Yes, battery prices appear to be continuing their long-term decline rate of 7-10% per year. The Reuters article below indicates that consumer li-ion is going for $300/kWh: that's 25% less than several years ago. Please note that consumer devices have the advantage of large volumes, but their size is small and costly. For instance, an iPhone has a 5.3 watt hour battery. The Volt's battery pack at 16 kWh is 3,000 times as large. So, when the Volt gets to 25k vehicles per year, that's equivalent to 75M cell phones (a little more than Apple sold in 2011). That's pretty good scale.
http://in.reuters.com/article/2012/07/11/autos-batteries-idINL2E8IB5UT20120711
On the other hand, individual cells for automotive uses are much larger, which is cheaper to manufacture (per unit capacity) and can use cheaper materials (because weight isn't nearly as critical).
The bottom line: automotive traction batteries will stay cheaper than consumer batteries (which will continue to fall in price, driven by intense pressure from places like Apple).
2) The overall price of an EV is a very complex mix, and can't be reduced to the cost of the battery. Car makers have many costs: drive train; ancillary devices such as steering and braking; suspension/wheels; body (including aerodynamics); etc. Almost all of these have to be redesigned for an electric drive train (which includes EV/HEV/PHEV/EREV) because the design requirements are very different. For instance, ICE vehicle efficiency is dominated by weight. Weight is much less important for EVs because they have regenerative braking, so aerodynamics move strongly to the forefront. Another example: elimination of mechanical control and power transmission (brakes, steering, etc) affects a lot of secondary systems. Heck, window wipers get redesigned!
Battery packs are complex: there are the individual cells; the connections; cooling and heating systems (air and liquid); charge and discharge management systems; temperature sensors, heat insulators and radiators; electronic communications and control, with hardware and software (including 10M lines of code, more than recent fighter jets); containment systems, structural support and crash protection; etc.
So, economies of scale apply to the whole car, and cost comparisons are complex. That's why I raise the example of the Prius C, which has the advantage of Toyota's economies of scale and willingness/ability to aggressively price a new vehicle based on long-term costs before it has achieved the large sale volumes which will enable those low costs.
A Prius C has both ICE and electric drivetrains, each of which are sufficient to drive the vehicle. That's substantial duplication. And, they have a full battery pack (with battery management), yet they can price the vehicle starting at $19k. We can get a pretty good idea what a small PHEV could cost, based on that. Of course, we have a plug-in Prius for the purpose of analysis, but it's larger, and IMO Toyota isn't pricing it quite as aggressively because it's newer tech (e.g., it uses li-ion), and Toyota is very careful with it's roll-out rampup of new tech (especially lately, with it's recent quality failures).
The Ford quote is a good example of this complexity. Look at the range of costs: 12k-15k! Ford's purchasing guys know the battery cost to the penny, so that tells us that Mulally is including a lot of stuff in that figure, and signalling to us that the line of inclusion is very fuzzy. The alternative is that Mullally doesn't know anything about the EV program, which seems unlikely to me.
3) I think everyone in the car industry is agreed that li-ion is the future. On the other hand, Toyota can be paradoxically conservative, and NIMH has worked quite well for them, so they're going to transition away from it slowly. For instance, the main Prius and the C continue to use NIMH, but some new versions like the plug-in, and the V (in Japan and Europe) are using li-ion.
A final note - I don't think oil prices will stay above $150 for an extended period of time any time soon. I used hyperbole in my last post to point out the cost effectiveness of EVs (including all their variations), so that we can all be clear that suburbia is not threatened by PO (for better or worse).
