Multiple choice - What could GM do to increase EREV sales? Ideas? (2nd try)

They really really gotta explain what the hell the thing is. Now, before starting to roll out the variation on other model platforms. The dual nature of the Volt/PHEVs is a real understanding gap in the general public, and I think the public would really welcome the key concepts of "You only put gas in it when you go a long distance, which makes it faster than even fast charging. Otherwise, just smooth quiet power with even less maintenance."

Once you start branching out into the different platforms, THEN you can hammer on the details that take advantage of the quirks of the drivetrain: The PHENOMENAL starting torque of a 150kw electric motor for towing/load hauling in a PHEV truck. Being able to drive an Equinox for about a nickel a mile in fueling costs over the course of a year at average electric rates, and that it gets BETTER in the city.

The whole fast charge thing for a PHEV really feels like overkill to me. There's good grounds for a 7kw Level 2 capacity, but it's reasonable to keep in mind that figure of "95% of trips out from home fall under this many miles" is still a good range for a PHEV and the vast vast majority of charging is gonna be in one's own garage or at a workplace, where a sub 4-hour time to full isn't really a huge improvement precisely because this is a PHEV, and alternatives exist. And it's really easy to stick 25kwh under the cargo floor of a crossover without even raising the passenger floor. and leaving the folding seats flat across the whole back, which should be enough for typical daily driving of even a Suburban.

JRRF said:

The Voltec system is a marvel, but it's far from refined or simple. Making the system an order of magnitude simpler (which for example would get rid of half the theoretical discussions on this board, and make the average IQ salesman look like he knows what he's talking about)

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To put it simply, the complexity of the system isn't really important. It works, there's nothing that a driver needs to or could do anything with, to, or about it, and as long as people are willing to immediately turn to trained professions if it fails (and the vast majority of people are), then the complexity exists only in a sealed box and isn't relevant. And we see that expressed in reduced operational complexity (Voltec vehicles could easily exist with a self-setting parking brake and transmission lock and a "D-N-R" selector) and drastically reduced maintenance requirements. (For example, annual tuneups, coolant flushes, transmission fluid changes are gone. Quarterly oil changes are gone. Weekly liquid fueling gone. Those things are 5- and 10-year, bi-annual and monthly or quarterly tasks now. A thousand dollars of maintenance costs or probably 40 hours a year of shade-tree labor has been reduced to what could end up a $300-a-year deal with some dealership/3rd party service contract for hybrid/Voltec/powertrain work that's still a profit for the firm offering it. Presuming there's enough market penetration to keep the work flowing, that is. The THEORETICAL arguments we have here are just that: theoretical. We can't influence most things, and those we can (when to use L vs pedal vs paddle, whether to use cabin heat or seat heaters, when precisely to force air recirculation, all that nonsense) doesn't really matter that much because it'll only add a mile or to of range that we're probably not using to get to the grocery store and back anyway. It's fun, but it doesn't accomplish much at all.

So the vehicles ARE simple on the outside, where it matters. Compare that to (for example) steam locomotives, which are simple on the inside (it's nothing but a container to boil water in, and steam pressure is used to move a couple of pistons) but complicated on the outside. You've got a fire to maintain, by hand. You've got a boiler level to check, by hand. You get to (by hand) adjust the timing of the steam injection into the cylinders and how much. There's 20 different lubrication points that need to be addressed every eight hours or 200 miles of operation, whichever comes first. You need to descale the boiler, clean buildup off the inside of the firebox, and check everything for corrosion several times a year. The steam goes to at least two and usually about six small turbines to supply power for lamps (via turbine generators) and pumps (getting more water INTO a boiler at pressure is a job, unless you want to stop every 20-50 miles, wait six hours for thing to cool and depressurize so you can add more water, then spend four hours heating it back up again) and compressors for braking. It's a tremendous amount of work, for the simple engine.

I'll take the complexity on the inside, thanks...

jlsoaz said:

I have been wondering - if DCFC is moving toward higher kW (maybe 50 kW on a decent CHAdeMO station back when I had a Leaf, but that looks to be improving), and if the Volt offers less than 20 kWh usable (my 2013 only seems to use 10.x kWh for each drive but I don't know about Gen2) then maybe the charge time on a Volt at a DCFC could get down to as little as 10 minutes using present tech, and even less in the future.

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The trick is that battery charge rates are kind of limited by chemistry. Lithium Ion batteries should never be charged faster than in 30 minutes, from "empty" to "full" (actual capacity, not including state of charge buffers at the top and bottom end). That's a "2C charge rate" -- twice the capacity of the battery per hour. Going faster is very hard on their eventual useful number of charge cycles, even with good thermal management. Keeping the charge rate below 1C (an hour from "empty" to "full") gains about 30% MORE charge cycles to end-of-life. And limiting to 0.5C charge rates add another 15% to the expected cycle count or so. Plus, you can actually get more electrons in before "full" at slower rates. A battery that takes 100kwh at some small fractional C might reach "full" by voltage after only accepting 85-90kwh at 2C, and there's nothing you can do at that point. There's only 85 in there so you've lost 15% of your range being in a hurry for that charge. Slow charges, slow discharge, avoiding deep charge/discharges and good thermal management is how Volts take batteries that usually only last for 1000 cycles and push them to 5000-6000 cycles and warranty the batteries for eight years. (Twice a day charging for eight years is 4380 cycles.)

jlsoaz said:

Hi - someone mentioned that they see this as good information, and it does seem like it, but are there any additional sources we could reference on some of this? And, are you saying it is all-encompassing (across all chemistries, thermal management, charge management, etc.) or are there exceptions? Just for one example, would Toshiba's recently announced improvements look like they could be an exception (or perhaps some batteries would not be considered conventional lithium ion and so not fit the rule?.... or perhaps some other consideration such as insufficient testing as yet?)

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Best single source for all this is http://batteryuniversity.com/learn/

You're correct with the implication that not all lithium ion batteries are the same. When most people, me included, say "lithium ion", they're talking about normal lithium cobalt oxide cathodes with carbon anodes, and the characteristics I talked about are appropriate for those. Technically, lithium iron phosphate, lithium manganese oxide, etc are all "lithium ion" as well, but LiCo had a half-decade head start and does a lot of stuff really well that the others just don't get a lot of time.

The Toshiba battery is a lithium–titanate battery, and the big difference is that the anode (positive pole of the cell) is a titanium crystal lattice instead of a carbonate crystal, which is strong enough to make an anode with about 25 times as much surface area, and THAT is what makes the faster recharge rates possible. The downside (not mentioned in the greencar article) is that these batteries are rather more expensive than LiCo and are only about 60% as energy dense, due to the cells having a lower voltage. So you need more battery to make a kwh of storage, which is heavier and bigger than the same power's worth of LiCo. A Bolt with the same battery form-factor would probably have only about 40kwh, have a practical range of about 150 miles, but if you got access to a 350kw charger, it'll charge up in 10 minutes.