High rate charging is not good for battery life. Tesla even cautions the supercharger is for occasional use. As you noted the problem is heating leading to metallic lithim plating...it's exponential with temp. There are curves for this on existing threads. The cut to the chase question is how often would you use fast charging, say rather than waiting 4 hours for level 2.

What company is doing the modifications?

 

I don't think there are a sufficient number of DC chargers to have real world data. It's also going to be dependent on the chemistry. The A123 cells are apparently more or less impervious.

 

It's not unique...it's a characteristic of lithium ion chemistries...faster charge, higher charging voltage to get higher charging current means resistive heating. Lots of data....A123 batteries have been in DeWalt power tools which e-bike hobbyists have been playing with for years. An extreme case is li ion use in model airplanes.

I recommend The Battery Handbook, David Linden Ed. for techs and engineers.

For immediate reference:

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries



Notice the correlation between their curves and what GM did with the Volts battery. Academically, the lowest C is best.

 

Where does Tesla say that supercharging is for occasional use only.

I asked a Tesla rep at the Santa Monica 3rd Street Promenade Tesla store if supercharging had any effect on battery life and she said absolutely not and that you could supercharge every day without affecting battery life.

 

Is the Tesla Rep a sales or a chemical engineer?

 

If battery deterioration due to fast charging is a result of excessive heat, can the Volt TMS mitigate the problem or even eliminate it?

 

Yes, the TMS will mitigate the problem, and the Volt's battery design is very good for cooling with each cell sharing a full surface area with a cooling plate. Because the heat is generated internally, not externally, there still may be localized hot spots. It's not a one time thing, it's that you will reduce available ion density over time by plating.

Whoever is modifying the Volt would have to bypass the 3.5 kw inverter and the BMS software to prevent tripping the disconnects and the Volts software is not a shade tree operation. If it's a 30 minute 20kw rate, from one of the inductive pair startups trolling for VC, it probably will require GM 's participation.....e.g. as an option on a new car. ELR?

Tesla only supercharges to ~60%. In the Volts case 60% is ~25 miles vs. 150 with Tesla.

GM went with the ICE to avoid BEV charging issues.

 

Now that a company has demonstrated that they can fast-charge a Volt, the question arises - should we do it?

Sorry, there is no means to fast charge a Volt, the charger is part of the car, at best your confusing this with the up coming Spark EV

 

Actually, there is a means of fast-charging a Volt.

http://gm-volt.com/2012/12/18/momentum-dynamics-of-suburban-philadelphia-demonstrates-fast-wireless-volt-charging/

 

The Volt fast charges itself in Mountain Mode.

 

I have noticed this as well. When in mountain mode, it looks like the batter gets 30% charge in about 20 mins. Not sure those numbers are exactly correct, but it does seem to charge faster when in mountain mode.

 

This is not a GM approved charge method and the 10K kit would bypass the on board charger by directly connecting to the HV bus. No one in there right mind would install this and I would expect GM to sue to stop it was it could be a fire hazard and libaility for gm. GM doesn't do software upgrades let alone allow a third party battery charger for certification reasons, one Volt fire and it will be all over for both GM and Momentum Dynamics.

Its nothing more than a publicity stunt to show that high energy levels can be transmitted wireless, something that's been done for over 100 years using transformers. As another posted, its Momentum Dynamics trolling for $$ with a publicity stunt, its not and will not be a listed ( UL ) or approved ( Feds and or GM ) option for the Volt.

 

or approved ( Feds and or GM ) option for the Volt.

What Fed department would they have to seek approval from?

 

Slapshot, It does charge in MM.. It stops at 42% SOC. Someone with a Dash Daq probably knows the storage rate to that SOC. You probably are hitting a design limit there.... Mine usually takes about 15-20 minutes from the bottom so 12kw?

You can get even more short term input from regen on a steep slope. I did 3000 feet and got about 2.7 kWh in 20 minutes or 8.1 kw...so it doesn't say much other than that was not pushing the battery.

Key here, and I always wondered why, is MM stops at a low SOC.

 

This (Fast charging the Volt) sounds like a problem looking to beget another problem.

 

Their website doesn't appear to have had any regular updates since Feb 2012, but they were apparently active in June for this conference:
https://s3.amazonaws.com/automotiveworld/slides/cvmusa2012/Andy+Daga+-+Momentum+Dynamics.pdf
http://www.automotiveworld.com/videos/alternative-powertrain-technologies-current-trends-in-wireless-power/

 

I believe its NHTSA, this is the reason GM doesn't for example put new software features via updates from newer models to older ones. One has to certify that any change to the car doesn't effect the required standards that the car was certified with. One would have to prove for example that bypassing the cars internal charger doesn't effect any items on the NHTSA list for compliance. brakes come to mind as the car has regenerative braking and touching anything that modifies that system would require certification, And of the control systems, since there all integrated is similar.

I'm sure many could argue what should and shouldn't covered, that's a very grey area and why GM doesn't provide anything but what is minimally necessary for software changes.

 

I'm sure that GM certifies the many software changes they do make for safety or other reasons and GM doesn't even get paid for that effort.

GM does not sell software enhancements for marketing reasons. It's in our interests as Volt owners and innovators to change their minds.

 

I was not asking if quick charging a Volt was legal, ethical, or moral. People have been modifying their cars for over 100 years and they have been hacking into software before it was called hacking.

I wasn't even asking if the one-time demo setup will ever be packaged for ordinary Volt owners.

My question was whether it would significantly hurt the battery of an EV with a TMS.

 

yes it would. It is not theory, it is chemistry of all current battery technologies. Someone posted a reference before in a previous post. For a car like the volt, I don't see much reason to do it on stock cars, but maybe you have a special requirement.

 

While it may be true that they were able to charge a Volt at more than 3.3kw... It might have cost them 3 million dollars to replace the Volts internal charging system and pay GM to re-write all of the battery management firmware to allow it to happen...

Are you willing to pay an extra $3-5K for an inductive charger?

Are you willing to risk the HUGE electro magnetic field exposure. Love to see the YouTube video of that Craftsman Tool chest flying across the garage when the charger comes on. ;-)

 

Thanks, folks, for the great comments.

The system could require the Volt to be directly above before turning on. The J1772 plug does something similar now.

The field could be shaped to point at the car.

I already paid over $10K extra for an EV, I'd pay another $3-5K for an inductive fast charger and I think others would. The 80+ amp drain on my electric feed might upset the electric company, but I would warn them in advance and pay for an extra doghouse for my house if required.

I think that they spoof the Voltec software the way the CIA did the Iranian centrifuges. They disconnect the real HV battery and sensors during charging and present a simulation. If GM modifies their software to detect this, the lawsuit would be interesting.

BTW, does anyone have a link to the details of the electrochemical effect on the HV battery of fast charging, assuming the TMS handles the heat.

BBTW, I don't think there is any regulation of aftermarket mods to motor vehicles. Think doubly stretched limos, jacked up SUVs with dangerously high centers of gravity, and kids replacing their mufflers with resonators.

 

Here is a link.

http://www.mecheng.osu.edu/nlbb/files/nlbb/Battery_aging_09.pdf

...TMS is good, but gross cooling. Think nanoscale. The breakthrough in LI is nanoscale surface coatings that reduced resistance of the phosphates. Look at the scale of the heating micrographs. The heating increases the rate of deposition/plating..

 

Thanks for the link.

According to slide 10, a battery kept a 55 degrees C and operated at very high charge/discharge rates will start to lose capacity after 30,000 cycles of operation. At two cycles per day, that's about 40 years.

So is this team wrong or is the risk of fast charging a red herring?

 

They are using 16C on a single cell in an accelerated testing. We are not given the cycle depth, just the current flow rate.
16C means a rate which would fully discharge the cell in 1/16 of an hour. Usually the cycle is very shallow a matter of seconds or less.

The point they are conveying is the nano mechanism which increased internal/surface resistance.

 

NO....Again, OSU is runnning an accelerated test bed. Their cycle is very, very shallow and very,very brief. Like shifting a fraction of a wh in and out very quickly. Remember C is a rate ...current over time normalized for capacity.

However, Some battery manufacturers and labs spec 1C as a max charge rate for similiar batteries. 10kw is what I understood from hearsay from previous posts in this thread is what is being proposed. or 0.63. That's in the range of ICE charging.

If you are going to pursue this with the supplier, it should be interesting.

I am not recommending any mods let alone high rate DC charging or suggesting that you do it.
I do not think it's safe as a shade tree venture.

enjoyed chatting, thanks.