Possible Improvements in Regenerative Braking Depth

I know little about the mechanics/electronics of regenerative breaking in the PiP. For those with more knowledge, how difficult might if be to capture more energy with more aggressive braking (not talking about regeneration efficiencies here)?

The reason for the question is that when there is little or no other traffic on the road, I brake entirely within the vehicle’s ability to capture this energy without using the friction brakes. However, often traffic is such that I must brake more aggressively so as not to create angry tailgaters.

For example, if coming up for a turn, instead of coasting then braking slowly, I might come up to the turn faster then have to advance into the friction brakes to safely navigate the turn.

With the current PiP, is this a limitation of the size of the regen brake mechanism, limitation of how intense regen the batteries can take in a short period of time, some combination, or something else entirely?

Might be nice in the future PiP to be able to capture brake regen more deeply without having to use the friction brakes. And in lots of stop and go driving, this would actually increase fuel ecomony.

 

Do the PiP and regular Prius have different tolerances to regen depth*?

For the Volt and Tesla drivers among us who have also driven the PiP, how does regen depth compare?

*By regen depth, this is meant to refer to how aggressively one can brake before transitioning from regen to friction braking

 

Ok, so you are saying battery chemistry plays a significant role. What about the total number of cells/battery capacity? If the next gen PiP were to have double the batter capacity and similar chemistry, could we theoretically have deeper regen with braking?

Anyone who has driven a Volt and PiP notice a difference?

 

Along those lines, thinking more battery capacity would also help with big hill and mountain descents. I've noticed that even in cool weather, I'm not able to aggressively brake regen into the battery longer than a minute or so at a time. It seems here the car switches into engine compression braking for a while, probably to protect the battery cells from overheating.

 

In my case this happens before maximum SOC, when going down high grade long mountain descents and keeping the brake at sustained maximum regeneration. At this rate, the battery starts to recharge very fast (much faster than even a L2 charge).

Perhaps for the first 3-5 EV regen miles, the battery fills without incident. Then about every minute (with the car under 62 mph) the EV logo will vanish and no EV regen miles will accumulate. I assume the PiP to be compression braking at this time.

This will last for 20+ seconds and automatically go back into regen braking. If I continue to brake at max regen capacity, I probably will not get more than another minute of this before being switched back into compression braking. If I brake lighter, I can stay in regen mode much longer.

 

Pretty impressive to stop a 4600+ pound vehicle.