lorenfb wrote:johnlocke wrote:edatoakrun wrote:It would have been an odd decision, IMO to add either liquid cooling or pack insulation to the 2018 LEAF.
Even more bizarre, would be to add it to only some of (the likely lower production volume, higher capacity pack versions) the 2019 LEAFs.
Adding either feature is relatively trivial from an engineering standpoint, though very expensive in terms of production cost and efficiency.
If Nissan saw any benefit, why did it not add either or both features to the 2018 MY?
So, while anything is possible, until a high integrity source reports otherwise, I think we should expect Nissan to retain passive thermal management, primarily utilizing conductive cooling, in all 2019 MY LEAFs.
Either or both pack designs could use suppplementary active air cooling, much as some other BEV manufactures have, which is very low cost, but provides minimal benefits in terms of reducing battery temperature.
I'd regard blowing air from the standard AC system over the cell cases as mainly a placebo for those suffering from capacity loss anxiety, but it would allow Nissan to tout this benefit, to those misinformed buyers for which it could be appealing.
Air cooling via internal fans would be relatively cheap to do and have a minimal drain on the battery. Even a small airflow will remove a surprising amount of heat. MIght not help much while driving but could certainly help during charging. Could also cool down the battery while parked particularly overnight. It would have to be better than sitting in stagnant air trying to cool. I suppose that you could even vent into the rear passenger compartment for a little extra heat in the winter and dump it outside in the summer.
It depends how the battery is mounted/attached to the vehicle's chassis and the thermal resistance between
the battery and the chassis. If the thermal resistance is effectively zero, then the fans must also cool the
vehicle's chassis to cool the battery.
The battery is bolted onto the chassis. There aren't any thermal transfer pads and the battery is a sealed unit. The chassis is probably cooler than the battery anyway. The only reason that Nissan didn't implement cooling for the battery is cost. They are using the same battery casing and chassis to save money. Probably short-sighted on their part since it looks like the failure rate on the 16-17 30KWH batteries is going to be higher than the old 24KWH batteries. The 40KWH batteries are likely to have even more heat problems just because they will charged for longer periods and are capable of higher current draw(150 HP motor). There are rumors that the 60 KWH battery will require a TMS just for that reason.
My point was that regardless of the details, fan cooling would still be better than just leaving the battery sitting in still air and trying to cool itself by convection. If you could implement an air tunnel through the center with heatpipes to transfer heat from the battery stacks to the tunnel that would be even better.