Why LiFePo is basically invisible? - Page 1
Forum section: electronics / beginners

author: abit
author_rank: Contributor
timestamp: May 02, 2015, 09:01:54 am
content: It appears to be a sound technology, but application and IC support of it - to me - appears to be scarce. Am I seeing this right?Update: Thanks, I know that market acceptance is THE principal force, and thank you to share what you know and/or think! i read the entire thread.eas:Thanks for some ‘reality check’ - I am STILL shopping for a household UPS with LiFePo, you just made your point very clear on that! It is NOT that LiFePo is not a possible alternative, it is in the fact that LiFePo is NOT in the game and have NO chances to prove itself, and has not had the time and resources to develop itself to the point where Li-Ion is today. Very little of Earth's population live under extreme temps, so go figure how is that a valid argument.Frankly… Today if i had the chance to choose between a 3x3mm Li-Ion and LiFePo cell at whatever voltage between 3-4VDC - I would choose LiFePo. At those dimensions to start with, what engineer would spring for a better ‘return’ vs better ‘chemistry’ to manage?

author: abit
author_rank: Contributor
timestamp: May 02, 2015, 09:18:35 am
content: So, it is secondary to some superiors. SLA is so and NiMH is so and NiCad is so - but LiFePo is space-age to all the other alternatives. Still, basically invisible and practically un-supported. Why?

author: Psi
author_rank: Super Contributor
timestamp: May 02, 2015, 10:07:28 am
content: Because capacity is king.

author: lutkeveld
author_rank: Regular Contributor
timestamp: May 02, 2015, 11:00:40 am
content: Market acceptance. It will come I think.It's just that for high-density people choose li-ion and for low-density leadacid.LiFe is an inbetween option, but has several attractive features that many people don't know of.I can see every lead acid car battery being replaced by LiFe.

author: mzzj
author_rank: Super Contributor
timestamp: May 02, 2015, 11:16:04 am
content: Quote from: lutkeveld on May 02, 2015, 11:00:40 amHow is LiFe charging at -30 celsius temperature?

author: mikerj
author_rank: Super Contributor
timestamp: May 02, 2015, 11:30:51 am
content: Quote from: abit on May 02, 2015, 09:18:35 amNiMh has higher volumetric energy density, similar gravimetric energy density, is a well proven and safe chemistry and is significantly cheaper.LiFePO4 certainly has some advantages (e.g. cycle life) but unless an application specifically requires those advantages the cost difference would likely rule them out at the moment.

author: lutkeveld
author_rank: Regular Contributor
timestamp: May 02, 2015, 12:29:01 pm
content: Quote from: mzzj on May 02, 2015, 11:16:04 amMuch better than leadacid at that temperature. Because of the better performance in a broader temp range, starting your car in the winter won't be any problem

author: mikerj
author_rank: Super Contributor
timestamp: May 02, 2015, 12:57:14 pm
content: Quote from: lutkeveld on May 02, 2015, 12:29:01 pmLifePo4 cells tend to have quite poor charge/discharge characteristics at low temperatures, worse than lead acid in many cases. You can already buy LifePo4 batteries as lightweight alternatives for motorcycles (and probably competition cars), which have high CCA ratings for their size, but much lower capacity. These often won't even turn the engine over under very cold conditions first time, but attempting to start the engine draws enough current to warm the cells so a second or third attempt usually works.

author: lutkeveld
author_rank: Regular Contributor
timestamp: May 02, 2015, 02:16:40 pm
content: From what I've read, LiFePO4 seems to handle low/high temperatures much better. -20 degrees Celcius should be no problem.

author: eas
author_rank: Frequent Contributor
timestamp: May 03, 2015, 02:06:38 am
content: Why is LiFePO4 basically invisible? Because it hasn't lived up to the early hype.The same was true of some of the earlier lithium ion battery chemistries, but they had the advantage of coming first, and most of their growing pains are behind them. As a result, ongoing R&D is amortized across the huge market for traditional cells, and has been bringing steady progress.Some things to think about:* As recently as 2013, commercial LiFePO4 cells had serious capacity fade when charged at elevated, but not unusual, temperatures.* If you treat other LiIon cells as if they have the energy density of LiFePO4 cells by limiting their operating voltage range, you can get real lifespans that are similar to the promised lifespans of LiFePO4.* The power delivery capabilities of LiFePO4 aren't really important for most consumer electronics, and for many applications where it may be more important like power tools and electric vehicles, runtime is also an issue, and so energy density is an issue. Once you get enough cells for desirable runtimes, per-cell power delivery is less of an issue.We'll see what the future holds. I'd say though, that the expectations people have of traditional lithium ion batteries wearing out after a few years is probably more about the average lifetimes of the consumer electronics that most of them went in to. There is going to be huge growth in the coming years in electric vehicles and fixed power storage, both of which have longer lifetimes. Batteries for consumer electronics could be less than half the market in less than 5 years. I expect battery lifetimes will improve rapidly. In fact, they probably already have.

author: mikerj
author_rank: Super Contributor
timestamp: May 03, 2015, 09:59:33 am
content: Quote from: lutkeveld on May 02, 2015, 02:16:40 pmHave a look atof starting a Harley from cold temperatures. This is very typical of LiFePo4 batteries that replace lead acid for starting applications.The output impedance of lead acid batteries also increases as they get colder, but they tend not to suffer as badly in this application. A LiFePo4 battery of equivalent capacity to the standard fit lead acid would probably be fine, but it would be significantly larger.