WSJ: GM moving to Lithium Ion; Li-ion could give Prius 80 mpg

**Danny** · 03-01-2008, 11:07 AM

The Wall Street Journal reports this morning that, along with Mercedes Benz introducing a hybrid that runs on Lithium Ion batteries in 2009 as reported earlier here, GM will be moving their "hybrids" to Li-Ion batteries. Exactly when and the price is unknown at this time.

The article also reports that analysts predict that a Li-Ion Prius could up it's miles per gallon to over 80 mpg.

Continental AG is making the batteries for Mercedes, while Hitachi has been hired by GM to produce their batteries.

WSJ

Tech_Guy · 03-01-2008, 06:29 PM

"Analysts believe a Toyota Prius with lithium ion batteries could go about 80 miles on a gallon of gas, up from about 50 now...."

I'll believe it when I see it. I seriously doubt that changing the battery from Nickel Metal Hydride to Lithium Ion will radically improve overall automobile mileage efficiency . Although Lithium Ion batteries have a much greater storage capacity per unit volume, the efficiency ( energy out / energy in ) isn't radically improved. Anybody out there have any actual data comparing battery types???

Keith

Spectra · 03-01-2008, 09:15 PM

No data here --

But, if the Lithium Battery goes into production, I'm wondering whether it could replace the Nickel Hydride batteries in place, in Prii that are already in use ?

Or, whould it require extensive or prohibitive re-wiring ...?...

McShemp · 03-01-2008, 09:37 PM

Quote:

Originally Posted by Spectra

No data here --

But, if the Lithium Battery goes into production, I'm wondering whether it could replace the Nickel Hydride batteries in place, in Prii that are already in use ?

Or, whould it require extensive or prohibitive re-wiring ...?...

Not likely. The battery characteristics and management system built into the Prius means it will only work with the NiMH pack. Retrofitting existing cars to use a new battery chemistry will likely prove to be too expensive. The only option for LI-Ion in older cars will be for an "add-on", booster pack that isn't charged by the vehicle ... only by plugging in.

Li-Ion packs will make the OEM PHEVs come alive.

dipper · 03-01-2008, 10:35 PM

I don't know about 80 mpg from 50 mpg, but I am certain of improvement in some form even for non-plugin setup. Maybe that is the next Prius that is rumored to have mid-65 mpg without plugin (even with a larger 1.8L ICE).

Why not setup to have Lithium battery to have equal storage/voltage capacity as the NiMH? Since Lithum has more than 90% energy transfer/storage rate compare to NiMH (mid-30%?).... there is your improvement there... plus another 120 lb or so weight saving.

Godiva · 03-01-2008, 10:58 PM

Doesn't Lithium-Ion have a shorter life? I.E. the batteries won't last ten years. And aren't they limited to a certain number of recharges?

I can see Lithium Ion as an additional pack, but not as a replacement for the NiMH.

I think a new battery technology is still coming that give the benefits of both together. I also think it's going to be coming pretty soon given the demand.

Sufferin' Prius Envy · 03-01-2008, 11:29 PM

Quote:

Originally Posted by McShemp

Not likely. The battery characteristics and management system built into the Prius means it will only work with the NiMH pack. Retrofitting existing cars to use a new battery chemistry will likely prove to be too expensive. The only option for LI-Ion in older cars will be for an "add-on", booster pack that isn't charged by the vehicle ... only by plugging in. Li-Ion packs will make the OEM PHEVs come alive.

The "battery characteristics and management system built into the Prius" does NOT mean it will only work with a NiMH pack.

I wouldn't put it past Toyota to design the new Lithium pack to be compatible with existing Prii form factor. If so, all it would require is a software update for existing Prii to take advantage of a Lithium pack, to the maximum physical extent of the existing Prii's capabilities.

RonH · 03-01-2008, 11:50 PM

Quote:

Originally Posted by Tech_Guy

"Analysts believe a Toyota Prius with lithium ion batteries could go about 80 miles on a gallon of gas, up from about 50 now...."

I'll believe it when I see it. I seriously doubt that changing the battery from Nickel Metal Hydride to Lithium Ion will radically improve overall automobile mileage efficiency . Although Lithium Ion batteries have a much greater storage capacity per unit volume, the efficiency ( energy out / energy in ) isn't radically improved. Anybody out there have any actual data comparing battery types???

Keith

"analysts" pfft! Some clueless MBA's who make their living guessing. Reminds me of the tabloid articles that always quote "Swiss scientists" about two headed aliens. Nice work if you can get it, but does anybody take them seriously. Oh, wait. isn't Chelsea an analyst?

ronhowell · 03-02-2008, 12:33 AM

Quote:

Originally Posted by Tech_Guy

"Analysts believe a Toyota Prius with lithium ion batteries could go about 80 miles on a gallon of gas, up from about 50 now...."

I'll believe it when I see it. I seriously doubt that changing the battery from Nickel Metal Hydride to Lithium Ion will radically improve overall automobile mileage efficiency . Although Lithium Ion batteries have a much greater storage capacity per unit volume, the efficiency ( energy out / energy in ) isn't radically improved. Anybody out there have any actual data comparing battery types???

Keith

Me too. Where do people think this additional 30MPG is going to come from? Simply changing the traction battery pack from NiMH to Lithium ion merely changes the electrical storage medium - it has no inherent energy content, as does gasoline. While Lithium ion batteries exhibit electrical storage capacity up to twice that of NiMH, thus enabling longer EV range ability, that energy has to originate somewhere. Having to replace the additional electrical energy in the battery pack will consume more gas, so the MPG may even decrease, since these energy exchanges involve inherent inefficiencies. The questions of cost, temperature stability and weight have also to be considered for a viable system to evolve.

Only by providing plug-in capability to the next generation Prius does the Lithium ion battery make sense, either by re-charging from solar arrays by day, or from the grid overnight during periods of minimum power station draw.

rah

drees · 03-02-2008, 04:02 AM

The only way a Li-ion battery (or any other battery) would improve performance is:

1. Lower internal resistance so can handle higher charge/discharge rates. Being able to accept higher charge rates means that you can use regenerative braking more instead of having to augment braking as much using the friction brakes. Higher discharge rates (along with a motor that can handle those rates) mean faster acceleration on battery power alone is possible.

2. Lower internal resistance so less energy is lost when charging or discharging (charging/discharging becomes more efficient).

3. Better weight/energy storage ratio. You could use the same capacity battery and reduce weight of the vehicle which improves efficiency, or increase capacity to give you more room to charge the battery now that you can capture more energy while braking.

I highly doubt that economy would increase from 50 to 80 mpg because of a battery upgrade, unless that battery upgrade also let you plug it in to charge it.

03-01-2008, 11:07 AM	#1
Danny Admin/Founder Join Date: Nov 2003 Location: Charlotte, NC Posts: 5,561 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 78 Thanked 339 Times in 144 Posts Friends: 42	WSJ: GM moving to Lithium Ion; Li-ion could give Prius 80 mpg The Wall Street Journal reports this morning that, along with Mercedes Benz introducing a hybrid that runs on Lithium Ion batteries in 2009 as reported earlier here, GM will be moving their "hybrids" to Li-Ion batteries. Exactly when and the price is unknown at this time. The article also reports that analysts predict that a Li-Ion Prius could up it's miles per gallon to over 80 mpg. Continental AG is making the batteries for Mercedes, while Hitachi has been hired by GM to produce their batteries. WSJ __________________ Follow PriusChat on and *Buy your discounted 2010 Prius Accessories* here and support PriusChat: PriusChat Shop PriusChat Also Offers Discounts on: Extended Warranty - $1055 : Pre-Paid Maintenance - $875**

03-01-2008, 06:29 PM	#2
Tech_Guy Class Clown Join Date: Jan 2007 Location: Silicon Valley, Ca. Posts: 624 My Car: Other Non-Hybrid Model: N/A Package: N/A Thanks: 199 Thanked 61 Times in 40 Posts Friends: 0	Re: WSJ: GM moving to Lithium Ion; Li-ion could give Prius 80 mpg "Analysts believe a Toyota Prius with lithium ion batteries could go about 80 miles on a gallon of gas, up from about 50 now...." I'll believe it when I see it. I seriously doubt that changing the battery from Nickel Metal Hydride to Lithium Ion will radically improve overall automobile mileage efficiency . Although Lithium Ion batteries have a much greater storage capacity per unit volume, the efficiency ( energy out / energy in ) isn't radically improved. Anybody out there have any actual data comparing battery types??? Keith

03-01-2008, 09:15 PM	#3
Spectra Amphi-Prius Join Date: Feb 2008 Location: S NJ Posts: 3,120 My Car: 2008 Prius Model: Package: #2 Thanks: 34 Thanked 15 Times in 15 Posts Friends: 8	Re: WSJ: GM moving to Lithium Ion; Li-ion could give Prius 80 mpg No data here -- But, if the Lithium Battery goes into production, I'm wondering whether it could replace the Nickel Hydride batteries in place, in Prii that are already in use ? Or, whould it require extensive or prohibitive re-wiring ...?...

03-01-2008, 10:35 PM	#5
dipper Senior Member Join Date: May 2005 Posts: 603 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: WSJ: GM moving to Lithium Ion; Li-ion could give Prius 80 mpg I don't know about 80 mpg from 50 mpg, but I am certain of improvement in some form even for non-plugin setup. Maybe that is the next Prius that is rumored to have mid-65 mpg without plugin (even with a larger 1.8L ICE). Why not setup to have Lithium battery to have equal storage/voltage capacity as the NiMH? Since Lithum has more than 90% energy transfer/storage rate compare to NiMH (mid-30%?).... there is your improvement there... plus another 120 lb or so weight saving.

03-01-2008, 10:58 PM	#6
Godiva AmeriKan Citizen Join Date: Apr 2005 Location: San Diego, CA Posts: 10,340 My Car: 2005 Prius Model: Package: #1 Thanks: 0 Thanked 1 Time in 1 Post Friends: 7	Re: WSJ: GM moving to Lithium Ion; Li-ion could give Prius 80 mpg Doesn't Lithium-Ion have a shorter life? I.E. the batteries won't last ten years. And aren't they limited to a certain number of recharges? I can see Lithium Ion as an additional pack, but not as a replacement for the NiMH. I think a new battery technology is still coming that give the benefits of both together. I also think it's going to be coming pretty soon given the demand.

03-02-2008, 04:02 AM	#10
drees Senior Member Join Date: Oct 2007 Location: San Diego, CA Posts: 1,032 My Car: 2008 Prius Model: Package: #2 Thanks: 355 Thanked 90 Times in 73 Posts Friends: 1	Re: WSJ: GM moving to Lithium Ion; Li-ion could give Prius 80 mpg The only way a Li-ion battery (or any other battery) would improve performance is: 1. Lower internal resistance so can handle higher charge/discharge rates. Being able to accept higher charge rates means that you can use regenerative braking more instead of having to augment braking as much using the friction brakes. Higher discharge rates (along with a motor that can handle those rates) mean faster acceleration on battery power alone is possible. 2. Lower internal resistance so less energy is lost when charging or discharging (charging/discharging becomes more efficient). 3. Better weight/energy storage ratio. You could use the same capacity battery and reduce weight of the vehicle which improves efficiency, or increase capacity to give you more room to charge the battery now that you can capture more energy while braking. I highly doubt that economy would increase from 50 to 80 mpg because of a battery upgrade, unless that battery upgrade also let you plug it in to charge it.