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A battery is a battery, any lithium battery from a drill to a tesla is simply a 1.5 volt cylindrical cell stacked in series to produce the desired Voltage, then

A battery is a battery, any lithium battery from a drill to a tesla is simply a 1.5 volt cylindrical cell stacked in series to produce the desired Voltage, then these stacks are connected in parallel or series again as needed (depends on application) to increase the load it can handle (Amperage). The safety features you're so worried about are just fuses. And maybe some diodes if you're that worried. I can say that installing a bank on a piece of plywood on your garage wall is obviously stupid, but a simple opening of the NEC book will show the code for a battery bank, shall have clearance from a wall and rest on non-flammable/non-conductive material, usually in a nuclear power plant or a substation we would build a rack out of metal then install ABS plastic shields. Source: I'm an industrial electrician and went through an IBEW apprenticeship,

mrtimo 9y ago
Honest question, I thought they were 3.6 volt cells?
- zootboy 9y ago
  Depends on the chemistry. Normal li-ion chemistry is nominal 3.7V, max 4.2V. LiFePO4 chemistry is nominal 3.3V, max 3.6V. Plus there are other variants that have different parameters. I'm not aware of any lithium-based cell that has a nominal voltage of 1.5V, the commenter was probably thinking of alkaline cells.
vvanders 9y ago
Nope, different lithium batteries have different chemistry compositions. A LiFePO4 will happily catch on fire if you charge it with the same voltage/current curve as a LiPo(3.6v vs 4.2v). [edit] To expand a bit, this[1] is a fantastic reference on exactly how complicated and involved the different chemistries can be. This is talking about Lead -> LiFePo4 but a lot of stuff applies to LiPo and other variants as well. [1] https://marinehowto.com/lifepo4-batteries-on-boats/ https://marinehowto.com/lifepo4-batteries-on-boats/
- snovv_crash 9y ago
  You have to try really hard to make LiFePO4 catch on fire. LiIon just requires 0.5v of overcharge, but LiFePO4 usually also needs a case puncture, followed by a short circuit.
- ScottBurson 9y ago
  From your linked article: > Please note that in all 68 of these RUINED LFP banks, that I have to date, there was not one incident of fire, explosion or dangerous off-gassing. So you can destroy them easily by overcharging or other mistake, but LiFePO4 is probably the safest of the lithium chemistries as far as fire goes.
  - vvanders 9y ago
    Fair enough, I'm used to pushing the packs a bit harder on discharge so I swapped that around(charge/discharge).
i_are_smart 9y ago
Sorry, but no. Most lithium chemistries have a nominal voltage near 3.3 - 3.7V per cell. When you stack lithium cells in series for any sort of high-performance application, you need additional balancing circuitry to bleed off energy from the cells individually (tiny variations between cells results in them having different capacities, which means some will charge up at different rates, resulting in them DISCHARGING at higher rates, which results in pretty serious negative effects for the life of the battery pack). The only exception here is extremely well matched cells, which is how Tesla is able to get away with not using much balancing circuitry (they are very picky about the cells they use, and have enough cells in stock to pick ones with very similar capacities). And the safety features include a lot more than fuses - there are over-voltage protection circuits (extremely important!), over-discharge protection circuits, temperature protection circuits (you can overheat a cell even without drawing too much power out of it). In short, large stacks of lithium cells are a difficult and dangerous beast to handle, and a lot of work goes into keeping them safe. These cells tend to have very low internal impedance, and as a result a chain of them can produce staggering amounts of power. Source: I work on the embedded protection systems for a company which makes specialty lithium-ion battery systems for industrial, aerospace, and defense customers.
- crankylinuxuser 9y ago
  Not to mention" that LiIon cells were known by Ford and Edison. Their first examples are in the museum in Florida. Why didn't they use them in the first cars? When they either over or undervolted, they tended to explode. We didn't have the electrical circuitry to handle lithiums. Now we do, mostly. Bad "spray fire and death" style accidents still happen.
snovv_crash 9y ago
> any lithium battery from a drill to a tesla is simply a 1.5 volt cylindrical cell Incorrect. Lithium Ion batteries are 3.7V (nominal) with different chemistries varying from 3.2V (LiFePO4) to 3.8V (LiHV). >The safety features you're so worried about are just fuses. And maybe some diodes if you're that worried. Also incorrect. It won't just have fuses, but also low voltage (over-discharge) protection, high voltage (over-charge) protection, and transient current limiting with auto reset, typically done with an IC + FETs per small pack of cells or even per cell. So before you can build your pack you need to make sure that the cells all have the same chemistry and charge level, and that the ICs are programmed to cut out at the same voltage and current, otherwise you get nasty surprises when connecting in parallel (the voltage mismatch) or in series (current mismatch) or any hybrid of the two. Source: specced and sourced cells, safety ICs and chargers for portable payment terminals. And 15 years experience in electric RC aircraft.
- amphibian87 9y ago
  nice, I cede all your points. Glad to learn from everyone and help my ignorance in the matter. Thanks all.
lightedman 9y ago
"Source: I'm an industrial electrician and went through an IBEW apprenticeship," "any lithium battery from a drill to a tesla is simply a 1.5 volt" I wouldn't hire you to wire my buildings when you don't even know the nominal voltages for lithium chemistries.

mrtimo 9y ago

Honest question, I thought they were 3.6 volt cells?

zootboy 9y ago
Depends on the chemistry. Normal li-ion chemistry is nominal 3.7V, max 4.2V. LiFePO4 chemistry is nominal 3.3V, max 3.6V. Plus there are other variants that have different parameters. I'm not aware of any lithium-based cell that has a nominal voltage of 1.5V, the commenter was probably thinking of alkaline cells.

vvanders 9y ago

Nope, different lithium batteries have different chemistry compositions. A LiFePO4 will happily catch on fire if you charge it with the same voltage/current curve as a LiPo(3.6v vs 4.2v). [edit] To expand a bit, this[1] is a fantastic reference on exactly how complicated and involved the different chemistries can be. This is talking about Lead -> LiFePo4 but a lot of stuff applies to LiPo and other variants as well. [1] https://marinehowto.com/lifepo4-batteries-on-boats/ https://marinehowto.com/lifepo4-batteries-on-boats/

snovv_crash 9y ago
You have to try really hard to make LiFePO4 catch on fire. LiIon just requires 0.5v of overcharge, but LiFePO4 usually also needs a case puncture, followed by a short circuit.
ScottBurson 9y ago
From your linked article: > Please note that in all 68 of these RUINED LFP banks, that I have to date, there was not one incident of fire, explosion or dangerous off-gassing. So you can destroy them easily by overcharging or other mistake, but LiFePO4 is probably the safest of the lithium chemistries as far as fire goes.
- vvanders 9y ago
  Fair enough, I'm used to pushing the packs a bit harder on discharge so I swapped that around(charge/discharge).

i_are_smart 9y ago

Sorry, but no. Most lithium chemistries have a nominal voltage near 3.3 - 3.7V per cell. When you stack lithium cells in series for any sort of high-performance application, you need additional balancing circuitry to bleed off energy from the cells individually (tiny variations between cells results in them having different capacities, which means some will charge up at different rates, resulting in them DISCHARGING at higher rates, which results in pretty serious negative effects for the life of the battery pack). The only exception here is extremely well matched cells, which is how Tesla is able to get away with not using much balancing circuitry (they are very picky about the cells they use, and have enough cells in stock to pick ones with very similar capacities). And the safety features include a lot more than fuses - there are over-voltage protection circuits (extremely important!), over-discharge protection circuits, temperature protection circuits (you can overheat a cell even without drawing too much power out of it). In short, large stacks of lithium cells are a difficult and dangerous beast to handle, and a lot of work goes into keeping them safe. These cells tend to have very low internal impedance, and as a result a chain of them can produce staggering amounts of power. Source: I work on the embedded protection systems for a company which makes specialty lithium-ion battery systems for industrial, aerospace, and defense customers.

crankylinuxuser 9y ago
Not to mention" that LiIon cells were known by Ford and Edison. Their first examples are in the museum in Florida. Why didn't they use them in the first cars? When they either over or undervolted, they tended to explode. We didn't have the electrical circuitry to handle lithiums. Now we do, mostly. Bad "spray fire and death" style accidents still happen.

snovv_crash 9y ago

> any lithium battery from a drill to a tesla is simply a 1.5 volt cylindrical cell Incorrect. Lithium Ion batteries are 3.7V (nominal) with different chemistries varying from 3.2V (LiFePO4) to 3.8V (LiHV). >The safety features you're so worried about are just fuses. And maybe some diodes if you're that worried. Also incorrect. It won't just have fuses, but also low voltage (over-discharge) protection, high voltage (over-charge) protection, and transient current limiting with auto reset, typically done with an IC + FETs per small pack of cells or even per cell. So before you can build your pack you need to make sure that the cells all have the same chemistry and charge level, and that the ICs are programmed to cut out at the same voltage and current, otherwise you get nasty surprises when connecting in parallel (the voltage mismatch) or in series (current mismatch) or any hybrid of the two. Source: specced and sourced cells, safety ICs and chargers for portable payment terminals. And 15 years experience in electric RC aircraft.

amphibian87 9y ago
nice, I cede all your points. Glad to learn from everyone and help my ignorance in the matter. Thanks all.

lightedman 9y ago

"Source: I'm an industrial electrician and went through an IBEW apprenticeship," "any lithium battery from a drill to a tesla is simply a 1.5 volt" I wouldn't hire you to wire my buildings when you don't even know the nominal voltages for lithium chemistries.