think you're right that the cells might produce enough heat on their own to be happy on a cold day. I’m a big proponent of having few moving parts as well, and there are probably already rudimentary heat sinks built into the battery modules, if not the cells themselves. I have some photos of the 35kWh battery packs that A123 built for Orion hybrid buses, and the cells are housed within thin metal module cases that also seem to act as heat sinks (although don’t quote me on that). They seem to do that systems’ active cooling using large fans and generous space for airflow.

Regardless, if they’ve got the Volt’s liquid cooling system in place, they’ve got the capability for heating as well, although I think you’re right that the cells might produce enough heat on their own to be happy on a cold day.

]]> By: Tagamet http://gm-volt.com/2008/01/01/are-the-volt-prototype-packs-running-too-hot/#comment-24142 Tagamet Thu, 03 Jan 2008 17:08:07 +0000 http://www.gm-volt.com/2008/01/01/are-the-volt-prototype-packs-running-too-hot/#comment-24142 AES "Complexity" is one of those highly interpretable terms. In this case, I was thinking in terms of "moving parts". I totally agree that a heat pump could work well, I was thinking in terms of a more passive approach, like the heat sinks on computer chips that get VERY hot and are also in an enclosed space. The heat sink coupled with a tiny fan (one moving part) is very efficient too. Granted, a heat sink wouldn't help warm a seriously cold battery but that half of the equation might be handled by a little bit of the battery's own "juice" (again, with no moving parts). Fewer moving parts would imply less weight, too. Especially when a heat pump's compressor is part of the solution. Whatdayahthink? T AES

“Complexity” is one of those highly interpretable terms. In this case, I was thinking in terms of “moving parts”. I totally agree that a heat pump could work well, I was thinking in terms of a more passive approach, like the heat sinks on computer chips that get VERY hot and are also in an enclosed space. The heat sink coupled with a tiny fan (one moving part) is very efficient too. Granted, a heat sink wouldn’t help warm a seriously cold battery but that half of the equation might be handled by a little bit of the battery’s own “juice” (again, with no moving parts). Fewer moving parts would imply less weight, too. Especially when a heat pump’s compressor is part of the solution.
Whatdayahthink?
T

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