Lithium Ion battery safety concerns

I think that the car is doing a good job of managing the charge level Even when the battery is already full and you are producing energy from regenerative braking going down a hill, i think it will start the engine and use engine braking instead or something like that. However, if the car is towed, the front wheels must not touch the ground because it could cause overcharging and start a fire.

 

The PiP has built up a lot more in-service time than the 787, and we haven't yet heard of any similar problems, so I don't think we have much to worry about at this time.

Besides, should you smell smoke, you can pull over and evacuate the car very quickly. Its not like you are out over the Pacific several hours from the nearest possible pullover.

Even the burning Volt batteries (before improvements) weren't a meaningful risk to the occupants, as the quickest one didn't ignite until a week after serious crash damage. Very few people stay inside a crashed car that long.

 

The batteries are not the same
Also the pip has no liquid coolant that could potentially ignite
Just drive and don't worry about it

 

+1

The 787's use Lithium Cobalt... Which is just plain stupid. This was what was used in Sony and Dell (and other) laptop batteries a few years ago when they were all catching fire. Overcharing LiCo batteries produces an extremely exothermic reaction.

 

Toyota engineers are very cautious and safety oriented. Remember they just had the gas pedal problem several years ago. They are safety paranoid so you can bet they have super safety margins with the batteries. They have been using battery technology since 2000. The Li-ion is new but they tested it extensively with a fleet of pre-production cars. In addition, as has been said, thousands have been on the road since march with no known issues. While the new Boing planes are less than 20 and they started having issues immediately. Nothing similar at all. Enjoy with confidence.

 

A full charge for PiP is 85%. At that level, even the regen brake is limited to charge at a third of the maximum rate.

PiP battery is air cooled by two fans (active). The air is drawn from the cabin (air conditioned). It does not use liquid cooling that can short out electronics if it is leaked.

 

Not to mention that the suspected issue with the 787 batteries is the change in temperature and pressure. Unless you are flying your pip at 30,000 ft (unlikely) you probably have nothing to worry about.

Material have 3 different states: vapor, liquid, solid. Generally the properties are knows (water boils at 212f, freezes at 32f ect) but that is only true at the pressure we have at sea level. If you change the pressure the material property changes as well.

Boiling Points of Water at Various Elevations

Your batteries are fine, dont freak or overthink it. Otherwise maybe your camera, laptop, and cell phone are going to explode too!!!

 

You do realize there is a 10.6 gallon tank of flammable explosive liquid underneath the batteries right? You should worry about that catching fire before the batteries. Gasoline is contained inside a container with thin metal walls, thin compared to the casing of the battery. I'm not saying there is no danger of fire or explosion with batteries but if you're going to worry about something, I'd choose the more likely scenario that your car goes up in an inferno due to a gas leak. Don't forget the Ford Pinto.

 

Yikes. I hadn't seen any reports of the particular chemistry used, until now. With a spectrum of lithium choices available, from LiCo on the most risky side to LiFePO at the safest end and several more choices and mixtures in between, it does seem unusual that they selected the one with the greatest risk. But I'll have to wait for the engineering reports before passing any more judgement.

 

Thanks to someone on MyNissanLeaf:
Aviation | GSYuasa Lithium Power which points to a data sheet at http://www.s399157097.onlinehome.us/SpecSheets/LVP10-65.pdf.

 

actually, cell phone and laptop batteries HAVE exploded in the past, and as mentioned by someone else earlier in the thread, used the same chemistry as these 787 batteries did.

 

I am aware, however, I am willing to bet you have at least 1 cell phone, laptop and camera. so I stand by my post

 

This is what i say when someone tell me that hybrid and ev car are dangerous because of the high voltage battery. I think that if we were all driving on electricity and someone would put a gas tank in his car, we would call this man a crazy!

 

Do we know which Li batt chemistry Toyota is using in PiP?

 

NMC (Sanyo) according to Dr.Anderman.

http://www.fkg.se/assets/Uploads/Andermanbatterytechnology.pdf

 

I'm a bit concerned about Li-ion batteries safety too. Lately one went faulty in my cell phone, the main syndrome being that it had lost some of its capacity, but also that it was becoming noticeably warm when charging. Of course I stopped using it immediately. Scaled up to car size (or plane as Boeing found out) "warm" translates as "searing hot", "pressure increase" might mean "explosion" and so on. In Boeing's case I don't think the issue is with the charger's circuitry design, after all almost any fool can design devices like that, but it's a case of a battery becoming faulty and starting to act up under normal charging voltage and current conditions. So, all in all, I'm a bit wary of the whole thing, what with the batteries being situated at the rear of the car and capable of catching fire with no-one noticing, and also being so close to the gas tank ? Personnaly I'd stick with the NiMh design where no such issues have ever been widely reported. Telling from my personal experience with a 2007 second-hand Prius, NiMh is no problems all round, and that's after having driven it 30,000 miles, having bought it with 50,000 on the clock. So, why change a winning team ?

 

^^^in simplistic terms, Boeing is using LiCo chemistry which is probably similar to what you have in your cell phone. The problem Boeing faces is the cells are larger and stacked too close togther so one bad cell can overheat the rest, and not adequately vented in case a problem. Most vehicles use different Li chemsitry less prone to overheat and/or smaller cells with better isolation from the rest of the cells.

At this point there are enough EV/PHEV Li batts in service (eg: 50000 Leafs alone) to suggest very good if not excellent safety record so far. My understanding is however all Li batts feature an organic (flammable) electrolyte solution inside which is something that needs to be managed properly in design. Obviously in the lack of a battery you are carrying a tank of flammable gasoline anyways.

 

You are making a false comparison because the lithium chemistries are completely different. Lithium mixed with Cobalt is extremely exothermic on the top end of the charge or when overstressed. The only advantage to using it is that the energy density is very high.

Your cell phone and most consumer grade electronics use Lithium Cobalt Oxide batteries, just like Boeing. Why? Because you want the longest run time out of your cell phone and most people treat them as disposable after 1-2 years. So lifelong longevity is not an issue.

Medical equipment, industrial equipment, power tools, and of course cars like the Prius use a very very different chemistry. Lithium mixed with Iron Phosphate is the most common (A123 cells in the Tesla for instance) and is commonly referred to by its chemical name, LiFePO4. Li = Lithium, Fe = Iron (think "Ferrous"), PO4 = Phosphate

Mixing Manganese and/or Nickel into the Lithium or LiCo gets you two other very widely used chemistries, Lithium Manganese Oxide and Lithium Nickel Manganese Cobalt Oxide.
These last 3 are inherently stable and very safe. This is what is used in electric vehicles. The downside is that the density is lower, so you need a larger battery pack to cover the same range. The upsides include longer life and the fact that overheating and stressing them is generally safe, but you may destroy the life of the cell. They kill themselves when abused, they don't take the whole ship down with them.

So there is nothing to fear about your PiP, or a Leaf, or a Tesla, or Volt or anything like that.