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

Maybe the battery that Toyota wanted is behind schedule. The new battery in a couple of years we’ll be four times the power for same size or same power for 1/4 the size.

I well take twice the power for half the size so I can still charge at home at 220 volts.

 

Huh, I suspected that that packaging was the case, but that's atrocious.

It is hard to make a form-fitting battery, though, and they almost certainly didn't want to make a new unibody stamping for the Prime. So, this is the solution they came up with.

I'm going to harp on this again and again, though - a relatively simple shape battery could've fit under the rear seat (and ventilation could work as it does on the Gen 4 Liftback, pulling air from under the seat, with that design), and a complex shape gas tank that goes into the former spare tire well is relatively easy to make. Why didn't they just do that?

 

Two words.
Ford Pinto.
One word
lawsuits.

 

Didn't stop VW or Hyundai.

 

That just means Toyota is smarter, IMHO.

 

i think they didn't do it cause japans solar roof battery got priority.

 

The Golf GTE/Audi A3 sportback e-tron and the Passat GTE have been out for a few years, and there isn't a Pinto-esque scandal. And, with barely any compromise on cargo capacity compared to their ICE-only counterparts, that can help adoption of PHEVs.

I mean, unless Toyota is trying to weaken the Prime's sales by not making it anywhere near as useful as a standard Prius...

Also, Toyota's battery layout bothers me more than Volkswagen and Hyundai's fuel tank layout. The Toyota battery is further back in the car, and a Li-ion battery being punctured almost guarantees a fire, whereas a punctured gasoline tank only increases the risk of a fire. (That's not to say that it's a serious concern, but I'd rather have the battery more protected, especially if it ALSO makes it easier to have good cargo space.)

 

Keep in mind as suggested above the "missing 4-inch" appears to mainly be the indent for the spare tire. The picture I think tends to exaggerate the size of the space in the photo, like holding a small fish on the hook closer to the camera to make it look big.

 

This is a G4 Prius Hatchback. If you imagine laying the battery where the dark gray foam is, I think the gap shown in the OP is mostly the indention for the tire as seen from the back of the car.

 

no - cooling batteries with just air is potentially a greater heat danger. 6Kw does NOT create a lot of heat in & of itself. VW/Audi is in the process of setting up 300+ mile EV infrastructure with 600V - 15 min - 80% recharge times. Even teslas recharge @ 120kW's - so claiming 6kW's is fast can only remotely
be considered 'moderate' if it's compared to 120V - 1kW charging. It's just that charging & discharging at high rates while being encased w/in confined areas necessitates a more expensive / complex thermal management design. Heck - our home's AC pulls ~25% more than 6kW's.

But a residential AC isn't so confined - and has a mongo noisy fan that moves huge amounts of (hot) air. Not the same as a confined battery traveling across a hot desert, but electric appliance / thermal conditions have similar issues to overcome-deal with.

.

 

Not that it's much consolation but it could be worse - the Sonata and Optima plug-in hybrids have their 9.8 kWh batteries in the trunk up against the rear seats, preventing the rear seats from folding down like they do in the regular hybrid versions. Basically crippling carrying capacity, especially for long items.







On the flip side, the Ioniq plug-in (already released in Europe) has its 8.6 kWh battery located under the rear seats, freeing up rear cargo space. The difference with Ioniq is that the same platform was built for electric, regular hybrid, and plug-in hybrid. However this could be why the Ioniq is reported to have less headroom for rear passengers, since the rear seat area has to also accommodate the electric model's 28 kWh battery.

Assuming that Toyota has no plans to make an electric Prius, maybe they could place a reshaped plug-in battery under the rear seat and stick their beloved solar panel batteries in the donut hole, so cars with the solar option don't get a spare tire. Of course they could eliminate the donut spare in all models but I'm guessing that is too polarizing for them to consider that yet

 

I am not exactly sure what your point is. You say air cooling is dangerous, and yet that is how the Prius cools the battery. You also say that 6kwh does not create a lot of heat. To get that 6kwh, you have to put in 8kwh. 2kwh turns into heat. Put a 2 kw electric heater in the trunk of your Prius and run it for an hour. Actually, don't. Too dangerous. That is what the 4 inches is for. I am not sure what your home A/C has to do with the battery heat. A liquid cooled system would be a lot more efficient, but the technical issues and higher cost make it currently impractical.

 

That's not what the 4 inches of gap is for - the Prius vents things to atmosphere.

Also, it takes longer than an hour to charge the Prime (it takes over 2 hours), so even with your example, it'd be a 1 kW electric heater, not a 2 kW one.

But, that example is wrong - the EPA's range and efficiency calculations are based on plug power - at 25 kWh/100 mi, and 25 miles electric range, you're looking at 6.25 kWh of plug power - you're not losing 2 kWh to heat.

 

just checked & there is no such word as "dangerous" in any of my text.

again - no i didn't say that either. The statement referred to amounts of heat in relation to the minimum & maximum that electric cars charge. Heat generated via electricity turns on how much is passing through whatever gauge wire & the appliances ability to handle it. So that whole notion is somewhat of a tangent.

i'm sorry but if you have 220V & multiply the typical 30 amps that gets drawn by a J1772 you get 6.6kWh. If you presume the prius draws 8kW's just to get 6, that would mean the charger has an efficiency of less than 80% - in stead of over 95% & NO EVSE is that inefficient.

it was just an illustration, but if if is not understandable, feel free to presume I'm just incomprehensible & unable to make a decent illustration .... & I can live with that. It's not that I'm impatient to help someone understand illustrations, I just fear that a further illustration might further add to what is apparently confusion

.

 

No, those numbers are totally wrong. To get 5.7kWh, I had to put in 6.3kWh, but that difference is both for charging and for discharging. In reality, most of the loss is during discharging. The battery charging is likely to be over 95% efficient (closer to 99% most likely, if you ignore the charger itself). Thus, a 3.3kW (L2) charge will produce less than 5% or 165W of heat. That's a little more than the heat from one human body, and about 1/10th the heat from a hair dryer. It's less than the heat produced by a desktop PC, which is cooled by a little 5" muffin fan, in many cases. It's nothing, especially when you have to heat up an entire hundred-pound battery (over 200 if you include the container) with that little bit of heat.

 

They said, "That's the best we can do, with what they gave us."

Except there is already a sizable gap between the road surface and the bottom of the metal pan to make room for the muffler and suspension.

I wouldn't blame the engineers. They likely presented better options that were canned from higher up because of costs.

No, the battery Toyota wanted was smaller capacity. Like the PiP's, because they were still thinking home market only. Then Toyota USA told them that would not sell here.

Several car models since the Pinto have placed the fuel tank between the rear axle and rear bumper without issue.

The incidence of fire in the Pinto was within what other cars of the time had. The real problem with the car was its tendency to stall, leading to being rear ended.

Back to the Prime. Honda gets amazing usable space in the Fit by placing the fuel tank under the driver's seat. Why wasn't that an option for Toyota.