Li-ion vs LiFePO4 Batteries: Advantages and Disadvantages

hey everyone micah here with ebikeschool.com and today we're going to talk about the difference between lithium iron phosphate cells and lithium ion cells when it comes to batteries now i just got in a bunch of new lithium iron phosphate battery cells here for a battery i'm going to be building soon so why don't we open these up check them out and then we're going to talk about why you might go with lithium iron phosphate or why lithium ion might be better for your needs now i got these cells from battery hookup it's a website that has all sorts of battery cells they have lithium iron phosphate and lithium ions you can get all sorts of interesting cells there plus a bunch of salvage cells modem batteries all sorts of things it's great for diy battery builders these are their in-house battery cells these are their 32650s and i've never used these cells before but i'm pretty excited about them basically each one of these is about 17 watt hours or so so there's a lot of capacity in each cell and i'm going to be able to build a pretty good sized battery i'm going to go with a 48 volt 20 amp hour battery so because these are five amp hours each it's going to only need four cells in parallel i was talking to tom when i got these batteries and he generously offered all of my viewers here on youtube a discount of five percent if you use the code ebike when you buy battery cells or any of the batteries that they offer so uh thanks a lot to tom for doing that and also that helps support my channel so they know that you guys found battery hookup through me and it helps me continue to make free videos like this all right so why am i going with lithium iron phosphate cells for my next battery now you've probably seen that i've done a lot of lithium ion battery building using 18650 cells and while there are lithium iron phosphate 18650 is available they're a lot more rare so to do a lithium iron phosphate battery for my next battery i'm going with these larger cells and lithium iron phosphate does have a number of advantages over lithium ion the first one that a lot of people think about is that the batteries just last longer these cells are probably going to last well over a thousand cycles many lithium iron phosphate lasts up to 2 000 cycles compare that to lithium ion you're talking about somewhere between 350 to 800 cycles depending on the chemistry so you get a lot longer life span here another advantage to lithium iron phosphate is that you can often get higher discharge these cells are rated for 3c so at a 5 amp hour cell you can get 15 amps out of each cell it varies depending on the type of lithium iron phosphate there are some cells that can go up higher you know like 20 25 c if you're familiar with a123 cells those were very popular a few years ago when it was harder to get a lot of different lithium iron phosphate cells those are really high power cells so the chemistry does allow higher power and if you really need high power then lithium iron phosphate might be a good way to go it also doesn't heat up as much when you do high power batteries so if you're going to pull a lot of current from batteries lithium iron phosphate might be another good option to cut down on that heat buildup that also leads us into one of the downsides of lithium iron phosphate though is that it's not as energy dense so while you can get more power out of it you need a physically larger battery because you just can't stuff as much capacity into as small a volume like you can with lithium-ion so you can see that these are pretty large cells right compared to 18650s now there is more capacity here but if you were to scale up an 18650 with lithium ion and it was the same size you'd actually get more capacity more watt hours so what that means is that in the end if you have a let's say a typical e-bike battery that's 48 volts and 15 amp hours it's just going to be a bigger battery if you use lithium iron phosphate it's going to be larger in volume it's going to be a bit heavier you're just talking about less energy density so that's why you usually see e-bike batteries built with lithium-ion because manufacturers want to have a smaller format battery another advantage of lithium ion over lithium iron phosphate is that it's cheaper up front so again that's why you often see it in e-bikes because the same battery with the same specs in terms of capacity voltage etc the same battery is going to be cheaper if you use lithium ion so we're often talking something like 20 25 percent not a huge difference you know it's not double the price but you do get a cheaper upfront cost of lithium ion the downside is that because lithium ion doesn't last as long the overall cost for the lifetime of the battery is still going to be better with lithium iron phosphate because while it might cost i don't know 25 premium up front it could last two to three times as long so you're really getting more bang for your buck if you're going to use the battery for its full lifetime if you go with the lithium iron phosphate next let's talk about voltage the nominal voltage of lithium iron phosphate is actually lower than lithium ion with lithium iron phosphate you're talking about a nominal voltage of about 3.2 or 3.3 volts compared to lithium ion you've got a nominal voltage of 3.6 to 3.7 volts so with a lower voltage it actually plays nicer with 12-volt increments so for example if you're trying to build a volt lithium ion battery you're going to be falling somewhere between 3s and 4s because lithium ion at 3.6 volts per cell just doesn't play as nicely with 12 volt increments but lithium iron phosphate falls much closer to the sort of 12 volt 24 volt 36 volt increments so if you're doing a 12 volt application and you need to run something like a 12 volt inverter you're going to get much closer alignment to the typical lead acid 12 volt battery range going with lithium iron phosphate and lastly but definitely not the least most important is safety lithium iron phosphate cells are certainly safer than lithium ion because they just don't have the same combustion level it's really hard to make a lithium iron phosphate battery cell explode and it's actually pretty easy to make a lithium ion cell explode i mean you have to abuse it but i mean if you just short circuit one of those cells you can make it pop pretty easily as opposed to lithium iron phosphate because they just don't heat up so much when you abuse them it's really hard to make them combust they will heat up some they might vent a bit but they just don't have the same combustion level that a lithium ion cell has they don't just aren't that reactive either in terms of heat or chemically so they're a lot safer alternative to lithium ion if you're worried about fire safety all right so those are the main differences between lithium ion and lithium iron phosphate obviously both work really well and it really just depends on your application generally i've gone with lithium-ion because they're cheaper up front they're more plentiful in terms of the different types of cells you can get there's just more manufacturers but they do have some downsides like the safety like the lower cycle life so that's why for my next battery i want to try doing this with these larger format lithium iron phosphate cells if you want to check these out i will put a link in the description below so you can see these they're 2.99 per cell i think which is actually a pretty crazy deal if you do the math i've got 64 cells here so what i'm planning is a 4p 16s pack that's 4 cells in parallel and then 16 of those parallel sets in series and that's going to give me a 48 volts and 20 amp hour battery or probably closer to like 21 and a half because these are actually over capacity so that video is going to be coming up soon but in the meantime it is time to announce the winner of the giveaway for my last video and the randomly selected commenter is art so congratulations just let me know which one of my books you'd like you can choose from diy lithium batteries if you want to build a battery like what i'm going to be doing i also have diy solar power the ultimate do-it-yourself e-bike guide and electric motorcycles just let me know which one of my books you'd like and where to send it and anybody else who wants a chance to be the randomly selected commenter at the end of my next video just try putting a comment down below tell me anything you want and hopefully you'll be chosen next time and if you don't want to wait that long to hopefully win one of my books you can always find them on amazon alright thanks for watching everybody i'll be back soon with a video where i turn these into an e-bike battery see you next time everyone you

Channel: EbikeSchool.com

Views: 129,129

Rating: 4.8869643 out of 5

Keywords: 11-25-20

Id: fOMK8wu7DNA

Length: 8min 8sec (488 seconds)

Published: Fri Jan 08 2021