The total difference in price between the baseline Prius Plug-in and a Chevy Volt is about $2,100 after the full tax credits…

Chevy Volt 2012 – MSRP: $39,145 – 7500 = $31,645
Toyota Prius Plug-in 2012 – MSRP: $32,000 – 2500 = $29,500
Difference:  $2,145 (does not include any destination charges or other dealer add-on fees)

After realizing this, my initial position of leaning towards the Prius is starting to change back to the Volt because there is only a $2,100 difference in price. The difference goes up to $3,100 if you count the difference in cost between the $1000 base 240V 3.3kW charger for the Prius and the $2000 240V 3.3kW Volt charger. This choice is determined by several factors.

1. Prius top electric speed The Prius plug-in has a top full electric speed of 62MPH, while the Volt is always electric when there is capacity in the battery. For me, this means that my 70MPH commute on the highway to and from work and to and from most of my friends’ houses means I’m using gas in the Prius because of my top speed. In the Volt’s case I’ll always be on electricity if I have the charge? Because of my large amount of highway driving the Volt holds some advantage here.
2. Electric range is 15 miles With the Prius, the electric range is 15 miles and probably lower in cold and hot weather (e.g. most of Vegas weather). My commute is 15-16 miles, most of which is on the highway. So I’m inclined to think I’d have to charge at work in addition to home, so I’d have to work with the building manager to get a charging station.
3. Weird charging port location This isn’t a deal breaker, but it does get under my skin a little – everyone else is putting their charging port up front near the drivers door.  The Prius puts its in the back right. So I’d have to walk around to the back of my car to plug it in twice a day. Plus in commercial shopping centers the charging stations are usually at the front of the car. Do cars always get backed into parking spaces in Japan?

The first seem entirtely plausable, but probably don’t contribue significantly to the bottom line. Redoing the interior can be done in such a way that it does cut costs – replacing the capacitive touch interior with buttons like every normal car out there, shrink the center stack display (keep the width but switch it to 16:10 widescreen instead of 4:3), looking for off-the-shelf parts and adapting designs to them instead of having to order any semi-custom or custom parts (re-using parts from other cars). But I would estimate they probably couldn’t save more than a thousand dollars this way. Moving some of the more expensive features to options (like the Bose audio system) helps too, but its rearranging the deck chairs, its not fundamentally making the technology any cheaper. Moving to mass production helps – when you factor in overhead and capital costs (the machines, training, supervisors, QA, etc), mass production does help spread those costs out over more vehicles, reducing per-unit costs.

That last option – cutting the battery in half – might seem like killing the main purpose behind the vehicle, but it seems a lot more plausible when you consider the use of plug-in stations at people’s offices. Even in the summer, energy usage in the morning hours (before 10A) are still considered off-peak, so you could recharge the entire, smaller, battery before on-peak charges started. Going to a smaller battery would mean that GM would need to alter the characteristics of the battery – more power and less energy storage per kg of battery material. There are two main issues with shrinking the battery pack in this way – the power output of the battery pack and the cycle life. Power output is governed by the rating of the individual cells as well as the number of cells in the pack. The cycle life would have to compensate for the batteries being recharged twice or even three times per day instead of once at night.

Reducing the battery pack would also reduce the federal rebate – from $7,500 to $4,600 ($2500 + $417 for each kWh above 4kWh). If you’re cutting the price by total vehicle price by $10,000 but losing $2,900 of the rebate, your effective cost reduction is only $7,100. However, this would still push the after-rebate price down from $33,500 to $26,400, or the price of a nicely equipped Toyota Prius. The 2012 plug-in Prius is expected to have a price in that rage, but it is unknown if that included the $3,000 rebate or not (its likely it did – I’d estimate the full price of a Prius plug-in at around $30,000).

The sticking point appears to be the battery. GM would need a batter that is more capable that what is available today, but only by a little. By the end of 2012 or sometime in 2013, such batteries will be available and probably have markedly decreased cost over batteries of today (mostly due to the large quantities in which they will be produced – Toyota will likely be using a similar type of battery, but with less stringent requirements since batteries only provide partial power in the plug-in Prius – up to 62mph and normal acceleration).

The success of a 20-mile range model is highly dependent on building a charging infrastructure outside of people’s garages. Offices and shopping centers will need to build the necessary infrastructure to handle vehicle charging, as well as utilities monitoring and managing the charging using the smart grid. But if the infrastructure materializes, why not use it to it’s fullest while accelerating the use of electric vehicles and reducing oil consumption until batteries are cheap and plentiful.

And it’s definitely better than filling up once a week at $4/gal!

* MSRP is only a suggestion – some dealers have tacked on $5,000 or more onto Volt sticker prices because of their limited quantity and uniqueness

The performance of the batteries and the modular design have attracted attention. The 1.5kWh pack weighs 8kg (17.6lbs) and has a volume of 7L, or about 187Wh/kg and 214Wh/L. These figures are both extremely high considering most other batteries have energy-to-weight and energy-to-volume figures below 140Wh/unit. No information in the press release announced a release window for these battery packs.

The raw figures indicate excellent performance characteristics. Attempting to research the cycle life characteristics of the Lithium Nickel Oxide batteries yielded an paper from 1995 (abstract available) had shown a LiNoO2 cathode to withstand more than 1000 cycles with extremely strong performance characteristics almost 15 years ago. The reason that it had not been used previously is safety problems, which Panasonic indicates they have solved by using a metal oxide layer in the battery that will prevent the anode and cathode from shorting out and causing thermal runaway (heat and possibly fire). If the batteries can be proven to be safe, it would be a significant step in improving battery technology.

As far as applications in cars go, the modules are a perfect fit for EVs and E-REVs because they are significantly ahead of other battery technology to date. This would reduce a 16kWh battery from 160kg (100Wh/kg) to about 90kg, and reducing the volume from approximately 140L (114Wh/L) to 74L (almost half the volume). Specific power is said to be comparable to Lithium Cobalt-based cells, however it is unknown whether or not the values scale up commensurately with the increases in Wh/kg and Wh/L – since the battery pack would have about half of the mass and volume, it would need twice the specific power (W/kg or W/L) to maintain the same power output for a given battery weight or volume. This means it would need about 1,200 W/kg (1,500W/L) to provide 110kW of power with 16kWh (90kg/74L) of batteries. If the batteries aren’t able to produce that kind of power, they’ll be relegated to pure EVs, where you could have a large 25kWh pack (80% DoD)  at 135kg/117L and need only 820W/kg and 940W/L. A research study (PDF, mostly in Japanese, but the abstract and charts are readable) on Panasonic Lithium Nickel Oxide batteries from Japan showed specific power between 4,400W/kg and 1,000W/kg (chart, page 4), however those figures quoted a very low specific energy (94Wh/kg), and assuming that specific power would decrease as specific energy increases, it could be estimated that for a SoC between 85% and 30%, the battery with twice the specific energy would have half the specific power, or roughly between 1,200W/kg and 2,200W/kg. This would be suitable for both E-REVs and EVs, however the restrictions on depth of discharge would remain (no expanding of the Volt’s D0D).

As batteries grow in energy density, they’ll become more practical for larger vehicles. Vehicles like the H3E E-REV demo model produced by Raser Technologies would be able to carry fewer battery packs, reducing the weight of electrification – what was probably 30kWh of batteries weighing 300kg could be reduced to about the size and weight of the current Volt battery pack (160kg/140L), which would be easy to “hide” on an H3 or any full sized truck.

Again, since there is no word on the release date and any numbers for how many cells they would produce per year, its still a bit up in the air – definitely not vaporware, but in that gray area between we’ve made demo models and mass production. Even if these batteries don’t arrive for another 3 years, that’s still far ahead of the 5-7% average annual performance increase we’ve had for Li-Ion batteries the past 10 years or so, batteries with this level of performance would not otherwise be expected until 2017.

The 2,000 cycle count is very impressive as well as the high discharge rate, and this battery is well suited for devices like power tools or R/C airplanes. Does this mean anything for electric cars? Not really, since it appears the batteries are cylindrical and not prismatic (rectangular prism). From a volumetric efficiency standpoint, prismatic batteries are better because you can pack them in tightly, where as with cylinders you’ll always have that space between the cylinders.

But what if Sony put this same battery technology into prismatic batteries? Based on the properties of this battery, they would stack up very well for an hybrid car – 1800W/kg and 95Wh/kg would be best suited towards hybrid and plug-in hybrid cars with small batteries and high power demands – a 3kWh battery would be 32kg and provide sustained power of 56kW, with peak power higher than that. The specific energy is too low for any kind of E-REV or EV, and would cause the batteries to be too large and heavy.

[via Sony Insider]

While 2012 is only three years away, Toyota has a firm base on which to develop a PHEV – the Prius. Taking the Prius platform and adopting it to PHEV would require some engineering changes – notably the ability to transfer more of that battery energy to the wheels. The Gen III Prius can output up to 60kW of power through the electric traction drive. Toyota would need to develop a system to expand that number up to about 80kW to allow a Prius to drive at reasonable rates

To get a good idea about what size battery they would need, I consulted a recent Argonne national labs electric vehicle study that showed a car with an 8kWh li-ion battery pack (5kWh usable) would be able to drive for about 15 miles at city driving speeds before using gasoline. This would seem to match up with Toyota’s 12-18 mile target. This 8kWh pack (by 2012) would probably source 1,500W/kg and have a specific energy of 100Wh/kg, and would weigh 100kg with the battery and electronics. Neither of which are unreasonable targets.

The Argonne study indicates that for the average driver, it would reduce fuel consumption by 62% over a conventional vehicle and a 48% reduction over a standard hybrid electric vehicle. This would almost double the MPG of the Prius from the current 50MPG to 97MPG. These figures are dependent on commute distance and driving conditions however – those with longer commutes or more highway driving would likely see reduced fuel economy.

via GCC