Will there be issues with more battery cycles, and short cycling engine?

I've only had my 2017 Prius Two Eco for 6 weeks, and it's working great, love the car but there are some things that make me wonder about long term durability.

The battery really cycles a lot on every trip. As I understand it, the previous Prius' didn't switch to electric motor mode very much, and the Gen 4 seems to switch to EV mode a lot. We live in a hilly area, and while driving 55 mph down the road, the engine shuts off on every downhill. On a 20 mile trip I'll see the battery go from very full to almost empty several times. The nickel metal hydride batteries in the old cars had a good reputation for long life, so I'm wondering if there will be a life sacrifice from all the cycling on the new batteries. Only time will tell I guess.

The other thing I wonder about along the same lines is the engine turning on and off a lot even before it gets warmed up. My old school thinking was that the most wear occurs during engine startup. Also, I guess they must have figured it out, but every time the engine shuts off, especially when cold, you'd think the exhaust catalyst would cool off and increase emissions.

Not really expecting any answers to these questions, but it sure would be fun to talk to Toyota engineers to hear how they tested or addressed them.

 

I'm hoping that's the case with the battery, and I'm most definitely enjoying the car. Just wondering if compromises were made relative to the previous battery tech, which most would agree probably exceeded reliability expectations.

Regarding engine cycling, my car definitely shuts off before being warmed up. On a 50 degree F morning, I pull out of my garage, it usually starts right away, continues to run for 0.4 mile at 20 mph, continues to run at the first stop, then only runs about 0.3 miles at 35 mph, before shutting off as I coast to the next stop sign which is only 0.9 miles from where I started. Of course there is no coolant temp gage, so don't know the temp for certain, but other cars with gages required at least 3 miles of driving at highway speed to reach operating temp. I'm going to assume the slippery oil and the rest of the design has been tested for this probably very typical condition, but just wonder how they're pulling it off, especially regarding catalyst temp.

 

No real worries, more interested than concerned. I haven't had an earlier Prius, but my son has a Gen 2, and when he tried mine out he said my car uses EV mode way more than his, like for example at 55 mph with light load.