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Lithium Ion Battery Packs For Electric Vehicles

galvanggalvang Posts: 156
edited April 8 in General
With the advent of more electric cars coming into fruition in the future and the utilization of more lithium ion batteries, have the auto manufacturers done their homework?? I wonder.

Why I ask? Lithium Ion batts have some technical issues and safety concerns. First of all, lithium ions have limitations on how much the batteries can be charged and discharged. Usually it's about 500 cycles. If you charge your vehicle once a day then thats 500days of battery life. Are automobile lithium Ions more robust?? I liked to know, and what is the cycle life of those batteries? Anyone know??

Then there is safety concerns. The battery packs will have to be well protected against electrical overcharging and physical abuse such as in a crash. Depending on the chemistry of the lithium ion batt overcharging may overheat the battery cells and may cause and explosion or severe outgassing. Shorts can cause this too. I believe they can resolve those issues though they need to be thought out thoroughly.

With Tesla on the road already, I certainly hope they did right.

Comments from anyone.
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Comments

  • PFFlyer@EdmundsPFFlyer@Edmunds Pennsylvania Furnace, PAPosts: 5,807
    More electric vehicle news on the Alternate Route

    Perfect Storm?

    PFFlyer@Edmunds

    Moderator - Hatchbacks & Hybrid Vehicles

  • PFFlyer@EdmundsPFFlyer@Edmunds Pennsylvania Furnace, PAPosts: 5,807
    A very interesting bit of electric vehicle news came up on the Alternate Route this morning...

    Bond, James Bond

    PFFlyer@Edmunds

    Moderator - Hatchbacks & Hybrid Vehicles

  • PFFlyer@EdmundsPFFlyer@Edmunds Pennsylvania Furnace, PAPosts: 5,807
    Still working out kinks in the Volt like powering the windshield wipers. Talk about biting off more than you can chew. But it makes for a day's blog entry ;)

    Beat To The Punch?

    PFFlyer@Edmunds

    Moderator - Hatchbacks & Hybrid Vehicles

  • tpetpe Posts: 2,342
    First of all, lithium ions have limitations on how much the batteries can be charged and discharged. Usually it's about 500 cycles. If you charge your vehicle once a day then thats 500days of battery life.

    A cycle represents a full charge after a full discharge. If you only discharge the batteries 50% every day then 500 days of recharging would be 250 cycles.

    We've all heard of the much publicized limitations regarding Li-ion batteries. I've got to believe that the engineers at Mercedes, Honda, GM, et al, have at least as much insight into these matters as the typical poster on Edmunds. Honda will be using Li-ion batteries in its FCX. GM will be using it in the fuel cell Equinox. Mercedes will be fielding it in their S class hybrid next year. I'm not a chemical or material engineer but common sense tells me that these multi-billion dollar companies would not be putting these battery packs in their vehicles if they didn't have a high level of confidence.
  • galvanggalvang Posts: 156
    TPE, I went through a recent presentation on a new type of high power lithium-ion batteries with nano-phosphate chemistry. This company claims up to a 1000 cycles of 100% depth of discharge. Meaning a battery full charged then fully discharged 1000 times. Also they claim to be safer than standard lithium ion batteries. I believe these batteries will be used by GM on the volt and upcoming Hybrids. They also calm 50% improvement in mileage with the use of these type of batteries over todays hybrids.

    Lithium Ion have been around for awhile but for this new type of battery both the auto MFGr and the battery MFGr would have to prove that they are reliable and safe. They look great on paper but the proof is in the real world application in this case autos.
  • gagricegagrice San DiegoPosts: 28,681
    This company claims up to a 1000 cycles of 100% depth of discharge.

    UP TO 1000 cycles. That is best case it sounds like to me. How will they give a 10 year warranty on a battery like that? It is not likely you will totally discharge the battery very often. At least hopefully not as you would be dead in the water. Toyota has overcome some of the problems with deep discharging by only charging to 80% and not allowing the battery to go below 20%. In an EV that would cut your range by 40%.
  • tpetpe Posts: 2,342
    This company claims up to a 1000 cycles of 100% depth of discharge

    I think you might have left out a zero and meant 10,000 cycles. I've seen that claim also from Altair Nanotechnologies. 1000 cycles would not represent an improvement over what NiMH batteries are capable of. Also it probably wouldn't be adequate for an EV unless the cost was comparable to lead acid. I believe that GM has set a target of 3,000 cycles out of whoever they choose to supply their battery packs.

    The problem with Altairnano's batteries is that their energy density isn't really any better than NiMH. Meaning that for a given range the battery pack is not going to weigh any less. However Altairnano's batteries have a much greater power density, which will allow them to be recharged/discharged much faster. My personal opinion is that Altairnano's batteries are perfect for a PHEV application where you are only going for around 40 miles of all electric range. I think that for a pure EV with much over 100 mile range they would end up being too heavy. For instance if you were to use Altairnano's batteries in the Tesla Roadster you would add about 800 lbs to a battery pack that already weighs ~900 lbs.
  • galvanggalvang Posts: 156
    These aren't from Altair rather these are from A123 Technologies. The cycle life is dependent on how deep is the discharge. For 100% it's 1000 cycles but for 85% depth then it's about 4K cycles as you stated, which is phenomenal. Usually the failure mode isn't catastrophic rather when the batts fail ussally the failure is attributed to the voltage output doesn't meet to spec. Here's the link.

    http://www.a123systems.com/#/applications/phev/pchart2/

    As for the energy density of the A123 Nano-phosphates, there are just as good or even better than standard Lithium ions. They operate at much higher voltage than NiMH almost 3 times as much with the same capacity. Plus these batteries can be fast charged in a matter of minutes. With the higher energy density and the ability to pull high short term electrical loads like with hybrid, it's perfect for a PHEV or a pure EV. In fact GM has is working with them to develop the batts for their EV the Volt. I like these new batt technology.

    http://www.a123systems.com/#/applications/phev/
  • galvanggalvang Posts: 156
    Toyota has overcome some of the problems with deep discharging by only charging to 80% and not allowing the battery to go below 20%. In an EV that would cut your range by 40%

    You are right if the discharge is 100% then the range is increased but at the same time reducing the battery's cycle life. And vice versa the opposite occurs. It's a trade off.

    The physics is there, now if the auto MFGrs can apply this very same technology to large SUVs and increase the mileage significantly, that would be a feat. More than likely it would initially be expensive but as time goes on I'm sure it will be competitive with a gas engine.
  • tpetpe Posts: 2,342
    I'm familiar with A123 Systems. GM is currently putting their battery packs through rigorous/accelerated testing meant to simulate years of use. My understanding is that so far these batteries have met all the marks. GM has stated that they will have a fully functioning Volt prototype by late Spring.
  • galvanggalvang Posts: 156
    rigorous/accelerated testing meant

    Yes, I familiar with the test scheme. Probably accelerated voltage, high and cold ambient temperatures, multi-cycle 100% depth charges and discharges. I hope all goes well.

    Now the next item for them to complete is when these batteries go into high volume production they need insure consistant good quality. Motorola's six sigma quality process maybe a good quality model. Good luck GM.
  • galvanggalvang Posts: 156
    HERE'S AN ENCOURAGING ARTICLE FROM GM.

    GM tests Volt batteries

    General Motors' engineers say they have developed a new computer algorithm to accelerate durability testing of the lithium-ion batteries needed for its plug-in electric Volt to be produced

    GM says the new algorithm compresses the equivalent of 10 years of battery use into the tight timeframe required to get the Volt into production by late 2010.

    Battery testing and load cycling runs around the clock in the company's test labs in Michigan and Germany.

    "The challenge is predicting 10 years of battery life with just over two years of testing time," said Frank Weber, global vehicle chief engineer of the Chevrolet Volt and E-Flex systems.

    Actual test vehicles will have to be used to account for the many in-use variables that cannot be accounted for in lab testing.

    The Volt's T-shaped battery pack will fit into the centre tunnel and under the rear seats, and will become an integral part of the vehicle's structure.
  • gagricegagrice San DiegoPosts: 28,681
    It will be interesting to see how they test for Longevity, the real killer of Li-Ion batteries.

    I just pulled one of my laptops out for a trip and the Li-Ion battery I replaced a year ago is completely dead. Cannot charge it at all. I would not touch a car with Li-Ion batteries till I see them in full use for 10 years with NO problems. Right now I hate the technology and wish I could get a NiMH replacement for this Inspiron 4100. The last one just a year ago was $169.99 now that same piece of crap Sony Li-Ion battery is $249.99. So I have a laptop that can only be used where I have AC power. You don't have that luxury with an Electric car.

    PS
    My old Inspiron 7000 with a NiMH battery is still working after 7 years. Could be the reason Toyota is steering clear of Li-Ion.

    The Tesla has 6800 of the same piece of crap cells that are in my defunct Dell Laptop. I hope they get videos of George Clooney stuck by the road with his broke down Tesla after a couple months of use.
  • galvanggalvang Posts: 156
    I would not touch a car with Li-Ion batteries till I see them in full use for 10 years with NO problems.

    These batteries that are being used in the Volt are different type and chemistry than the ones used in your laptop. These are Nano-phosphate lithium ions that are industrial strength. They are far superior than the ones used in current commercial applications such as your phones and laptops. If the testing goes well, I just might get one of these wheels.

    Actually Toyota is going with Lithium Ions starting 2010 for their Prius.

    The Tesla has 6800 of the same piece of crap cells that are in my defunct Dell Laptop. I hope they get videos of George Clooney stuck by the road with his broke down Tesla after a couple months of use.

    LOL, I like George he's a good spokes person but you need someone who understands the technology before he can back it up. Yea, I hope he has triple AAA.
  • tpetpe Posts: 2,342
    You're correct in pointing out that the Li-ion chemistry being considered for PHEVs is fundamentally different than what's found in a laptop. Even still GM fully expects these battery packs to degrade over time. That is one of the reasons why they will never be charged to over 80%. By the end of the battery pack's lifecycle that might represent as much charge as can be held but to the user it will be unnoticeable.

    And these battery packs will not be useless once they can no longer hold 80% of their original charge. Utility companies have already stated an interest in buying them to use for back-up power storage.
  • gagricegagrice San DiegoPosts: 28,681
    I am not an engineer or scientist. I would think that some of the elements could be recycled into new Li-Ion batteries. I am sure in my case that one cell in the battery of my laptop is defective. The warranty is So short that the MFG is safe with a year. That should not be the case with cars like the Volt. It should be at least 10 years as the Hybrids.

    If they are only planning to charge to 80% that will require a 20% bigger battery to get the desired mileage, right?
  • tpetpe Posts: 2,342
    If they are only planning to charge to 80% that will require a 20% bigger battery to get the desired mileage, right?

    The Volt will come with a 16 kWh battery pack. This would be enough to go approximately 80 miles if you went from 100% state of charge (SOC) to full depletion. This car will only use 50% of that at first. Going from 80% SOC to 30% before the ICE generator kicks in to start recharging. As the battery starts losing it's ability to hold a full charge that will come off the top, the 80-100% that wasn't previously being used. So you will still have the 40 miles of all electric range that you had when the battery pack was new. This scheme defininitely requires a bigger battery pack than would be needed if you could always charge to 100% and not have to concern yourself with battery degradation.

    I personally don't care about the battery lasting 10 years as long as the replacement is affordable. My tires only last about 4 years and cost around $1,000 to replace. A battery pack should be viewed in the same way, as something that wears out. If a battery pack lasted 5 years and cost $2,000 to replace I could live with that since I'll be saving more than that in gas. Unfortunately at the present time the cost to replace a battery pack of this size would be quite a bit more than $2,000. IMO, that represents the biggest obstacle to EVs, getting the battery price down.

    Actually I'd rather have a cheaper battery pack that lasted 5 years as opposed to a more expensive one that lasted 10 years. For one thing I have never kept a car for 10 years. More importantly battery technology continues to evolve and in all likelihood there will be something considerably better well before this 10 years is up that I would want to upgrade to anyway.
  • gagricegagrice San DiegoPosts: 28,681
    If a battery pack lasted 5 years and cost $2,000

    I think you better add another "0" to that number. You cannot get the little NiMH OEM battery for the Prius that cheap. I know the battery in my laptop went up 32% over the last year. The Plugin option for the Prius is $12,000 to go 10 miles with Li-Ion. I would bet that over half that $48k GM is talking about for cost is the battery pack.
  • tpetpe Posts: 2,342
    I think you better add another "0" to that number.

    I don't think so. Everything that I've read indicates the cost will be between $6,000 and $8,000 for the battery pack. When GM solicited proposals from potential battery supplies this was one of their criteria.

    volt battery pack
  • galvanggalvang Posts: 156
    I don't think so. Everything that I've read indicates the cost will be between $6,000 and $8,000 for the battery pack. When GM solicited proposals from potential battery supplies this was one of their criteria.

    That makes more sense. Considering that gm wants a half decent market share with the volt. Your article was excellent. GM is considering leasing the Volt's battery. Why not just lease the entire vehicle and the battery together as you do with other vehicles. Sounds like another scheme to collect additional funds for the volts fuel savings.
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