Battery Life or Cycles on PHEV?

In theory if your doing 100% charge/discharge cycles you would have say 70% capacity left after 3000 cycles. Charge cycles have been tested but no one knows the shelf life of the lithium batteries yet since they are still new.

 

It would only go 10 miles instead of 14.

The Sanyo/Pansonic battery that Tesla will be using, is good for 3,000 to 5,000 deep cycles. The prototype PHV Prius uses about 67% (lets call it PHV cycle) for every time you drain it (14 miles). That's not very deep. I should be able to get at least 6,000 PHV cycles.

PHV Prius does not use laptop cells like Tesla but rather prismatic cells. It should be more reliable than the cylindrical cells.

 

If Toyota is only using 67% of the SOC then in theory you would have 14 mile range for the life of the car but the total energy storage of the battery would drop to 80-70% after 3000-5000 cycles. Only when the actual battery capacity is less than the usable SOC range will you see a decrease in EV miles. I would expect by then the car would throw some codes.

 

I don't think the car will throw some code. I think it will continue to function with lower range.

The code should throw only for unusual / unexpected issues, such as voltage of a cell is dangerously low.

 

Until we know the battery chemistry toyota will use, we won't know how charging will affect it. IMHO there is no way they will just put the same batteries in the production car.

For Lithium batteries in general time spent undercharged or overcharged and sitting in heat are the main killers. FWIW toyota tends to be conservative so charging the batteries twice a day will keep them in the healthy range. Will you have less battery life than someone charging once a day, sure, but it won't go linearly with cycles. If the battery is designed for 10 years once a day charging, it will probably do 8 years twice a day charging. But note again, I don't know what battery toyota will eventually put in the car.

I would hope toyota would throw a code if the charged capacity went too low. I don't even know what capacity our prius batteries are warranted for. So its likely no code so toyota avoids some warranty work.

 

Actually the cycle life is pretty linear according to what Jack Rickard posted on the subject. Of course the cell was LiFePO4 from CALB.
EVTV.ME: Life in LiFePo4 - Cycle Life and Attenuation Data

Scroll down a bit and you will see the graphs. The batteries were only tested to 500 cycles so its kind of hard to determine what happens after that but if you follow the line it pretty straight.

 

Hi Force,

You can't tell anything from that test. The phv prius vehicle will have a much gentler charging cycle. You can not tell the difference with aging at all, and the aging effect is significant. 10 years daily will cause more battery degredation in all lithium chemistries that I know of than 5 years twice a day. Increasing the cycles is much easier than making the battery last more years.

 

You would have to do the arithmetic, but how about two LEAFS ? Run each one about 80 miles a day.

 

Did I guess wrong that your driving radius is fairly circumscribed ?

 

I think it would be fascinating to model a 2 LEAF taxi setup vs other alternatives for your driving because of the high cost of fuel. Do you or your company keep detailed trip data ?

It would easy though to exclude the idea if ideal conditions were still a money loser: Assume 100 EV miles a day, 365 days a year. How much petrol money would be saved a year ?

 

Now THAT is what I really hate too. You're one person. You can only drive one car at a time. Why can't the person be insured instead? If they want to recalculate rates based on the safety of the car, which would be logical, they could do it with the least safe car you drive. Then you could insure each car separately based more on the actual miles driven. The way it is now, you're paying double for your insurance as the driver with two cars, triple with three, etc.

Then there is the additional license tax for each vehicle, which ultimately forced me to give up my Honda Rebel 250 motorcycle. Even the little Rebel couldn't compete with the Prius, especially now that it has the Hymotion kit installed.

And for GrumpyCabbie, I would think the Hymotion kit would be even better than the plug-in Prius. You can get it now, you've already got the Prius too. I would think if necessary it can be switched to another Prius, but that would be some work. The range is more like 20 miles electric rather than 14 with the Plug-In Prius. Also, one trick is that you can, if you know you're going further than the electric range, get the car into the super-efficient gasoline mode and still see over 99.9 mpg for probably 40 miles or so, although I can't give an exact figure. It is virtually impossible to get to that mode in a regular Prius, and the Plug-In Prius won't allow that either, so instead you'll go 14 miles on no gasoline and say 26 miles at 50 mpg, or about 77 mpg, instead of potentially getting 99.9 mpg or more for the entire 40 mile trip. If you're just going low-speed city driving, you can potentially stay in EV mode the entire 20 miles with the Hymotion kit too. Otherwise the engine just comes on for a slight time, and with proper driving you can switch back to electric mode, although I'm not sure if the engine is still somehow still running but not showing up on the display.

 

I don't think PHV or EV make sense for taxi. Taxi operates almost the entire day (multiple shifts). Charging time = down time = money loss.

Isn't there also a licensing fee or medallion cost for taxi? Two Leaf would require twice that startup cost since I don't think it can transfer from one car to another.

Well, there is an exception. Project Better Place's swappable battery EV has been testing in Japan with the taxis.

 

Nice thread.. good ideas expressed.