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?

WLC, in a recent press release, also stated that their target for their stage I lens production is 27,700 metric tonnes per year of Lithium Carbonate (LCE, or chemically Li2CO3). The math to turn that into the number of EVs is easy – 27,700 metric tonnes is 27,700,000 kg of LCE. In 1kWh of a Lithium-Ion battery there is 0.6kg 0.9kg of LCE (figures in this article have been updated). This means that 27.7M kg of LCE per year is about 30.8M kWh of batteries that can be produced. They have an expected 18 years at this rate of supply to mine (approximately 500,000 metric tonnes LCE total).

In a pure EV (like the Nissan Leaf) the battery is 24kWh, so from 27,700 tonnes of LCE comes 1.28M Nissan Leaf battery packs per year. In a EREV like the Chevy Volt, its battery pack is 16kWh, so 1.9M battery packs would be able to be manufactured for the Volt.

To put these numbers in perspective, in 2009 there were a total of 10.4M cars sold in the US, and in 2008 approximately 13M cars sold. So this single lithium mine could power up to 15% of all the US EVs and EREVs sold, if the automakers could build and sell that many (which they wont, at least initially).

So the question is, how many tonnes of LCE would it take to make every car sold in America a plug-in? From a small two-mode system that would allow for 8-12kWh batteries for 10-15 miles at speeds below 60MPH, all the way up to pure EVs with 50kWh batteries. If we assume that 70% of cars sold are two-mode at 10kW, 20% are EREV (18kWh) and the last 10% are pure EVs (35kWh avg), the total kWh for a year of 14M cars is 197.4M kWh, or 177.3M kg of LCE. So in order to produce enough LCE, we would need to produce about 180,000 metric tonnes of LCE, or about 6.5x the amount of stage I.

The stage II lens has approximately 1.365M tonnes of LCE, and at 180,000 metric tonnes per year, it would be exhausted after 7.5 years, assuming the production rate could be sustained.

Seven and a half years might not be a long time, however there are still several other stages to this mine area (stages three and four), plus there are other lithium mines in the Nevada and the US. It appears that Lithium supplies wont be a blockade on the road to electric cars. While Li-Ion batteries can also contain other precious metals that might be scarce, Lithium shouldn’t be an issue.

[Update 5/27 - updated Lithium math based on Leaf's use of 0.9kg/kWh]

The ultra-capacitor is designed to store small amounts of energy (small compared to regular batteries) but are able to receive and put out large quantities of energy quickly. The ultra-capacitor unveiled here can store 14Wh of energy, about three times your iPhone battery. You can see that one or two of these alone wont be able to push a 2,000 lb car very far. So you would put many of these together to form an energy capture device. When you brake, the ultra-capacitor is charged, and when you start again, the stored electrical energy is used to propel the vehicle.

With many of these, you would build a small battery, about 1000 Wh or more depending on vehicle size, and then charge and discharge them. These particular ultra-capacitors could deliver 50kW of energy, which would be enough to propel a small sedan up to 40MPH. They wouldn’t be able to provide for all-electric driving, since a usable 500Wh of energy could only provide about 2 miles of range, but it would create a new range of super-hybrids that could very efficiently provide for acceleration on residential and side streets.

They are designed to put up with the stop-and-go driving, since the initial demonstration units lasted for 2,000 cycles before losing 20% of their capacity. It is likely that this will be worked on and improved up to 10,000 cycles to be suitable for hybrid vehicles.

Mitsubishi has not announced a production time table.

Via Green Car Congress

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

I’ve covered the batteries in question before, I believe they are Hitachi cells specifically designed for hybrid vehicles. They have different characteristics than the LG Chem cells used in the Volt. For hybrid vehicles you carry a small amount of storage (2-3kWh) and pull energy out of the battery quickly to accelerate and to store it quickly when braking. The Volt needs a higher specific energy (storage) while these hybrid batteries need high specific power (horsepower).

The batteries that GM is likely to get have a specific power of around 2,250W/kg. The PDF I link in the above article shows a 3kWh Li-Ion pack, 47kg and 1.4 cubic ft. This would provide for a total power of 90kW (120HP) in an area 41″ x 12″ x 5″. Being able to accept and output that much power could allow the vehicle to drive up to speeds of 35MPH on electricity alone (depending on car weight and other factors). However it is unlikely that GM would use this configuration – their mild hybrid systems only provide 20HP. The minimum battery pack for this size would be about 500Wh (or 8 of the above cells), and a larger 1kWh pack would be able to provide twice that (28kW/40HP).

All other mainstream hybrid vehicles currently use NiMH batteries, which are not as capable of high power output as lithium-ion batteries are. The switch to Li-Ion batteries would not only increase power output (allowing higher all-electric mode speeds), but also a lighter, smaller package. The 3kWh module mentioned above could even power the vehicle at all electric speeds for a few miles (again, depending on vehicle weight, etc).

Cost could be an issue, as these batteries are more expensive than their NiMH counterparts. Lithium-ion batteries command a cost between $800-1000/kWh, while NiMH batteries cost around $200-300/kWh.

via GM-Volt

Ford and Hydro Quebec both stand to benefit greatly from this research endeavor.

Ford will get to test their PHEV technology in a cold climate. One of the issues with Li-Ion batteries is their ability to function in cold climates. Certain types of Li-Ion batteries fare better than others, however there is some point at which they all need a little warm up to be able to provide power. In either case, the vehicle will need to be hooked to a block heater, or the engine will run and generate some electricity to warm the battery pack. The program is already being tested in a much more temperate climate: southern California.

Hydro Quebec gets to further a technology which will increase their revenues through higher power consumption. HQ states that if one out of every four passenger vehicles in Quebec were to switch to plug-in technology, they would see increased consumption of 3TWh per year, or about 500MW of hydro generation turbines.

The Ford Escape PHEV is a parallel hybrid – this means that the electric motor and gas engine combine to move the vehicle. This is not the same as the Volt, which is a serial hybrid, where the gas engine turns a generator to power the wheels.

The Escape PHEV can go up to 30 miles at under 40MPH on electric power. Once over 40MPH the gasoline engine kicks on to supplement the power the batteries can provide. After the batteries are depleted it reverts to a standard hybrid mode. There is no mechanism to recharge the on-board batteries from gasoline.

Ford states that the vehicle can get up to 120MPG however this is highly dependent on driving techniques. If you’re above 40MPH you’re still using some gasoline (though probably not as much as you would otherwise). This is probably because the current Li-Ion batteries cant source enough power to move the vehicle. As batteries improve their specific power and specific energy, this speed will move up, and eventually the entire vehicle will be able to be powered on batteries only in a serial hybrid configuration.

Ford also states that the battery will take 6-8 hours to recharge. At 110V/15A, thats between 10 and 13kWh. At 30 miles, its an energy efficiency rating of 380Wh/mi (which doesn’t seem too terribly efficient, I would have expected low 300s). Assuming a 50% depth of discharge, it would be a pack size of around 22kWh. At 100Wh/kg and 400W/kg, thats 220kg of batteries and 88kW of power. My V6 Escape has a 124kW (171hp) engine, though I would assume the curb weight of the PHEV escape would be higher than the standard configuration (possibly 600-700lbs more).

Via ABG

Argonne National Labs has been pumping out simulation data for E-REV, Hybrid and PHEV cars for a while now, and they’re becoming the primary source of information as to whether or not vehicles like the Volt will be successful in production, and at what cost.

The data used was collected in 2005 by drivers in Kansas City study involving 100 people monitoring their driving habits. From there, six vehicle models were used – a conventional car, a gas-electric hybrid, a hybrid plug-in with 4kWh or 8kWh of energy storage (electric only up to a certain speed, electric plus engine after that or after charge depletion), and two serial hybrids (E-REV) at 12kWh and 16kWh (30 and 40 mile variants).

The first thing that got my attention in the report was the MPG figures (also listed as liters per mile in the report) – the conventional gasoline car got 36.7MPG, the 16kWh E-REV that used 88% less fuel than the conventional counterpart (6.4L/100km vs. 0.79L/100km), which is about 300MPG. The 12kWh E-REV got a fuel economy of approximately 163MPG, the 8kWh PHEV got 94MPG and the 4kWh got 70MPG.

The payback time numbers however paint a different picture. At 9c/kWh and $4/gal, ignoring residual value and maintenance, the cost of the vehicle plus fuel is 8-12.5 years for E-REVs and about 8 years for the PHEVs. Its a little depressing when you remember the battery is only warrantied for 10 years.

This isn’t to say that PHEVs and E-REVs will fail. Rather the approach is to target those who drive just enough to deplete the battery’s charge. The folks who use just enough of the cheap electricity and very little or no gas. And given the small number of production units for the first few years (until about 2015) it shouldn’t be an issue to find those who would achieve a rapid payback time on the vehicle, or who have the money and are willing to pay a green tax. As prices come down, so will the payback time and the market for whom E-REVs and PHEVs makes sense for expands. By 2020 when the cost of adding a 20 mile PHEV in a power split configuration is $4000 and a 40-mile E-REV is $7500, the market will be sufficiently large assuming gas prices continue on their highly volatile trend.

(from Green Car Congress)

The specifications include replacing the NiMH with a Li-ion pack that would allow the Prius to drive further on only electricity. How far? We don’t know. If we compare the size of the Gen III NiMH pack and assume the Li-ion pack is the same size (NiMH 1.3kWh at 200Wh/L or 6.5L), an equivalent volume Li-ion pack would offer about 2.1kWh and 50kW in a low energy-high power configuration (2000W/kg, 85Wh/kg, 25kg battery pack). At a 80% depth of discharge, the battery pack would provide about 7.5 miles of electric only driving, though that assumes that you stay below the 50kW threshold when driving – the electric only range might go from under 25mph to under 45mph for the first few miles while the battery has sufficient charge.

If the Prius doesn’t get an upgraded electric motor and sticks with its 50kW (67HP) motor, then the acceleration will be poor, however it will be capable of highway speeds (though on steep grades it might have some trouble and the engine will kick on regardless of the state of charge).

This is the logical evolution of the parallel hybrid paradigm, but its also the end of the line for the configuration. At some point using the gasoline engine and the electric motor in parallel loses out to a serial configuration because the electric motor is big enough and the battery pack can generate enough power as to only need the gasoline motor in a “power boost” situation, you might as well just not carry that weight for that purpose and carry the weight for a charge sustaining mode.