LiFePo4 tech?

[Chazmo]

So… When I asked about solid state a while back I got crickets. I wonder if anyone will chime in here regarding LiFePo4:

I’ve been reading up on lithium iron phosphate (LiFePo4). This technology seems far less prone to fire danger than current lithium ion batteries.

I know a guy who built a house battery originally from lead-acid, but now with LiFePo4 car battery sized batteries. If LiFePo4 is (way) safer than LiPo, why aren’t we seeing these in bike batteries? Is anyone building micro mobility products around this energy storage tech?

The “knock” I’ve seen regarding this technology is less energy density and less discharge rate. What I don’t know is whether this is unusable or shall I say less useful than LiPo...

 

[Stefan Mikes]

The batteries in e-bikes are Li-Ion not LiPo.

 

[Gionnirocket]

The chemistry being used right now... is at the moment, the one best suited to the task.

 

[Chazmo]

The batteries in e-bikes are Li-Ion not LiPo.

That’s true, but they are very similar, Stefan. Both technologies burn extremely hot and cascade among cells… And, on that note,

The chemistry being used right now... is at the moment, the one best suited to the task.

I think the fire risk needs to be factored into the “suited to” argument, Gionni… I mean what you’re saying is correct, but lithium-ion cell flammability needs to be part of the equation… Stated slightly differently, being “suited to” the micro-mobility application has to include the fire danger/risk. I mean, well, gasoline is dangerous… sure… But lithium-ion fires are “a whole ‘nuther” world of hurt.

There’s a strong argument in favor of lithium-ion in that cheap omnipresence of the technology makes it irresistible in our space. And, of course, without lithium ion we wouldn’t have had a personal device revolution either. But, when we pack these cells into dense matrices to make the powerful batteries we need, there is a lot of risk.

 

[Gionnirocket]

That’s true, but they are very similar, Stefan. Both technologies burn extremely hot and cascade among cells… And, on that note,


I think the fire risk needs to be factored into the “suited to” argument, Gionni… I mean what you’re saying is correct, but lithium-ion cell flammability needs to be part of the equation… Stated slightly differently, being “suited to” the micro-mobility application has to include the fire danger/risk. I mean, well, gasoline is dangerous… sure… But lithium-ion fires are “a whole ‘nuther” world of hurt.

There’s a strong argument in favor of lithium-ion in that cheap omnipresence of the technology makes it irresistible in our space. And, of course, without lithium ion we wouldn’t have had a personal device revolution either. But, when we pack these cells into dense matrices to make the powerful batteries we need, there is a lot of risk.

Sure quality needs to be regulated and safer practices adopted.
But what percentage of the fires are caused by end user ignorance?
Statistically space heaters and smoking cause many more fires.

 

[Chazmo]

Sure quality needs to be regulated and safer practices adopted.
But what percentage of the fires are caused by end user ignorance?
Statistically space heaters and smoking cause many more fires.

Good points. I don’t know the stats, but we certainly hear a lot about these fires, and I find it troubling.

There was a thread here recently about someone wanting to ride their bike across the US, and a bunch of people were indicating their own concern about charging their batteries in hotels, etc. I guess I’m saying that I would like to take that off the table (some day).

I’m seeing barely any progress with solid state batteries, which (at least initially) seem like the holy grail. Energy storage is key to our future, and I want to see things moving forward and to understand the options.

 

[Gionnirocket]

A Li-ion has 2 to 3 times the energy capacity when measured by size and weight.
Things are getting safer but for now I wouldn't want my bike heavier or with less ability.

 

[indianajo]

Not wanting a huge fire between my legs, I bought 2 LIFePo4 batteries in 2017. Both were garbage. One dropped from 54 to 7.5 volts with loads over 75 watts, the other to 11.5 volts. The vendors are long moribund, but one was via Amazon and one was via E-bay. I bought a LiIon battery 1/2018, I'm still using it. I have it mounted over top the front wheel, where likelihood of car crash is low, and any fire would be 1' away from my body. See the white plastic wrapped device over the front wheel in my avatar. Having read the news stories, I charge outside: Never in freezing weather.
With the weight paranoia of the biking customer base, no major manufacturer is going to build a model with a battery 40% heavier than a LIIon. I came to the conclusion that there were no reliable vendors of LIFePO4 batteries in the 36-48 v 10-25 AH range fall 2017. Also if you think a motel is going to allow you to take a bicycle in your room because it is slightly different than the firebombs, you over-estimate the education of motel clerks or of insurance companies. Bicycles will be painted black with a broad brush. Safety labels can easily be counterfeited, also.