http://www.buchmann.ca/article28-page1.asp

". . .
Another safety issue is cold temperature charging. Consumer grade lithium-ion batteries cannot be charged below 0°C (32°F). Although the packs appear to be charging normally, plating of metallic lithium occurs on the anode while on a sub-freezing charge. The plating is permanent and cannot be removed. If done repeatedly, such damage can compromise the safety of the pack. The battery will become more vulnerable to failure if subjected to impact, crush or high rate charging.
. . ."

Understand that I like the potential energy densities of LiON cells as much as anyone else. But the current cells have not only a well documented high temperature limit due to a potential, run-away, self-discharge (aka., "venting with flames") but there appears to be a risk on the cold side too. I just learned about this from Electronic Design News that referenced this source.

My thinking is LiON cells have their own cell challenges and we need to keep a healthy skepticism . . . until we can get engineering samples of new technology cells. After all, we are pretty much seeing the hydrogen hype running out (at last.)

Bob Wilson

 

You could engineer a system that would keep the battery warm, in its own environmental chamber, and also prevent any charging if certain parameters (temperature) were not met.

Harry

 

Well, the short-term solution is "don't do that." Toyota's engineers have already placed significant restrictions on the charge/discharge rate of the NiMH batteries used in current generation products when temperatures are at or below 0C. You are allowed to use the pack to start the engine, but assist and regen are both limited until it has been heated to above freezing either from the slight internal heating at low current or, probably more efficiently, from cabin heat. Try to start up in EV mode on a lightly modified '04+ model after a good cold soak and the car just beeps and says "Uhh, no, not gonna do that." So given those observations I do not see anything different about using Lithium Ion technology in the limited capacity to which we are accustomed.

Serious obstacles are conceiveable when you change this application to that of a plug-in, and expect it to be chargeable year-round anywhere in North America. You must assume the worst case scenario of someone allowing the car to cold-soak outside and then plugging in the extension cord. Frankly, I don't know what you do about that except for heating elements on or in the pack.

This could be what the execs are talkign about when they say "We don't have the battery technology for a plug-in hybrid." It might be that the capcacity is there as many of us believe, but the capacity isn't there under all conceiveable conditions.

 

The new LiIon chemistries are fine from -40oC to +60oC, which is the temperature range demanded by the automotive industry.