Submitted by danielccc on April 9, 2013
It has been noted that when cold, the regen does not work because the battery cannot take the charge till it reaches a certain temperature. This can surprise the driver, and even if the driver expects it, is an operating inconsistency that the car could do without.
It seems to me that a simple solution under these conditions would be to direct the power from motor braking to a simple heating element. This has two advantages. One is that the accelerator pedal would work the same under all conditions, providing "regen" braking even when cold. The second advantage is that this heating element could be thermally connected to the battery coolant circuit, so the battery would warm faster in initial cold conditions. Some heat would be generated just getting out of the typical parking lot.
A heating element, basically a resistor like that found on an iron, is a very cheap part that would not add much to manufacturing cost. There is some R&D involved for the integration and software, but this seems like a simple yet helpful upgrade for cold regions, improving both driving experience and battery performance.