Hi exp30002(?)
I often use wikipedia for a quick reference, but there is a reason that universities will not allow wikipedia as a citation in any college paper. The information that you quoted is probaly true for some lithium powered devices, like laptops, cell phones or cordless drills, but is mostly incorrect for the the prismatic cells that are often used in EVs and electric boats like mine.
The LiFePO4 cells will not combust if overcharged. Deep discharge can short circuit the cell. Loose Li cells do not have any additional circuitry, they are just batteries like nicads or flooded lead-acid batteries. The safe voltage range differs by manufacturer, for example CALB prismatic cells have a narrower range than Thundersky prismatic cells. Without adding any BMS equipment, the cells have no added parasitical drain, though they will go dead eventually like every battery, lithium cells are slower than most other types (<2%/month). This means that a Li battery pack will probably be flat after years of unattended storage. Minimum charging temperatures also vary, but 0c deg for charging and -20c for discharge and storage are fairly common.
The real message here is to look at the manufacturer's specs for any battery, Lithium or other, that one is considering to confirm that it meets your operational conditions and normal usage.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, exp30002 <exp30002@...> wrote:
>
> The mathematics, and reasoning seems right. Else, I do not think the
> lithium
> batteries can be fully discharged. I think there is a small circuitry in
> each lithium
> cell to prevent recharge after a total discharge.
>
> This is what I found:
>
> http://en.wikipedia.org/wiki/Lithium-ion_battery
>
> Safety requirements
>
> If overheated or overcharged, Li-ion batteries may suffer thermal runaway
> and cell rupture.[56] In extreme cases this can lead to combustion. Deep
> discharge may short-circuit the cell, in which case recharging would be
> unsafe.[57] To reduce these risks, Lithium-ion battery packs contain
> fail-safe circuitry that shuts down the battery when its voltage is outside
> the safe range of 3–4.2 V per cell.[35][47] When stored for long periods
> the small current draw of the protection circuitry itself may drain the
> battery below its shut down voltage; normal chargers are then ineffective.
> Many types of lithium-ion cell cannot be charged safely below 0°C.[58]
>
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