Plug-in Hybrid Future: Andy Grove get it!

Agreed. I've seen sea water eat aluminum and it's alloys for lunch, there are some challenges. And we're kind of setting up shop in someone else's house (fish, whales).

Expect resistance.

 

Astute point. But I don't think the differences would necessarily be very large. A hybrid battery allows for more efficient use of gasoline but a PHEV battery allows for substitution of other fuels for gasoline. If the critical shortage is oil, then it's not immediately clear that using a given amount of battery capacity as hybrids would save much more oil.

Here's a numerical example.

For battery size, let me take the Hymotion Prius converion as the template: 5 KWH added to the stock Prius ~1.5KWH battery. But the Prius pack is never fully used. Call it roughly 4:1, PHEV battery size to hybrid battery size. I could believe a larger ratio of both were Li-ion.

For hybrid performance, let me take the Escape, which is the best comparison of an optimized HSD versus straight gas version of the same car. Mileage there is 32 hybrid and (I cheat a bit) 24 straight gas with manual transmission. The gas savings per hybrid amounts to one-fourth of the consumption of one regular ICE Escape.

If the PHEV were used as an EV (ie, electric miles only), the net impact on oil consumption from one PHEV Escape (displacing one ICE Escape, with zero oil use) would be about the same as four Escape hybrids (displacing four ICE Escapes, using three-quarters as much oil each.)

Either way, the net impact of building one PHEV Escape or 4 hybrid Escapes is to reduce oil use by one ICE Escape's worth.

Admittedly I slanted the numbers. But my point is that it may not be too wasteful to put the batteries into PHEVs. If the rate limiting factor is as much consumer acceptance as it is manufacturing capacity, then the more products available, the better.

And, for sure, when Toyota puts a Li-ion battery into the Prius, they ought to let it be charged off the grid, for however many miles it's worth. Just 5 miles of PHEV capacity would cover 12% of US drivers' vehicle miles, based on US DOT data. A 1.5 KWH Li-ion battery ought to give that much range in a Prius.

 

As mentioned before, electric generation capacity is not the problem. Our power plants are sized to meet the maximum instantaneous load demands placed on the system. Even in places where the grid is stretched thin at peak, there is a huge amount of surplus capacity available the rest of the time. To start with, you can probably get by on the fact that most people will tend to charge their cars at night just out of practicality. Eventually you will need a smart charger that knows how much strain there is on the grid and acts accordingly (maybe even giving power back to prevent brown/black outs as in the V2G proposals). Given those requirements there have already been studies to show that most if not all of our light duty vehicular transport could be transitioned to electric without building more power plants.

As far as batteries, I think the answer is simple. Federalize Chevron/Texaco's large scale vehicular NimH patents, and setup government funded large volume production facilities. Li-ion is a great technology, and will probably be one of the keys to eventual long range PHEVs and BEVs, but in the mean time they are overkill for first gen PHEVs and are slowing implementation and increasing cost.

For example, here are the pack weights and volumes for a 5kWh pack similar to the Hymotion:

Ovonics/Cobasys 9500 NimH (late 90s, large scale NimH used in EV1 & others):
1.234 cu ft, 194.4 lbs
http://www.cobasys.com/pdf/transportation/Series9500Brochure.pdf

A123 Li-ion 18650 cells (as used in Tesla)
0.821 cu ft, 118.4 lbs
Product Information - Batteries Servos & Accessories for Electric Flight available at BRCHobbies.com

Its a whole different story when you go to 50kWh BEV packs, but for the small packs needed for first gen PHEVs, I just don't see that there is any need for Li-ion. Is 76 pounds and 0.41 cu ft really going to make or brake the design? In the mean time the Li-ion are much more complicated to deal with, less mature, and much more expensive.

Putting a solar array on your roof, you could drive a Prius sized EV 15,000 miles per year for 1.7-2.1c/mile and that rate is fixed for 20-25 years. Compare that to 8.7c/mile for a Prius at $4/gallon, or 18.2c/mile for an average 22mpg car. Compared to putting gas in a Prius, and assuming gas only stays at $4 per gallon and assuming your solar only lasts 20 years the annualized ROI for the upfront cost of the solar is 10.5%! With gas going up 5% per year, and the solar lasting 25 years its 24.8%!.

Rob

 

NiMH won't last long enough as a PHEV, if the batteries are run through a full charge/discharge cycle every day. Cobasys claims "more than 1000" 80% charge discharge cycles before failure. That would be 3 years of daily PHEV use. NiMH will work for full EV batteries, where you'll seldom run the battery down to full discharge in a day, but they aren't durable enough for PHEV use. I think the next-generation Li-ion (or something equally durable) is necessary for PHEV.

 

All rechargeable batteries have the exact same problem, whether it's NiCd, NiMH or LiIon.

The solution is simple - increase the size of the battery and don't charge/discharge the cells as much, just like they do with every hybrid's batteries today and they are doing with the Tesla, they are planning to do on the Volt, etc.