I found the missing 4" (vertical) in the trunk. It is below the battery.

But if it's for airflow then you'd need an even bigger sink.

 

It's not. The airflow is all inside.

 

Given past Prii experience, I'd put a couple mouse traps under there

 

Or more beer and cold-packs.

Bob Wilson

 

I would assume that the weight is carried at the attachment points and the styrofoam is just to reduce flexing

Looking at the OP's photo it looks like they already designed a shelf for beer

 

Why not have the tire under the car with a winch like on trucks? Ground clearance issues, you already have the jack out.

The engineers were told to design the Prius, and then the Prime based on it. The first ones might of had the battery down in that space, but were smaller capacity, Toyota America wanted more EV range.

 

Yeah that's been my thought too. Not as convenient, but might work. It would likely take some revision of the sheet metal and the gas tank.

 

This is case where the Tesla 2710 cells might be a better solution. I could easily see them densely packed with liquid temperature control in the wheel well. It might be heavier but the increased luggage space would be welcome with a flat floor. In fact, there may be enough of a 'step' to put a flat, 2710 cell pack on top.

Bob Wilson

 

But Toyota didn't want the cost of liquid cooling, or the Prime would already have it.

 

It has two:

• engine
• transaxle - now using the transmission oil instead of the earlier model coolant system

My BMW i3-REx has a liquid cooled and heated battery. This makes a lot of sense as it avoids the problems we saw with the Gen-1 Prius. Weak terminal seals and marginal air cooling led to a lot of early problems that only subsequent, better designed battery modules could mitigate. But I have no doubt that liquid cooling and heating could of mitigated those problems and likely avoided the battery failures.

Bob Wilson

 

Both of which run hotter than you want the battery, and are also both within the engine bay, close to the radiators. The battery will need its own circuit that is plumbed from the front to the rear of the car. I think that liquid thermal control is superior, but it does add to the cost of the car. Possible enough that some Prime sales would have remained Prius ones instead. If you don't want the Prime MSRP going up, then any fix to the packaging is going to have to stick to air cooling.

 

Even though powered air cooling takes place inside the battery, I would think that there would be some additional benefit from making it easier for the external battery case to shed heat to the surrounding air. Maybe not much in comparison to the internal cooling but still helpful. Although that would only work if the empty area below the battery allows convection, with openings above where warm air can escape from, and openings below where cooler air can be drawn in. Or of course an actual fan blowing through the area, but that would still require some type of entry/exit for the air. If the empty area does not have any real ventilation then it would be mostly useless as the warmed up air would have nowhere to go. Also you would expect to see something resembling fins on the bottom of the battery, maybe shallow ones but at least something to increase surface area. However the bottom of the battery seems to be flat and smooth. So you may be right that this has nothing to do with battery cooling, and is just a square peg - round hole situation that for whatever reason they decided not to deal with, at least not in the current version.

Besides cost I would think liquid cooling would add weight, perhaps not much but maybe enough to have to cut somewhere else as they seemed to be fighting to keep the weight down.

 

Your definition of "inexpensive" is rather vague and country oriented. The Prime is $40,000+ in Canada. Oh, wait, we can't buy one (yet) so I guess it's priceless.

 

And of course they would had passed that cost along.

In the end everything is a compromise with money being one of the biggest factors. But somehow I don’t imagine the design team just woke up one day and said “oops we left 4” do space”. After all they could have doubled the price and called it a Tesla.

 

Or just donuts.



Seriously though, the Prime is grossly lacking in secret hiding places. This might be a good location, if someone figures out an easy access method.

 

to feed the mice?

 

I might be saying something completely wrong and please correct me if I do but...

Could it be that the battery is raised to help avoid it from being punctured from the underside? If it's lower to the ground like it is for a Tesla, they'd have to build the battery carriage differently?