Experts say lithium-ion batteries must change to be safe

08.22.2007 :: 12:26PM EDT
  • highlandcynic

    The fundamental problem with lithium ion batteries is in the name. Lithium. Try taking some Lithium and exposing it to air and see what happens.

  • asdfasdfasd

    HC come on that is not the issue:

    The issue is dendrite formation overtime. As you recharge the battery the lithium ions are redeposited in a nonuniform manner and thus over time finger like formations start (dendrites). These form slower than the life of the batteries and are no danger UNLESS their is some metal flakes or other design issues that cause them to form faster.

    The problem with dendrites is that if they reach the other side of the battery they cause it to arch and explode.

    What the new technology for lithium batteries will be is lithium copolymer matrices that dont allow the dendrites to from and allow the battery to last longer and produce more energy. This technology far off and like all battery research needs more funding.

  • highlandcynic

    Excuse me? That is very much the issue. Lithium is a very volatile metal. The oxidization of which causes an exothermic reaction. How much more of an issue does it need to be? The problem with Lion batteries isn’t that they are toxic, it’s not that they just stop working it’s that they get hot and go bang…just like Lithium does when it oxidizes.

  • hodar

    Used to hear the same lamentation when a chip let loose and the power supply took out the entire motherboard.

    1. Demand unlimited peak demand for power – At some point in time, most motherboards will demand ~80% of full rated power, even if only for a couple milli-seconds. The power supply must never sag.

    2. Nominally, the motherboard only draws ~10-40% of rated power.

    3. When a chip lets loose (ie blows up) the impedance through the motherboard to the chip may be high enough that the power regulation circuitry thinks this is a ‘high demand’ situation, and lets the power continue to flow.

    4. Customer shows motherboard with nice crispy components, a molten pit that one may stick a finger through and is somewhat relieved that he still has a house to sleep in. That isn’t much consolation, though.

    5. With batteries, add the fact that no one has yet said “Oh, thank goodness my laptop only lasts 5 minutes on a full charge”. No, people want to plug their laptop into the adapter no more than maybe once a month. If I released a battery with a laptop operational storage capacity of 4 weeks, and this battery weighed 10 lbs – I’d retire and buy a Cruise Line to take me to my new home – the island of Jamaica.

    When a battery fails, usually it simply dies whimpering. Poor performance becomes bad performance until the thing is truly dead. The very low percentage that fail, fail dramatically because they have a lot of potential energy just begging to be set free.

    I sincerely doubt that “exothermic” (a non-threatening description and legal phrase that means ‘fire’ in layman terms) situation can ever be ruled out. Perhaps made a bit less frequent, but we are still talking about these events being in the thousandths of a percentage, if not millionths.

    More powerful batteries will mean bigger fires. Sure, we can possibly make the events leading to a fire less likely – but somehow, somewhere something will happen. And the bigger the battery capacity – the bigger and more dramatic the event will be.

  • highlandcynic

    Hodar (and ASDF)

    Seems like the principle problem you are both concerned about is the discharge rate that the battery is capable of. Much like the discussions of ultra capacitance, when you have a stupidly large amount of energy stored in a relatively small space and it gets out all at once, it’s not a good thing.

    Is the discharge rate from a Lithium Ion battery so high that simply cross connecting the electrodes can discharge the battery violently?

  • hodar


    This goes to how you define ‘violently’. One of the things I used to do as a kid (to my father’s displeasure) was to take the old lead-acid 9 Volt batteries used to power electric fences, and lay a small nail across the contacts. That nail would get hot, turn red, and the iron in the nail would eventually soften to the point that it would bend. That was HOT by any man’s definition, hot enough to start a fire. My father’s displeasure came from the fact that the battery was now dead, and at that time was very expensive to replace. This was well before Alkalines, and this style of battery was not re-chargeable. Think 1960-70’s technology.

    If you have a ‘high powered’ device, be it a laptop with a 3 GHz chip, a video card powering a 17 inch screen, a large HDD – you have significant power requirements. Ohm’s law and P=IV or P=I2R comes into play. Depending on the value of R, you will either develop a warm spot, a very hot spot, or discharge event limited only by the battery’s internal resistance.

    Generally speaking, a battery’s resistance is very low. This limits self-heating, efficiency, life cycles as well as the ability to deliver maximum current output to meet your processor’s peak demand needs.

    As you summarized, having an insane amount of potential energy stored in a small space – with a peak energy output that supports a boot process (initialize all memory, start HDD spins, light LCD screen, processor at full power, check all ports, ect.) and somehow require that the battery ‘magically’ limit it’s output to a point that will not cause damage is asking a bit much.

  • asdfasdfasd


    You live around hazardous chemicals all your life. To say that just because Lithium is a true metal and thus has those properties the issue is never the battery coming into contact with AIR, the issue is dendrite formation which causes the anode and cathode to touch arch and explode. This would happen in any ion exchange battery if dendrites where formed Lithium or no Lithium.

    Look do you think table salt is dangerous? By your logic you should, because in all cases where the sodium dissociates it has the potential to react with air. Ever pitched pure sodium into an air or water environment? Pretty fun, and that is why pure sodium in a lab environment is kept under an oil.

    Same goes in the lithium battery, no air no water, all is safe. But what happens as the dendrites form you get a potential for the two electrodes to touch and that is really bad.

    Again this is nothing to do with LITHIUM but the design of the battery, which is safe until you get flakes or other contaminants in the battery cell which speeds up the dendrite formation.

    You need to understand this fact HC or you should stop using most product you use because if put in the correct position most could hurt you.