VIDEO: Prius PHV Technical Video

So no more spare tire, I guess?


Still, really cool. Can't wait to try it in person.

 

I thought the most tantalizing piece of info was "more than 50% of braking energy recaptured."

 

The lack of a spare tyre can be overcome with the use of the puncture repair kit as is currently being used in the top-of-the-range model in Oz and other countries.

One point that I picked up was the notion that the charging cycle would not just be used to recharge the batteries but would also be used to maintain engine and other temperatures at close to operating levels.

 

If the plug-in remote A/C system is a heat-pump-based, how about the non-plug-in?

 

I put together some interesting information from the video and priusphv.com.

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The battery powering the Prius PHV is the first lithium-ion drive-battery developed by Toyota and its joint venture battery production company, Panasonic Electric Vehicle Energy (PEVE). In early November, PEVE began producing the first of more than 500 lithium batteries on a dedicated assembly line at its Teiho production facility in Japan.

This first-generation lithium battery has undergone more than three years of coordinated field testing in Japan, North America and Europe in a wide variety of climatic environments and driving conditions. Using approximately 150 conventional hybrids (mostly Prius), the field test vehicles logged well over a million combined miles. In the end, the battery was deemed both reliable and durable, confirming that it could indeed be used in conventional hybrid applications in the future, depending on further developments in cost reduction.

New HV Battery:
- Holds about four times the charge. Compared to the current NiMH battery, the new Li-ion battery is more powerful, resulting in greatly improved EV performance.
- Higher battery voltage contributes to even better fuel economy in HV mode

The PHV combines the advantages of HVs and EVs
- Worry-free without a limited driving distance

CO2 emission: 62 g/km (non-plugin: 89 g/km)
- Improved EV performance has resulted in even better fuel economy and even lower CO2 emissions

 

anyone catch the typo?

New HV Battery:
Higher battery voltage contributes to even better fuel economy in HV mode.

shouldn't that be EV mode?

 

No typo, that's correct.

You'll see an efficiency boost during non-EV driving too.
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I think it is HV. The Prius PHV should get more than 50 MPG in HV mode, once battery deplete.

The higher voltage of the PHV battery transfer power to the MG more efficiently. The PHV pack can also capture more regen brake.

 

thanks!
You know it wasn't more than a few months ago, Toyota was advertising, "We've been testing lithium for years and we're perfectly happy with the nickel metal chemestry we're already using"
Now you have it ... a complete 180

Ok, I'll bite.

Also ... what's up with "higher voltage" ?? (the video also confirms higher voltage) but they don't say how much higher. Isn't the Prius traction pack already somewhere around 270 volt DC? so are we going up to 440? or what?

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They've got the current pack really well optimized already for HV use. There's not enough bang for your buck without a plug.
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Remember the legal limitation of NiMH batteries? It was a lawsuit that kept them from using a higher voltage. With lithium based batteries, there's new efficiency opportunity.
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Nominal voltage of a NiMH cell is 1.2V; the Prius has 28 modules, each module being made up of 6 cells, so that's 28 x 7.2V = 201.6V. However, nominal voltages are pretty much near-empty cells with a high load - this image shows the actual voltages at each step:



(source)

The nominal voltage of the lithium-ion cell is usually given as 3.6 or 3.7V - different materials for cathode (negative electrode) and anode (positive electrode) give different voltages and lithium-based cathodes are pretty high. Different cathode materials (lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate [LiFePo]) give slightly different voltages but they're all in the 3.3-4.0V range.

We don't know how Toyota have constructed this new battery, but I would expect that it's mostly series construction (positive electrode of one cell connected to the next one's negative, and so on) which adds the cell voltages together. It might perhaps have a few strings of modules in parallel to increase capacity and current.

Why increase the voltage? The cross-section area of cables needed depends on the current that the cable has to handle. For a given power, higher voltage means lower current, means a thinner, lighter cable.

 

I do not see any inconsistency with what Toyota has been saying. They tested Lithium and it was technically feasible. They started looking a way to mass produce cheaply. Li-ion is not price competitive with NiMH yet so they decided to stick with NiMH on 2010 Prius. It sounds like by 2012, mass production of Li-ion will be mature enough to replace NiMH. I expect Sienna hybrid to come out with Li-ion.

At the cell level, NiMH is 1.2V and Lithium is 3.6V so it is 3x more. Current NiMH pack for the Prius is 201.6V but the MGs operate at 650V. My best guess for PHV Li-ion pack would be 650V to match the MGs and eliminate the need to boost/lower voltage. Regen from 650V MG2 to charge 650V PHV pack would be more efficient for this reason.

This page explains the increase of the voltage from the Classic to Iconic model:
http://www2.toyota.co.jp/en/tech/environment/ths2/kouden.html

 

Very interesting to see. I like the idea of the integrated cabin heating. Will they provide an integrated engine block heater too? We warm the cars in the morning during the Maine winter and it would be great to have it done in an efficient, controlled manner. I'm particularly interested in the HV economy improvements from the larger capacity battery and the voltage increase. I just mentioned to my wife how the automotive world will be so different in 2012 with mass-production PHEVs and BEVs. "You're not waiting for two years." I waited for the 2010. I waited again for another reason. Finally test drove one. I'll get one soon. Maybe.

 

so i guess it can only be charged at home, or where ever that charging station is?

 

Non plug-in uses engine coolant since you have to run the engine anyway. Engine exhaust heat recovery helps warm the coolant for fast cabin warm-up.

The battery doesn't have enough capacity to run the heat-pump for extended periods without running the engine, anyway, so I'm guessing the added weight/complexity of the heat-pump over a normal heating system isn't worth it in a normal hybrid.